Filed Pursuant to Rule 424(b)(5)
Registration No. 333-197440

CALCULATION OF REGISTRATION FEE

Title of Each Class of Securities Offered	Amount to be Registered(1)	Proposed Maximum Aggregate Offering Price Per Share(1)	Proposed Maximum Aggregate Offering Price(1)	Amount of Registration Fee(2)
Common Stock, par value $0.01 per share	55,200,000	$10.8000	$596,160,000	$69,094.95

(1) Includes 7,200,000 shares of common stock which may be issued on exercise of a 30-day option granted to the underwriters to cover over-allotments, if any.

(2) This filing fee is calculated and being paid pursuant to Rule 457(r) of the Securities Act of 1933, as amended, and relates to the registration statement on Form S-3 (File No. 333-197440) filed by Oasis Petroleum Inc. on July 15, 2014.

Prospectus supplement to prospectus dated July 15, 2014

48,000,000 shares

Common stock

We are offering 48,000,000 shares of our common stock.

Our common stock is listed on the New York Stock Exchange under the symbol “OAS.” On October 17, 2016, the last reported trading price of our common stock as reported on the New York Stock Exchange was $11.23 per share.

Investing in our common stock involves risk. See “Risk Factors” beginning on page S-7 of this prospectus supplement.

	Price to Public		Underwriting Discounts and Commissions		Proceeds to Us (Before Expenses)
Per Share	$	10.8000	$	0.2154	$	10.5846
Total	$	518,400,000	$	10,339,200	$	508,060,800

The underwriters also have the option to purchase up to an additional 7,200,000 shares from us at the price set forth above within 30 days from the date of this prospectus supplement.

The shares are expected to be ready for delivery on or about October 21, 2016.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus supplement or the accompanying prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

Joint book-running managers

J.P. Morgan Goldman, Sachs & Co.

Co-Managers

Wells Fargo Securities Citigroup Morgan Stanley RBC Capital Markets

BB&T Capital Markets BBVA BOK Financial Securities, Inc. BTIG Capital One Securities

CIBC Capital Markets Citizens Capital Markets, Inc. Comerica Securities Credit Suisse Deutsche Bank Securities

Evercore ISI Heikkinen Energy Advisors IBERIA Capital Partners L.L.C. ING Johnson & Rice Company L.L.C.

Tudor, Pickering, Holt & Co. Regions Securities LLC

The date of this prospectus is October 18, 2016.

Table of contents

Prospectus supplement
About this prospectus supplement	S-ii
Where you can find more information	S-ii
Cautionary statement regarding forward-looking statements	S-iv
Summary	S-1
Risk factors	S-7
Use of proceeds	S-12
Capitalization	S-13
Price range of common stock	S-14
Dividend policy	S-14
Material U.S. federal income tax considerations for non-U.S. holders	S-15
Underwriting	S-19
Legal matters	S-25
Experts	S-25
Prospectus
About this prospectus	1
The company	1
Where you can find more information	2
Cautionary note regarding forward-looking statements	3
Risk factors	5
Ratio of earnings to fixed charges	5
Use of proceeds	5
Description of debt securities	6
Description of capital stock	18
Description of warrants	22
Plan of distribution	23
Legal matters	25
Experts	25

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About this prospectus supplement

This document is in two parts. The first part is the prospectus supplement and the documents incorporated by reference herein, which describes the specific terms of this offering of our common stock. The second part is the accompanying prospectus, which gives more general information, some of which may not apply to our common stock or this offering. If the information relating to the offering varies between the prospectus supplement and the accompanying prospectus, you should rely on the information in this prospectus supplement

You should rely only on the information contained in or incorporated by reference into this prospectus supplement, the accompanying prospectus and any related free writing prospectus. We have not, and the underwriters have not, authorized any dealer, salesman or other person to provide you with additional or different information. If anyone provides you with different or inconsistent information, you should not rely on it. This prospectus supplement and the accompanying prospectus are not an offer to sell or the solicitation of an offer to buy any securities other than the securities to which they relate and are not an offer to sell or the solicitation of an offer to buy securities in any jurisdiction to any person to whom it is unlawful to make an offer or solicitation in that jurisdiction. You should not assume that the information contained in this prospectus supplement is accurate as of any date other than the date on the front cover of this prospectus supplement, or that the information contained in any document incorporated by reference is accurate as of any date other than the date of the document incorporated by reference, regardless of the time of delivery of this prospectus supplement or any sale of a security.

Unless otherwise indicated or the context otherwise requires, all references in this prospectus supplement to “we,” “us,” “our,” “Oasis Petroleum” and the “Company” refer to Oasis Petroleum Inc. and its subsidiaries and the term “Oasis” refers to Oasis Petroleum Inc.

Where you can find more information

We file annual, quarterly and current reports and other information with the Securities and Exchange Commission (the “SEC”) (File No. 001- 34776) pursuant to the Securities Exchange Act of 1934, as amended (the “Exchange Act”). You may read and copy any documents that are filed at the SEC’s public reference room at 100 F Street, N.E., Washington, D.C. 20549. You may also obtain copies of these documents at prescribed rates from the public reference section of the SEC at its Washington address. Please call the SEC at 1-800-SEC-0330 for further information.

Our filings are also available to the public through the SEC’s website at www.sec.gov.

The SEC allows us to “incorporate by reference” information that we file with them, which means that we can disclose important information to you by referring you to documents previously filed with the SEC. The information incorporated by reference is an important part of this prospectus supplement, and the information that we later file with the SEC will automatically update and supersede this information. The following documents we filed with the SEC pursuant to the Exchange Act are incorporated herein by reference:

• our Annual Report on Form 10-K for the year ended December 31, 2015;

• the information specifically incorporated by reference into the Annual Report on Form 10-K from our definitive proxy statement on Schedule 14A, filed on March 24, 2016;

• our Quarterly Reports on Form 10-Q for the quarters ended March 31, 2016 and June 30, 2016;

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• our Current Reports on Form 8-K filed on January 28, 2016, February 2, 2016, May 10, 2016, July 29, 2016, September 19, 2016 and October 18, 2016 (excluding any information furnished pursuant to Item 2.02 or Item 7.01 of any such Current Report on Form 8-K); and

• the description of our common stock contained in our Registration Statement on Form 8-A12B filed on June 14, 2010, including any amendment to that form for the purpose of updating the description of our common stock.

These reports contain important information about us, our financial condition and our results of operations.

All future documents filed pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act (excluding any information furnished pursuant to Item 2.02 or Item 7.01 on any Current Report on Form 8-K) before the termination of the offering of securities under this prospectus supplement shall be deemed to be incorporated in this prospectus supplement by reference and to be a part hereof from the date of filing of such documents. Any statement contained herein, or in a document incorporated or deemed to be incorporated by reference herein, shall be deemed to be modified or superseded for purposes of this prospectus supplement to the extent that a statement contained herein or in any subsequently filed document that also is or is deemed to be incorporated by reference herein, modifies or supersedes such statement. Any such statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this prospectus supplement.

You may request a copy of these filings at no cost by writing or telephoning us at the following address and telephone number:

Oasis Petroleum Inc.

Attention: Investor Relations

1001 Fannin Street, Suite 1500

Houston, Texas 77002

Phone: (281) 404-9600

Fax: (281) 404-9702

We also maintain a website at http://www.oasispetroleum.com. However, the information on our website is not part of this prospectus supplement or the accompanying prospectus.

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Cautionary statement regarding forward-looking statements

This prospectus supplement, the accompanying prospectus and the documents we incorporate by reference herein contain forward-looking statements within the meaning of Section 27A of the Securities Act of 1933 (the “Securities Act”) and Section 21E of the Exchange Act. These forward-looking statements are subject to a number of risks and uncertainties, many of which are beyond our control. All statements, other than statements of historical fact included in this prospectus supplement, the accompanying prospectus and the documents we incorporate by reference herein, regarding our strategy, future operations, financial position, estimated revenues and losses, projected costs, prospects, plans and objectives of management are forward-looking statements. When used in this prospectus supplement, the accompanying prospectus and the documents we incorporate by reference herein, the words “could,” “believe,” “anticipate,” “intend,” “estimate,” “expect,” “may,” “continue,” “predict,” “potential,” “project” and similar expressions are intended to identify forward-looking statements, although not all forward-looking statements contain such identifying words. In particular, the factors discussed below and detailed under Item 1A. “Risk Factors” in our Annual Report on Form 10-K for the year ended December 31, 2015 could affect our actual results and cause our actual results to differ materially from expectations, estimates, or assumptions expressed in, forecasted in, or implied in such forward-looking statements.

Forward-looking statements may include statements about:

• our business strategy;

• estimated future net reserves and present value thereof;

• timing and amount of future production of oil and natural gas;

• drilling and completion of wells;

• estimated inventory of wells remaining to be drilled and completed;

• costs of exploiting and developing our properties and conducting other operations;

• availability of drilling, completion and production equipment and materials;

• availability of qualified personnel;

• owning and operating well services and midstream companies;

• infrastructure for salt water disposal;

• gathering, transportation and marketing of oil and natural gas, both in the Williston Basin and other regions in the United States;

• property acquisitions, including the Acquisition (as defined below);

• integration and benefits of property acquisitions or the effects of such acquisitions on our cash position and levels of indebtedness;

• the amount, nature and timing of capital expenditures;

• availability and terms of capital;

• our financial strategy, budget, projections, execution of business plan and operating results;

• cash flows and liquidity;

• oil and natural gas realized prices;

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• general economic conditions;

• operating environment, including inclement weather conditions;

• effectiveness of risk management activities;

• competition in the oil and natural gas industry;

• counterparty credit risk;

• environmental liabilities;

• governmental regulation and the taxation of the oil and natural gas industry;

• developments in oil-producing and natural gas-producing countries;

• technology;

• uncertainty regarding future operating results; and

• plans, objectives, expectations and intentions contained in this prospectus that are not historical.

All forward-looking statements speak only as of the date of this prospectus supplement, the accompanying prospectus and the documents we incorporate by reference herein. We disclaim any obligation to update or revise these statements unless required by securities law, and you should not place undue reliance on these forward-looking statements. Although we believe that our plans, intentions and expectations reflected in or suggested by the forward-looking statements we make in this prospectus supplement, the accompanying prospectus and the documents we incorporate by reference herein are reasonable, we can give no assurance that these plans, intentions or expectations will be achieved. Some of the key factors which could cause actual results to vary from our expectations include changes in oil and natural gas prices, the timing of planned capital expenditures, availability of acquisitions, uncertainties in estimating proved reserves and forecasting production results, operational factors affecting the commencement or maintenance of producing wells, the condition of the capital markets generally, as well as our ability to access them, the proximity to and capacity of transportation facilities, and uncertainties regarding environmental regulations or litigation and other legal or regulatory developments affecting our business, as well as those factors discussed below and elsewhere in this prospectus supplement, the accompanying prospectus and the documents we incorporate by reference herein, all of which are difficult to predict. In light of these risks, uncertainties and assumptions, the forward-looking events discussed may not occur. These cautionary statements qualify all forward-looking statements attributable to us or persons acting on our behalf.

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Summary

This summary provides a brief overview of information contained elsewhere in this prospectus supplement, the accompanying prospectus and the documents we incorporate by reference. Because it is abbreviated, this summary does not contain all of the information that you should consider before investing in our common stock in this offering. You should read the entire prospectus supplement, the accompanying prospectus, the documents incorporated by reference and the other documents to which we refer for a more complete understanding of our business and this offering. Please read the section entitled “Risk Factors” beginning on page S-7 of this prospectus supplement and beginning on page 5 of the accompanying prospectus, and additional information contained in our Annual Report on Form 10-K for the year ended December 31, 2015, which is incorporated by reference in this prospectus supplement for more information about important factors you should consider before investing in our common stock in this offering.

Overview

We are an independent exploration and production company focused on the acquisition and development of unconventional oil and natural gas resources in the North Dakota and Montana regions of the Williston Basin. As of December 31, 2015, we have accumulated 484,745 net leasehold acres in the Williston Basin, of which approximately 91% is held by production. We are currently exploiting significant resource potential from the Bakken and Three Forks formations, which are present across a substantial portion of our acreage. We believe the location, size and concentration of our acreage create an opportunity for us to achieve cost, recovery and production efficiencies through the development of our project inventory. Our management team has a proven track record in identifying, acquiring and executing large, repeatable development drilling programs, which we refer to as “resource conversion” opportunities, and has substantial Williston Basin experience. We have built our Williston Basin assets primarily through acquisitions and development activities.

In addition to our exploration and production segment, we have a well services business segment and a midstream services business segment. Our well services business segment performs services for the oil and natural gas wells operated by our exploration and production segment. Revenues for the well services segment are derived from providing well services, product sales and equipment rentals. Our midstream services business segment owns and operates salt water gathering pipelines, salt water disposal wells, fresh water distribution pipelines, oil and natural gas gathering pipelines and a natural gas processing plant, and performs salt water gathering and disposal and other midstream services for our oil and natural gas wells operated by our exploration and production segment. Revenues for the midstream segment are primarily derived from salt water pipeline transport, salt water disposal, fresh water sales and natural gas gathering.

Recent developments

Acquisition

On October 17, 2016, we entered into a Purchase and Sale Agreement (the “Purchase Agreement”) with SM Energy Company (“SM Energy”). Pursuant to the Purchase Agreement, we will acquire from SM Energy approximately 55,000 net acres in the Williston Basin (the “Acquisition”) for a purchase price of approximately $785 million in cash (the “Purchase Price”). We will pay to SM Energy a deposit of approximately $78.5 million contemporaneously with the execution of the Purchase Agreement. The effective date for the acquisition is October 1, 2016 and the transaction is expected to close on December 1, 2016. The transaction is subject to customary closing conditions. The Purchase Agreement contains customary representations and warranties,

S-1

covenants, indemnification, and termination provisions. The Purchase Agreement contains various purchase price adjustments to be calculated as of the closing date. We expect to partially fund the Purchase Price with the net proceeds from this offering and the remainder with borrowings under our revolving credit facility or through additional capital markets transactions, including the sale of debt or equity securities.

The assets underlying the Acquisition consist of working interests in approximately 55,000 net acres, and the Company estimates that the acres contain approximately 226 gross operated drilling locations. The following table provides detail on key operational highlights for Oasis and the acquisition:

	Oasis Stand-Alone		Acquisition		Pro Forma Combined
Net acreage(1)		485,000		55,000		540,000
Gross Core Op Inventory Estimate(2)		554		130		684
Net Core Op Inventory Estimate(2)		333		68		401
Total Net Core Inventory Estimate(2)		333		92		425

(1) Our net acreage is as of December 31, 2015.

(2) Our Stand-Alone inventory is based on year-end 2015 drilling locations, adjusted for wells expected to be completed in 2016. Acquisition inventory is based on similar methodology that we used at year-end 2015 on our own inventory.

We cannot assure you that we will complete the Acquisition on the terms contemplated in this prospectus supplement or at all. The consummation of this offering is not conditioned on the closing of the Acquisition, and the consummation of this offering is not a condition to the completion of the Acquisition. Please read “Risk Factors—Risks Related to the Acquisition” in this prospectus supplement for more information on the Acquisition and the risks related thereto.

3rd Quarter 2016 Update

Management has prepared, and is responsible for, the preliminary financial data presented below, which is based on the most current information available. The Company’s normal financial reporting processes with respect to the preliminary financial data have not been fully completed, and PricewaterhouseCoopers LLP has not audited, reviewed, compiled or performed any procedures with respect to the accompanying preliminary financial data. Accordingly, PricewaterhouseCoopers LLP does not express an opinion or any other form of assurance with respect thereto. As a result, the Company’s actual financial results could be different from this preliminary financial data, and any differences could be material. The summary preliminary financial data below has been prepared on a basis consistent with our unaudited condensed consolidated financial statements for the three months ended June 30, 2016. This summary is not intended to be a comprehensive statement of our unaudited financial results for this period. The results of operations for an interim period, including the summary preliminary financial data provided below, may not give a true indication of the results to be expected for a full year or any future period.

Our average daily production rate for the third quarter of 2016 was 48,509 barrels of oil equivalent per day (“Boepd”) (approximately 81% oil). We completed and placed on production 17 gross (7.1 net) wells during the third quarter of 2016. As of September 30, 2016, we had 80 gross wells awaiting completion. Capital expenditures ranged between $76 million and $81 million for the third quarter of 2016.

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The following table provides our preliminary estimates for oil prices and differentials and natural gas prices for the third quarter of 2016:

	3Q16
WTI (NYMEX)		$44.94
Realized Price for Oil		$40.50 – $40.60
Natural Gas ($ per mcf)		$1.80 – $1.90

During the third quarter of 2016, we had net cash settlement receipts from derivative instruments of $11.8 million in the third quarter of 2016, including receipts from contract settlements in June 2016, July 2016 and August 2016. Our derivative instruments do not qualify for and were not designated as hedging instruments for accounting purposes.

The following table provides our preliminary expense estimates for the third quarter of 2016:

Metric	3Q16
Lease Operating Expenses ($/boe)		$7.95 – $8.05
Marketing, Transportation and Gathering Expenses(1)		$1.55 – $1.65
General and Administrative Expenses ($ in millions)		$22.7 – $22.9
Production Taxes (% of oil and gas revenues)		9.2% – 9.3%

(1) Excludes non-cash valuation charges on pipeline imbalances and bulk oil purchase.

Liquidity and Long Term Debt

As of September 30, 2016, we had total cash and cash equivalents of $13.8 million. In addition, we had $195.0 million of borrowings and $12.3 million of outstanding letters of credit issued under our revolving credit facility, resulting in an unused borrowing base capacity of $942.7 million as of September 30, 2016.

On October 14, 2016, we entered into an amendment to our Second Amended and Restated Credit Agreement with our bank syndicate in connection with the scheduled redetermination of our borrowing base. Following the redetermination, the borrowing base and elected commitments were reaffirmed at $1,150 million. The next redetermination of our borrowing base is scheduled for April 1, 2017.

On September 28, 2016, we completed our tender offers to repurchase certain outstanding senior unsecured notes and on September 29, 2016, the underwriters of our offering of 2.625% senior unsecured convertible notes due 2023 (“Convertible Notes”) exercised the full over-allotment option to purchase an additional $25 million of Convertible Notes. Our long-term debt consists of the following:

($ in millions)	September 30, 2016		December 31, 2015
Senior secured revolver line of credit(1)	$	195.0	$	138.0
Senior unsecured notes(2)
7.25% senior unsecured notes due 2019	$	54.3	$	400.0
6.5% senior unsecured notes due 2021	$	395.5	$	400.0
6.875% senior unsecured notes due 2022	$	937.1	$	1,000.0
6.875% senior unsecured notes due 2023	$	366.1	$	400.0
2.625% senior unsecured convertible notes due 2023	$	300.0		—
Total long-term debt	$	2,248.0	$	2,338.0

(1) As of October 17, 2016, we had $312.0 million of borrowings outstanding under our revolving credit facility and had $12.3 million of outstanding letters of credit issued under our revolving credit facility.

(2) Excludes deferred financing costs for the senior unsecured notes and the debt discount for the equity component of the Convertible Notes.

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Hedging Activity

As of October 17, 2016, we had the following outstanding commodity derivative contracts, all of which are priced off of WTI and settle monthly:

Volume in Mbopd	3Q16		4Q16		1H17		2H17		1H18		2H18
Swap
Volume		32.0		33.0		15.0		13.0		3.0		2.0
Price	$	49.13	$	49.20	$	48.19	$	48.68	$	53.97	$	53.99
Collars
Volume		—		—		5.0		5.0		—		—
Floor					$	44.00	$	44.00
Ceiling					$	53.14	$	53.14
3-way
Volume		—		—		6.0		6.0		—		—
Sub Floor					$	31.67	$	31.67
Floor					$	45.83	$	45.83
Ceiling					$	59.94	$	59.94
Total Volume		32.0		33.0		26.0		24.0		3.0		2.0

Additionally, we have swaps priced off of NYMEX Natural Gas of 6,000 mmbtu/d at a weighted average price of $3.21 in 2017.

Corporate information

Our principal executive offices are located at 1001 Fannin Street, Suite 1500, Houston, Texas 77002, and our telephone number at that address is (281) 404-9500. Our website is located at http://www.oasispetroleum.com. However, the information on our website is not part of this prospectus supplement, and you should rely only on the information contained in this prospectus supplement, the accompanying prospectus, any related free writing prospectus and in the documents incorporated herein by reference when making a decision as to whether to buy our common stock in this offering.

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The offering

Issuer Oasis Petroleum Inc.

Shares of common stock offered 48,000,000 shares.

Option to purchase additional shares The underwriters also have the option to purchase up to an additional 7,200,000 shares from us within 30 days from the date of this prospectus supplement.

Shares of common stock outstanding following this offering(1) 229,192,428 shares (236,392,428 shares if the underwriters exercise their option to purchase additional shares in full).

Use of proceeds We estimate that, after deducting underwriting discounts and commissions and estimated offering expenses payable by us, we will receive approximately $507.8 million of net proceeds from this offering, or $584.0 million if the underwriters exercise in full their option to purchase additional shares. We expect to partially fund the cash portion of the Purchase Price with the net proceeds from this offering and the remainder with borrowings under our revolving credit facility or through additional capital markets transactions, including the sale of debt or equity securities. However, the consummation of this offering is not conditioned upon the completion of the Acquisition, and the consummation of this offering is not a condition to the completion of the Acquisition. There can be no assurance that we will complete the Acquisition on the terms described herein or at all. If the Acquisition is not consummated, we intend to use the net proceeds of this offering for general corporate purposes, which may include funding a portion of our 2017 capital budget. Please read “Use of Proceeds.”

(1) Based on 181,192,428 shares outstanding as of October 17, 2016.

Unless we indicate otherwise or the context otherwise requires, all of the information in this prospectus supplement:

• assumes no exercise of the underwriters’ option to purchase additional shares of common stock;

• includes outstanding shares of unvested restricted common stock; and

• does not include i) approximately 7,514,817 million shares of common stock authorized, but unissued and available for issuance, under our Amended and Restated 2010 Long-Term Incentive Plan, or ii) the shares issuable if earned under 1,387,619 performance share units (“PSUs”) outstanding as of October 17, 2016, which can range from 0% to 200% of the initial PSUs awarded based on a comparison of the total shareholder return (“TSR”) achieved with respect to shares of the Company’s common stock against the TSR achieved by a defined peer group at the end of the designated performance periods.

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Risk factors

Investing in our common stock involves substantial risk. You should carefully consider the risk factors set forth or cross-referenced in the sections entitled “Risk Factors” beginning on page S-7 of this prospectus supplement and beginning on page 5 of the accompanying prospectus, and the other information contained in this prospectus supplement and the accompanying prospectus and the documents incorporated by reference therein, prior to making an investment in our common stock.

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Risk factors

An investment in our common stock involves risk. In addition to the risks described below, you should also carefully read the risk factors included in the section entitled “Risk Factors” in our Annual Report on Form 10-K for the year ended December 31, 2015, together with all of the other information included in this prospectus supplement, the accompanying prospectus and the documents we have incorporated by reference into this prospectus supplement in evaluating an investment in our common stock. If any of the described risks actually were to occur, our business, financial condition or results of operations could be affected materially and adversely. In that case, the trading price of our common stock could decline and you could lose all or part of your investment.

Risks related to the acquisition

We may not consummate the acquisition, and this offering is not conditioned on the consummation of the acquisition.

We intend to use the net proceeds of this offering to fund a portion of the Purchase Price described above under “Prospectus Supplement Summary—Recent Developments—Acquisition.” However, this offering is not conditioned on the consummation of the Acquisition, which is subject to various customary and other closing conditions. There can be no assurances that these conditions will be satisfied, the financing for the Purchase Price will be successfully obtained, or that the Acquisition will be consummated.

This offering is not conditioned on the consummation of the Acquisition. Therefore, upon the closing of this offering, you will become a holder of our common stock regardless of whether the Acquisition is consummated, delayed or terminated. If the Acquisition is delayed or terminated or consummated on terms different than those described herein, the price of our common stock may decline. In addition, if the Acquisition is not consummated, our management will have broad discretion in the application of the net proceeds of this offering and could apply the proceeds in ways that you or other stockholders may not approve, which could adversely affect the market price of our common stock.

If the acquisition is consummated, we may be unable to successfully integrate the assets’ operations or to realize anticipated cost savings, revenues or other benefits of the acquisition.

Our ability to achieve the anticipated benefits of the Acquisition will depend in part upon whether we can integrate the acquired assets and operations into our existing businesses in an efficient and effective manner. We may not be able to accomplish this integration process successfully. The successful acquisition of producing properties, including those acquired from SM Energy, requires an assessment of several factors, including:

• recoverable reserves;

• future natural gas and oil prices and their appropriate differentials;

• availability and cost of transportation of production to markets;

• availability and cost of drilling equipment and of skilled personnel;

• development and operating costs including access to water and potential environmental and other liabilities;

• regulatory, permitting and similar matters; and

• our ability to obtain external financing to fund the Purchase Price.

The accuracy of these assessments is inherently uncertain. In connection with these assessments, we have performed a review of the subject properties that we believe to be generally consistent with industry practices.

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Our review may not reveal all existing or potential problems or permit us to become sufficiently familiar with the properties to fully assess their deficiencies and potential recoverable reserves. Inspections were not performed on every well, and environmental problems are not necessarily observable even when an inspection is undertaken. The integration process may be subject to delays or changed circumstances, and we can give no assurance that the acquired properties will perform in accordance with our expectations or that our expectations with respect to integration or cost savings as a result of the Acquisition will materialize. The Acquisition involves risks that may cause our business to suffer, including:

• diversion of our management’s attention;

• the challenge and cost of integrating acquired operations, information management and other technology systems and business cultures with those of ours while carrying on our ongoing business; and

• the failure to realize the full benefit that we expect in estimated proved reserves, production volume, cost savings from operating synergies or other benefits anticipated from the Acquisition, or to realize these benefits within the expected time frame.

We will incur significant transaction and acquisition-related costs in connection with the acquisition.

We expect to incur significant costs associated with the Acquisition and combining the operations of the assets with our operations. The substantial majority of the expenses resulting from the Acquisition will be composed of transaction costs related to the Acquisition and our integration efforts. Unanticipated costs may be incurred in the integration process. Although we expect that the elimination of duplicative costs, as well as the realization of other efficiencies related to the integration of the Acquisition with our assets, should allow us to offset incremental transaction and acquisition-related costs over time, this net benefit may not be achieved in the near term, or at all.

In addition to the proceeds from this offering, we may seek to fund a portion of the purchase price for the acquisition through additional debt financing.

In addition to the proceeds from this offering, we may seek to fund a portion of the purchase price for the Acquisition through additional debt financing, including through borrowings under our revolving credit facility. If we incur additional debt, the risks associated with our leverage may be exacerbated.

Risks related to this offering and our common stock

Further declines, or extended current low commodity prices in oil and, to a lesser extent, natural gas prices may adversely affect our business, financial condition or results of operations and our ability to meet our capital expenditure obligations and financial commitments.

The price we receive for our oil and, to a lesser extent, natural gas, heavily influences our revenue, profitability, access to capital and future rate of growth. Oil and natural gas are commodities and, therefore, their prices are subject to wide fluctuations in response to relatively minor changes in supply and demand. For example, average daily prices for WTI crude oil ranged from a high of $51.23 per barrel to a low of $26.19 per barrel during 2016. Average daily prices for NYMEX Henry Hub natural gas ranged from a high of $3.19 per MMBtu to a low of $1.49 per MMBtu during 2016. Historically, the markets for oil and natural gas have been volatile. These markets will likely continue to be volatile in the future. The prices we receive for our production, and the levels of our production, depend on numerous factors beyond our control. These factors include the following:

• worldwide and regional economic conditions impacting the global supply and demand for oil and natural gas;

• the actions of OPEC;

• the price and quantity of imports of foreign oil and natural gas;

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• political conditions in or affecting other oil-producing and natural gas-producing countries, including the current conflicts in the Middle East and conditions in South America, China, India and Russia;

• the level of global oil and natural gas exploration and production;

• the level of global oil and natural gas inventories;

• localized supply and demand fundamentals and regional, domestic and international transportation availability;

• weather conditions and natural disasters;

• domestic and foreign governmental regulations;

• speculation as to the future price of oil and the speculative trading of oil and natural gas futures contracts;

• price and availability of competitors’ supplies of oil and natural gas;

• technological advances affecting energy consumption; and

• the price and availability of alternative fuels.

Substantially all of our production is sold to purchasers under short-term (less than twelve-month) contracts at market-based prices. Low oil and natural gas prices will reduce our cash flows, borrowing ability, the present value of our reserves and our ability to develop future reserves. Low oil and natural gas prices may also reduce the amount of oil and natural gas that we can produce economically and may affect our proved reserves.

The market price of our common stock has fluctuated substantially in the past and is likely to fluctuate in the future as a result of a number of factors.

The market price of our common stock has historically experienced and may continue to experience volatility. For example, since January 1, 2015, the market price of our common stock has ranged between $3.40 and $19.63. Such fluctuations may continue because of numerous factors, including:

• domestic and worldwide supply of and demand for oil, natural gas and NGL and corresponding fluctuations in the price of oil, natural gas and NGLs;

• quarterly fluctuations in our operating results and those of our competitors;

• changes in stock market analysts’ estimates of our future performance and the future performance of our competitors;

• sales of a high volume of shares of our common stock by our stockholders;

• events affecting other companies that the market deems comparable to us;

• general conditions in the industries in which we operate; and

• general economic conditions in the United States and other areas.

Our financial position, our cash flows, our results of operations and our stock price could be materially adversely affected if commodity prices do not improve or decline further. In addition, in recent years the stock market has experienced extreme price and volume fluctuations. This volatility has had a significant effect on the market prices of securities issued by many companies for reasons unrelated to their operating performance. Our stock price may experience extreme volatility due to uncertainty regarding commodity prices. These market fluctuations, regardless of the cause, may materially and adversely affect our stock price, regardless of our operating results.

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Our amended and restated certificate of incorporation and amended and restated bylaws, as well as Delaware law, contain provisions that could discourage acquisition bids or merger proposals, which may adversely affect the market price of our common stock.

Our amended and restated certificate of incorporation authorizes our Board of Directors to issue preferred stock without stockholder approval. If our Board of Directors elects to issue preferred stock, it could be more difficult for a third party to acquire us. In addition, some provisions of our amended and restated certificate of incorporation and amended and restated bylaws could make it more difficult for a third party to acquire control of us, even if the change of control would be beneficial to our stockholders, including:

• a classified Board of Directors, so that only approximately one-third of our directors are elected each year;

• limitations on the removal of directors; and

• limitations on the ability of our stockholders to call special meetings and establish advance notice provisions for stockholder proposals and nominations for elections to the Board of Directors to be acted upon at meetings of stockholders.

In addition, we are subject to Section 203 of the Delaware General Corporation Law, which regulates corporate takeovers. As a result, we are prohibited from engaging in any business combination with any “interested stockholder,” meaning generally that a stockholder who beneficially owns more than 15% of our stock cannot acquire us for a period of three years from the date this person became an interested stockholder, unless various conditions are met, such as approval of the transaction by our Board of Directors.

Investors in this offering may experience future dilution.

In order to raise additional capital, effect acquisitions, or for other purposes, we may in the future offer additional shares of our common stock or other securities convertible into, or exchangeable for, our common stock at prices that may not be the same as the price per share of this offering. We have an effective shelf registration statement from which additional shares of common stock and other securities can be offered. We cannot assure you that we will be able to sell shares or other securities in any other offering at a price per share that is equal to or greater than the price per share paid by investors in this offering. If the price per share at which we sell additional shares of our common stock or related securities in future transactions is less than the price per share in this offering, investors who purchase our common stock in this offering will suffer a dilution of their investment. In addition, equity awards under our equity compensation plan may cause further dilution.

Sales of a substantial amount of our common stock in the public market, or the perception that these sales may occur, could reduce the market price of our common stock. This could also impair our ability to raise additional capital through the sale of our securities.

We do not intend to pay, and we are currently prohibited from paying, dividends on our common stock and, consequently, our shareholders’ only opportunity to achieve a return on their investment is if the price of our stock appreciates.

We do not plan to declare dividends on shares of our common stock in the foreseeable future. Additionally, we are currently prohibited from making any cash dividends pursuant to the terms of our revolving credit facility and the indentures governing our senior unsecured notes. Consequently, our shareholders’ only opportunity to achieve a return on their investment in us will be if the market price of our common stock appreciates, which may not occur, and the shareholder sells their shares at a profit. There is no guarantee that the price of our common stock will ever exceed the price that the shareholder paid.

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We expect our future capital expenditures, together with other expenses (including debt expense) will require us to incur future borrowings under our revolving credit facility or obtain financing from other sources.

Our exploration and development activities are capital intensive. Our capital expenditure budget for 2016 is approximately $400 million, which includes $340 million for exploration and development capital expenditures and $60 million for non-exploration and development capital expenditures. We expect that our future capital expenditures will require us to incur future borrowings under our revolving credit facility or obtain financing from other sources, and that our operating cash flows alone will be insufficient to cover all of our expenses for 2016 and future periods.

For additional information regarding our capital expenditures, debt expense, financing and related impacts of commodity prices, please also read the Risk Factors in our Form 10-K for the year ended December 31, 2015 under “Our exploration, development and exploitation projects require substantial capital expenditures. We may be unable to obtain needed capital or financing on satisfactory terms, which could lead to expiration of our leases or a decline in our estimated net oil and natural gas reserves,” “We may not be able to generate enough cash flow to meet our debt obligations” and “Further declines, or extended current low commodity prices, in oil and, to a lesser extent, natural gas prices may adversely affect our business, financial condition or results of operations and our ability to meet our capital expenditure obligations and financial commitments.”

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Use of proceeds

We estimate that, after deducting underwriting discounts and commissions and estimated offering expenses payable by us, we will receive approximately $507.8 million of net proceeds from this offering, or $584.0 million if the underwriters exercise their option to purchase additional shares in full.

We expect to partially fund the cash portion of the Purchase Price with the net proceeds from this offering and the remainder with borrowings under our revolving credit facility or through additional capital markets transactions, including the sale of debt or equity securities. However, consummation of this offering is not conditioned upon the completion of the Acquisition, and the consummation of this offering is not a condition to the completion of the Acquisition.

There can be no assurance that we will complete the Acquisition on the terms described herein or at all. If the Acquisition is not consummated, we intend to use the net proceeds of this offering for general corporate purposes, which may include funding a portion of our 2017 capital budget. Please read “Summary—Recent Developments” for more information regarding the Acquisition.

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Capitalization

The following table sets forth our unaudited capitalization at June 30, 2016:

• on an actual basis;

• on an as adjusted basis to give effect to the issuance and sale of $300 million in aggregate principal amount of our convertible senior notes and the completion of our tender offers to repurchase certain senior notes; and

• on an as further adjusted basis to give effect to the issuance and sale of our common stock offered hereby and the application of the estimated net proceeds therefrom as set forth under “Use of Proceeds.”

	As of June 30, 2016
	Actual			As adjusted			As further adjusted
	(In thousands)
Cash and Cash Equivalents(1)	$	6,475		$	—		$	—
Long-term Debt(2)(3):
Revolving credit facility(4)		35,000			107,560			107,560
7.25% Senior Notes due 2019		399,000			54,275			54,275
6.5% Senior Notes due 2021		397,697			395,501			395,501
6.875% Senior Notes due 2022		940,500			937,080			937,080
6.875% Senior Notes due 2023		386,200			366,094			366,094
2.625% Convertible Senior Notes due 2023(5)		—			300,000			300,000
Total long-term debt		2,158,397			2,160,510			2,160,510
Stockholders’ Equity:
Common stock, $0.01 par value; 450,000,000 shares authorized; 181,200,581 shares issued and 180,399,060 outstanding actual and as adjusted; 229,200,581 shares issued and 228,399,060 outstanding, as further adjusted		1,777			1,777			2,257
Treasury stock, at cost, 801,521 shares		(15,140	)		(15,140	)		(15,140	)
Additional paid-in-capital(5)		1,693,583			1,693,583			2,200,914
Retained earnings		680,135			680,135			680,135
Total stockholders’ equity		2,360,355			2,360,355			2,868,166
Total Capitalization	$	4,518,752		$	4,520,865		$	5,028,676

(1) As further adjusted amount reflects the payment of approximately $507.8 million to fund a portion of the purchase price for the Acquisition. Without adjusting for such payment, as further adjusted cash and cash equivalents would be $507.8 million as of June 30, 2016.

(2) Amounts exclude unamortized deferred financing costs.

(3) As of October 17, 2016 we had $54.3 million, $395.5 million, $937.1 million and $366.1 million outstanding of our 7.25% Senior Notes due 2019, 6.5% Senior Notes due 2021, 6.875% Senior Notes due 2022 and 6.875% Senior Notes due 2023, respectively. On September 14, 2016 we issued $275 million principal amount of our 2.625% Convertible Senior Notes due 2023 ($300 million after the over allotment option was exercised on September 28, 2016) all of which is still outstanding.

(4) As of October 17, 2016, we had $312.0 million of borrowings outstanding under our revolving credit facility, including the deposit amount for the Acquisition, and had $12.3 million of outstanding letters of credit issued under our revolving credit facility.

(5) In accordance with ASC 470-20, convertible debt that may be wholly or partially settled in cash is required to be separated into a liability and an equity component, such that interest expense reflects the issuer’s nonconvertible debt interest rate. Upon issuance, a debt discount is recognized as a decrease in debt and an increase in equity. The debt component accretes up to the principal amount over the expected term of the debt. ASC 470-20 (additional paid-in capital) does not affect the actual amount that we are required to repay. The amounts presented herein are not separated into a liability and an equity component and are not adjusted for any debt discount.

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Price range of common stock

Our common stock is listed on the New York Stock Exchange under the symbol “OAS.” The following table shows, for the periods indicated, the high and low reported sale prices for our common stock, as reported on the New York Stock Exchange.

	Sales price
	High		Low
2014:
First quarter	$	47.28	$	38.68
Second quarter	$	56.38	$	41.01
Third quarter	$	58.09	$	40.85
Fourth quarter	$	41.90	$	10.64
2015:
First quarter	$	19.63	$	12.05
Second quarter	$	18.86	$	14.23
Third quarter	$	15.85	$	8.04
Fourth quarter	$	14.15	$	6.34
2016:
First quarter	$	8.78	$	3.40
Second quarter	$	11.54	$	6.70
Third quarter	$	11.83	$	6.56
Fourth quarter (through October 17, 2016)	$	12.14	$	10.83

On October 17, 2016, the last sales price of our common stock as reported on the New York Stock Exchange was $11.23 per share.

The number of shareholders of record of our common stock was approximately 504 as of October 17, 2016.

Dividend policy

We have not paid, and do not intend to pay in the foreseeable future, cash dividends on our common stock. Covenants contained in our revolving credit facility and the indentures governing our senior notes and convertible senior notes restrict the payment of dividends on our common stock. We currently intend to retain all future earnings to fund the development and growth of our business. Any payment of future dividends will be at the discretion of our Board of Directors and will depend on, among other things, our earnings, financial condition, capital requirements, level of indebtedness, statutory and contractual restrictions applying to the payment of dividends and other considerations that our Board of Directors deems relevant.

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Material U.S. federal income tax considerations for non-U.S. holders

The following is a summary of the material U.S. federal income tax considerations related to the purchase, ownership and disposition of our common stock by a non-U.S. holder (as defined below), that holds our common stock as a “capital asset” (generally property held for investment). This summary is based on the provisions of the Internal Revenue Code of 1986, as amended (the “Code”), U.S. Treasury regulations, administrative rulings and judicial decisions, all as in effect on the date hereof, and all of which are subject to change, possibly with retroactive effect. We have not sought any ruling from the Internal Revenue Service (“IRS”) with respect to the statements made and the conclusions reached in the following summary, and there can be no assurance that the IRS or a court will agree with such statements and conclusions.

This summary does not address all aspects of U.S. federal income taxation that may be relevant to non-U.S. holders in light of their personal circumstances. In addition, this summary does not address U.S. federal estate or gift tax laws, any state, local or non-U.S. tax laws or any tax treaties. This summary also does not address tax considerations applicable to investors that may be subject to special treatment under the U.S. federal income tax laws, such as:

• banks, insurance companies or other financial institutions;

• tax-exempt or governmental organizations;

• qualified foreign pension funds;

• dealers in securities or foreign currencies;

• traders in securities that use the mark-to-market method of accounting for U.S. federal income tax purposes;

• persons subject to the alternative minimum tax;

• partnerships or other pass-through entities for U.S. federal income tax purposes or holders of interests therein;

• persons deemed to sell our common stock under the constructive sale provisions of the Code;

• persons that acquired our common stock through the exercise of employee stock options or otherwise as compensation or through a tax-qualified retirement plan;

• certain former citizens or long-term residents of the United States; and

• persons that hold our common stock as part of a straddle, appreciated financial position, synthetic security, hedge, conversion transaction or other integrated investment or risk reduction transaction.

PROSPECTIVE INVESTORS ARE ENCOURAGED TO CONSULT THEIR TAX ADVISORS WITH RESPECT TO THE APPLICATION OF THE U.S. FEDERAL INCOME TAX LAWS TO THEIR PARTICULAR SITUATION, AS WELL AS ANY TAX CONSEQUENCES OF THE PURCHASE, OWNERSHIP AND DISPOSITION OF OUR COMMON STOCK ARISING UNDER THE U.S. FEDERAL ESTATE AND GIFT TAX LAWS OR UNDER THE LAWS OF ANY STATE, LOCAL, NON-U.S. OR OTHER TAXING JURISDICTION OR UNDER ANY APPLICABLE INCOME TAX TREATY.

Non-U.S. holder defined

For purposes of this discussion, a “non-U.S. holder” is a beneficial owner of our common stock that is not for U.S. federal income tax purposes a partnership or any of the following:

• an individual who is a citizen or resident of the United States;

• a corporation (or other entity taxable as a corporation for U.S. federal income tax purposes) created or organized in or under the laws of the United States, any state thereof or the District of Columbia;

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• an estate the income of which is subject to U.S. federal income tax regardless of its source; or

• a trust (i) whose administration is subject to the primary supervision of a U.S. court and which has one or more United States persons who have the authority to control all substantial decisions of the trust or (ii) which has made a valid election under applicable U.S. Treasury regulations to be treated as a United States person.

If a partnership (including an entity or arrangement treated as a partnership for U.S. federal income tax purposes) holds our common stock, the tax treatment of a partner in the partnership generally will depend upon the status of the partner, upon the activities of the partnership and upon certain determinations made at the partner level. Accordingly, we urge partners in partnerships (including entities or arrangements treated as partnerships for U.S. federal income tax purposes) considering the purchase of our common stock to consult their tax advisors regarding the U.S. federal income tax considerations of the purchase, ownership and disposition of our common stock by such partnership.

Distributions

We do not expect to pay any distributions on our common stock in the foreseeable future. However, in the event we do make distributions of cash or other property on our common stock, such distributions will constitute dividends for U.S. federal income tax purposes to the extent paid from our current or accumulated earnings and profits, as determined under U.S. federal income tax principles. To the extent those distributions exceed our current and accumulated earnings and profits, the distributions will be treated as a non-taxable return of capital to the extent of the non-U.S. holder’s tax basis in our common stock and thereafter as capital gain from the sale or exchange of such common stock. See “—Gain on Disposition of Common Stock.” Dividends paid to a non-U.S. holder on our common stock generally will be subject to U.S. withholding tax at a rate of 30% unless an applicable income tax treaty provides for a lower rate. To receive the benefit of a reduced treaty rate, a non-U.S. holder must provide the applicable withholding agent with an IRS Form W-8BEN or IRS Form W-8BEN-E (or other applicable or successor form) certifying qualification for the reduced rate.

Dividends paid to a non-U.S. holder that are effectively connected with a trade or business conducted by the non-U.S. holder in the United States (and, if required by an applicable income tax treaty, that are treated as attributable to a permanent establishment maintained by the non-U.S. holder in the United States) generally will be taxed on a net income basis at the rates and in the manner generally applicable to United States persons (as defined under the Code). Such effectively connected dividends will not be subject to U.S. withholding tax if the non-U.S. holder satisfies certain certification requirements by providing the applicable withholding agent a properly executed IRS Form W-8ECI certifying eligibility for exemption. If the non-U.S. holder is a corporation, it may also be subject to a branch profits tax (at a 30% rate or such lower rate as specified by an applicable income tax treaty) on its effectively connected earnings and profits (as adjusted for certain items).

Gain on disposition of common stock

Subject to the discussion below under “—Additional Withholding Requirements under FATCA,” a non-U.S. holder generally will not be subject to U.S. federal income tax on any gain realized upon the sale or other disposition of our common stock unless:

• the non-U.S. holder is an individual who is present in the United States for a period or periods aggregating 183 days or more during the calendar year in which the sale or disposition occurs and certain other conditions are met;

• the gain is effectively connected with a trade or business conducted by the non-U.S. holder in the United States (and, if required by an applicable income tax treaty, is attributable to a permanent establishment maintained by the non-U.S. holder in the United States); or

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• our common stock constitutes a U.S. real property interest by reason of our status as a United States real property holding corporation (“USRPHC”) for U.S. federal income tax purposes.

A non-U.S. holder described in the first bullet point above will be subject to U.S. federal income tax at a rate of 30% (or such lower rate as specified by an applicable income tax treaty) on the amount of such gain, which generally may be offset by U.S. source capital losses.

A non-U.S. holder whose gain is described in the second bullet point above or, subject to the exceptions described in the next paragraph, the third bullet point above, generally will be taxed on a net income basis at the rates and in the manner generally applicable to United States persons (as defined under the Code) unless an applicable income tax treaty provides otherwise. If the non-U.S. holder is a corporation, it may also be subject to a branch profits tax (at a 30% rate or such lower rate as specified by an applicable income tax treaty) on its effectively connected earnings and profits (as adjusted for certain items) which will include such gain.

Generally, a corporation is a USRPHC if the fair market value of its U.S. real property interests equals or exceeds 50% of the sum of the fair market value of its worldwide real property interests and its other assets used or held for use in a trade or business. Because of the oil and natural gas properties and other real property assets we own, we believe that we currently are, and expect to remain for the foreseeable future, a USRPHC for U.S. federal income tax purposes. However, as long as our common stock continues to be regularly traded on an established securities market, only a non-U.S. holder that actually or constructively owns, or owned at any time during the shorter of the five-year period ending on the date of the disposition or the non-U.S. holder’s holding period for the common stock, more than 5% of our common stock will be taxable on gain recognized on the disposition of our common stock as a result of our status as a USRPHC. If our common stock ceased to be regularly traded on an established securities market prior to the beginning of the calendar year in which the relevant disposition occurred, all non-U.S. holders generally would be subject to U.S. federal income tax on a taxable disposition of our common stock, and a 15% withholding tax would apply to the gross proceeds from the sale of our common stock by such non-U.S. holders.

Non-U.S. holders should consult their tax advisors with respect to the application of the foregoing rules to their ownership and disposition of our common stock.

Backup withholding and information reporting

Any dividends paid to a non-U.S. holder must be reported annually to the IRS and to the non-U.S. holder. Copies of these information returns may be made available to the tax authorities in the country in which the non-U.S. holder resides or is established. Payments of dividends to a non-U.S. holder generally will not be subject to backup withholding if the non-U.S. holder establishes an exemption by properly certifying its non-U.S. status on an IRS Form W-8BEN, IRS Form W-8BEN-E or other appropriate version of IRS Form W-8.

Payments of the proceeds from a sale or other disposition by a non-U.S. holder of our common stock effected by or through a U.S. office of a broker generally will be subject to information reporting and backup withholding (at the applicable rate) unless the non-U.S. holder establishes an exemption by properly certifying its non-U.S. status on an IRS Form W-8BEN, IRS Form W-8BEN-E or other appropriate version of IRS Form W-8 and certain other conditions are met. Information reporting and backup withholding generally will not apply to any payment of the proceeds from a sale or other disposition of our common stock effected outside the United States by a non-U.S. office of a broker. However, unless such broker has documentary evidence in its records that the holder is not a United States person and certain other conditions are met, or the non-U.S. holder otherwise establishes an exemption, information reporting will apply to a payment of the proceeds of the disposition of our common stock effected outside the United States by such a broker if it has certain relationships within the United States.

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Backup withholding is not an additional tax. Rather, the U.S. income tax liability (if any) of persons subject to backup withholding will be reduced by the amount of tax withheld. If withholding results in an overpayment of taxes, a refund may be obtained, provided that the required information is timely furnished to the IRS.

Additional withholding requirements under FATCA

Sections 1471 through 1474 of the Code, and the Treasury regulations and administrative guidance issued thereunder (“FATCA”), impose a 30% withholding tax on any dividends paid on our common stock and on the gross proceeds from a disposition of our common stock (if such disposition occurs after December 31, 2018), in each case if paid to a “foreign financial institution” or a “non-financial foreign entity” (each as defined in the Code) (including, in some cases, when such foreign financial institution or non-financial foreign entity is acting as an intermediary), unless (i) in the case of a foreign financial institution, such institution enters into an agreement with the U.S. government to withhold on certain payments, and to collect and provide to the U.S. tax authorities substantial information regarding U.S. account holders of such institution (which includes certain equity and debt holders of such institution, as well as certain account holders that are non-U.S. entities with U.S. owners), (ii) in the case of a non-financial foreign entity, such entity certifies that it does not have any “substantial United States owners” (as defined in the Code) or provides the applicable withholding agent with a certification identifying the direct and indirect substantial United States owners of the entity (in either case, generally on an IRS Form W-8BEN-E) or (iii) the foreign financial institution or non-financial foreign entity otherwise qualifies for an exemption from these rules and provides appropriate documentation (such as an IRS Form W-8BEN-E). Foreign financial institutions located in jurisdictions that have an intergovernmental agreement with the United States governing these rules may be subject to different rules. Under certain circumstances, a holder might be eligible for refunds or credits of such taxes.

INVESTORS CONSIDERING THE PURCHASE OF OUR COMMON STOCK ARE URGED TO CONSULT THEIR OWN TAX ADVISORS REGARDING THE APPLICATION OF THE U.S. FEDERAL INCOME TAX LAWS TO THEIR PARTICULAR SITUATIONS AND THE APPLICABILITY AND EFFECT OF U.S. FEDERAL ESTATE AND GIFT TAX LAWS AND ANY STATE, LOCAL OR NON-U.S. TAX LAWS AND TAX TREATIES.

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Underwriting

Under the terms and subject to the conditions contained in an underwriting agreement between us and J.P. Morgan Securities LLC and Goldman, Sachs & Co., as representatives of the underwriters in this offering, we have agreed to sell to the underwriters named below, and the underwriters have agreed, severally and not jointly, to buy the following number of shares of common stock set forth opposite their names:

Underwriters	Number of shares
J.P. Morgan Securities LLC		25,549,407
Goldman, Sachs & Co.		9,935,881
Wells Fargo Securities, LLC		1,526,796
RBC Capital Markets, LLC		1,251,472
Citigroup Global Markets Inc.		1,251,472
Morgan Stanley & Co. LLC		1,251,472
Deutsche Bank Securities Inc.		425,500
BBVA Securities Inc.		425,500
BOK Financial Securities, Inc.		425,500
BB&T Capital Markets, a division of BB&T Securities, LLC		425,500
BTIG, LLC		425,500
Capital One Securities, Inc.		425,500
CIBC World Markets Corp.		425,500
Citizens Capital Markets, Inc.		425,500
Comerica Securities, Inc.		425,500
Credit Suisse Securities (USA) LLC		425,500
Evercore Group L.L.C.		425,500
Heikkinen Energy Securities, LLC		425,500
IBERIA Capital Partners L.L.C.		425,500
ING Financial Markets LLC		425,500
Johnson Rice & Company L.L.C.		425,500
Tudor, Pickering, Holt & Co. Securities, Inc.		425,500
Regions Securities LLC		425,500
Total		48,000,000

The underwriting agreement provides that the underwriters are obligated to purchase all the shares of common stock in this offering if any are purchased, other than those shares covered by the underwriters’ option to purchase additional common stock. We have granted the underwriters a 30-day option to purchase on a pro rata basis up to an aggregate of 7,200,000 additional shares at the offering price set forth on the cover page of this prospectus supplement. The offering of the shares by the underwriters is subject to receipt and acceptance and subject to the underwriters’ right to reject any order in whole or in part.

The underwriters have proposed initially to offer the shares to the public at the public offering price set forth on the cover page of this prospectus and to dealers at that price less a concession not in excess of $0.05 per share. After the initial offering, the public offering price, concession or any other term of the offering may be changed.

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The following table shows the public offering price, underwriting discount and proceeds before expenses to us. The information assumes either no exercise or full exercise by the underwriters of their option to purchase additional shares.

	Per Share		Without option		With option
Public offering price	$	10.8000	$	518,400,000	$	596,160,000
Underwriting discounts	$	0.2154	$	10,339,200	$	11,890,080
Proceeds to us before expenses	$	10.5846	$	508,060,800	$	584,269,920

We estimate that our out-of-pocket expenses for this offering will be approximately $250,000.

We have agreed to indemnify the several underwriters against liabilities under the Securities Act, or contribute to payments that the underwriters may be required to make in that respect. The underwriters have informed us that they do not expect sales to accounts over which they have discretionary authority to exceed 5% of the shares of common stock being offered.

Lock-Up agreements

We have agreed that we will not (1) offer, pledge, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant to purchase, lend, or otherwise transfer or dispose of, directly or indirectly, any shares of our common stock beneficially owned under Section 16 of the Exchange Act, (2) enter into any swap or other arrangement that transfers to another, in whole or in part, any of the economic consequences of ownership of the our common stock, whether any such transaction is to be settled by delivery of common stock or such other securities, in cash or otherwise, or (3) file any registration statement with the Commission relating to the offering of any shares of our common stock or any securities convertible into or exercisable or exchangeable for common stock or (4) publicly announce the intention to effect any such transaction described in the preceding clauses, without the prior written consent of J.P. Morgan Securities LLC and Goldman, Sachs & Co. for a period of 60 days after the date of this prospectus supplement (the “Restricted Period”).

The restrictions contained in the preceding paragraph shall not apply to (a) the shares of common stock to be sold pursuant to this prospectus supplement, (b) the issuance by us of shares of common stock upon the exercise of an option or warrant or the conversion of a security outstanding on the date hereof, (c) the issuance by us of restricted shares of common stock or other equity awards, in each case, not exercisable or transferrable during the Restricted Period, pursuant to our 2010 Annual Incentive Compensation Plan, or (d) the establishment of a trading plan pursuant to Rule 10b5-1 under the Exchange Act for the transfer of shares of our common stock, provided that (i) such plan does not provide for the transfer of shares of our common stock during the Restricted Period and (ii) to the extent a public announcement or filing under the Exchange Act, if any, is required of or voluntarily made by or on our behalf regarding the establishment of such plan, such announcement or filing shall include a statement to the effect that no transfer of shares of our common stock may be made under such plan during the Restricted Period.

In addition, during the Restricted Period, our directors and executive officers have agreed that they will not, without the prior written consent of J.P. Morgan Securities LLC and Goldman, Sachs & Co., (1) offer, pledge, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant to purchase, lend, or otherwise transfer or dispose of, directly or indirectly, any shares of our common stock beneficially owned (as such term is used in Rule 13d-3 of the Exchange Act), or (2) enter into any swap or other arrangement that transfers to another, in whole or in part, any of the economic consequences of ownership of shares of our common stock, whether any such transaction described in clause

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(1) or (2) above is to be settled by delivery of shares of our common stock or such other securities, in cash or otherwise. These lockup agreements are subject to certain exceptions, including (a) transactions relating to shares of our common stock or other securities acquired in open market transactions after the completion of the public offering of our common shares to which this prospectus supplement relates, provided that no filing under Section 16(a) of the Exchange Act, shall be required or shall be voluntarily made in connection with subsequent sales of shares of our common stock or other securities acquired in such open market transactions, (b) transfers of shares of our common stock or any security convertible into shares of our common stock as a bona fide gift; provided that in the case of any transfer pursuant to clause (b), no filing under Section 16(a) of the Exchange Act, reporting a reduction in beneficial ownership of shares of our common stock, shall be required or shall be voluntarily made during the Restricted Period, (c) distributions of shares of our common stock or any security convertible into common stock to limited partners, members or stockholders of the undersigned; provided that in the case of any distribution pursuant to clause (c), (i) each distributee shall sign and deliver a lock-up letter and (ii) no filing under Section 16(a) of the Exchange Act, reporting a reduction in beneficial ownership of shares of our common stock, shall be required or shall be voluntarily made during the Restricted Period, (d) the establishment of a trading plan pursuant to Rule 10b5-1 under the Exchange Act for the transfer of shares of our common stock, provided that (i) such plan does not provide for the transfer of shares of our common stock during the Restricted Period and (ii) to the extent a public announcement or filing under the Exchange Act, if any, is required of or voluntarily made by or on behalf of our directors or applicable officers or the Company regarding the establishment of such plan, such announcement or filing shall include a statement to the effect that no transfer of shares of our common stock may be made under such plan during the Restricted Period, or (e) transfers of no more than an aggregate of 200,000 shares of common stock.

J.P. Morgan Securities LLC and Goldman, Sachs & Co., in their discretion, may release the shares of our common stock and other securities subject to the lock-up agreements described above in whole or in part at any time. When determining whether or not to release the common stock and other securities from lock-up agreements, J.P. Morgan Securities LLC and Goldman, Sachs & Co. will consider, among other factors, the holder’s reasons for requesting the release and the number of shares of common stock or other securities for which the release is being requested.

Other relationships

The underwriters and their affiliates are full service financial institutions engaged in various activities, which may include securities trading, commercial and investment banking, financial advisory, investment management, investment research, principal investment hedging, financing and brokerage activities. The underwriters and their affiliates have from time to time performed, and may in the future perform, various financial advisory, commercial banking and investment banking services for us and for our affiliates in the ordinary course of business for which they have received and would receive customary compensation. In addition, affiliates of certain of the underwriters are lenders under our revolving credit facility.

In the ordinary course of their various business activities, the underwriters and their affiliates may make or hold a broad array of investments and actively trade debt and equity securities (or related derivative securities) and financial instruments (including bank loans) for their own account and for the accounts of their customers, and such investments and securities activities may involve securities and/or instruments of the issuer. The underwriters and their affiliates may also make investment recommendations and/or publish or express independent research views in respect of such securities or instruments and may at any time hold, or recommend to clients that they acquire, long and/or short positions in such securities and instruments.

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Stabilization

In connection with this offering each underwriter may engage in stabilizing transactions, over-allotment transactions, syndicate covering transactions, penalty bids and passive market making in accordance with Regulation M under the Exchange Act. These stabilizing transactions, syndicate covering transactions and penalty bids may have the effect of raising or maintaining the market price of our common stock or preventing or retarding a decline in the market price of the common stock. As a result the price of our common stock may be higher than the price that might otherwise exist in the open market. These transactions may be effected on the New York Stock Exchange or otherwise and, if commenced, may be discontinued at any time.

• Stabilizing transactions permit bids to purchase the underlying security so long as the stabilizing bids do not exceed a specified maximum.

• Over-allotment involves sales by the underwriter of shares in excess of the number of shares the underwriter is obligated to purchase, which creates a syndicate short position. The short position may be either a covered short position or a naked short position. In a covered short position, the number of shares over-allotted by the underwriter is not greater than the number of shares that it may purchase in the over-allotment option. In a naked short position, the number of shares involved is greater than the number of shares in the over-allotment option. The underwriter may close out any covered short position by either exercising its over-allotment option and/or purchasing shares in the open market.

• Syndicate covering transactions involve purchases of the common stock in the open market after the distribution has been completed in order to cover syndicate short positions. In determining the source of shares to close out the short position, the underwriter will consider, among other things, the price of shares available for purchase in the open market as compared to the price at which it may purchase shares through the over-allotment option. If the underwriter sells more shares than could be covered by the over-allotment option, a naked short position, the position can only be closed out by buying shares in the open market. A naked short position is more likely to be created if the underwriter is concerned that there could be downward pressure on the price of the shares in the open market after pricing that could adversely affect investors who purchase in the offering.

• Penalty bids permit the underwriter to reclaim a selling concession from a syndicate member when the common stock originally sold by the syndicate member is purchased in a stabilizing or syndicate covering transaction to cover syndicate short positions.

• In passive market making, market makers in the common stock who are underwriters or prospective underwriters may, subject to limitations, make bids for or purchases of our common stock until the time, if any, at which a stabilizing bid is made.

These stabilizing transactions, syndicate covering transactions and penalty bids may have the effect of raising or maintaining the market price of our common stock or preventing or retarding a decline in the market price of the common stock. As a result the price of our common stock may be higher than the price that might otherwise exist in the open market. These transactions may be effected on the New York Stock Exchange or otherwise and, if commenced, may be discontinued at any time.

Electronic prospectus

A prospectus supplement and the accompanying prospectus in electronic format may be made available on web sites maintained by the underwriters participating in this offering and the underwriters participating in this offering may distribute prospectuses electronically. The underwriters may agree to allocate a number of shares to selling group members for sale to their online brokerage account holders. Internet distributions will be allocated by underwriters that will make internet distributions on the same basis as other allocations.

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Selling restrictions

EEA restriction

In relation to each Member State of the European Economic Area which has implemented the Prospectus Directive (each, a “Relevant Member State”) an offer to the public of any shares which are the subject of the offering contemplated by this prospectus (the “Shares”) may not be made in that Relevant Member State except that an offer to the public in that Relevant Member State of any Shares may be made at any time under the following exemptions under the Prospectus Directive, if they have been implemented in that Relevant Member State:

(a) to legal entities which are qualified investors as defined under the Prospectus Directive;

(b) by the underwriter to fewer than 100, or, if the Relevant Member State has implemented the relevant provisions of the 2010 PD Amending Directive, 150, natural or legal persons (other than qualified investors as defined in the Prospectus Directive), as permitted under the Prospectus Directive; or

(c) in any other circumstances falling within Article 3(2) of the Prospectus Directive,

provided that no such offer of Shares shall result in a requirement for the Company or any underwriter to publish a prospectus pursuant to Article 3 of the Prospectus Directive or supplement a prospectus pursuant to Article 16 of the Prospectus Directive.

For the purposes of this provision, the expression an “offer to the public” in relation to any Shares in any Relevant Member State means the communication in any form and by any means of sufficient information on the terms of the offer and any Shares to be offered so as to enable an investor to decide to purchase any Shares, as the same may be varied in that Member State by any measure implementing the Prospectus Directive in that Member State, the expression “Prospectus Directive” means Directive 2003/71/EC (and amendments thereto, including the 2010 PD Amending Directive, to the extent implemented in the Relevant Member State), and includes any relevant implementing measure in each Relevant Member State and the expression “2010 PD Amending Directive” means Directive 2010/73/EU.

United Kingdom

Each underwriter has represented and agreed that:

(a) it has only communicated or caused to be communicated and will only communicate or cause to be communicated an invitation or inducement to engage in investment activity (within the meaning of Section 21 of the Financial Services and Markets Act 2000 (the “FSMA”)) received by it in connection with the issue or sale of the shares in circumstances in which Section 21(1) of the FSMA does not apply to the Company; and

(b) it has complied and will comply with all applicable provisions of the FSMA with respect to anything done by it in relation to the shares in, from or otherwise involving the United Kingdom.

Notice to United Kingdom investors

This prospectus is only being distributed to and is only directed at (i) persons who are outside the United Kingdom or (ii) investment professionals falling within Article 19(5) of the Financial Services and Markets Act 2000 (Financial Promotion) Order 2005 (the “Order”) or (iii) high net worth companies, and other persons to whom it may lawfully be communicated, falling within Article 49(2)(a) to (d) of the Order (all such persons together being referred to as “relevant persons”). The Shares are only available to, and any invitation, offer or agreement to subscribe, purchase or otherwise acquire such Shares will be engaged in only with, relevant persons. Any person who is not a relevant person should not act or rely on this document or any of its contents.

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Notice to residents of Canada

The distribution of the shares in Canada is being made only in the provinces of Ontario and Quebec on a private placement basis such that the shares may be sold only to purchasers resident in those provinces purchasing as principal that are both ‘‘accredited investors’’ as defined in National Instrument 45-106 Prospectus and Registration Exemptions and ‘‘permitted clients’’ as defined in National Instrument 31-103 Registration Requirements, Exemptions and Ongoing Registrant Obligations. Any resale of the shares must be made in accordance with an exemption from the prospectus requirements and in compliance with the registration requirements of applicable securities laws.

Switzerland

This document is not intended to constitute an offer or solicitation to purchase or invest in the shares described herein. The shares may not be publicly offered, sold or advertised, directly or indirectly, in, into or from Switzerland and will not be listed on the SIX Swiss Exchange or on any other exchange or regulated trading facility in Switzerland. Neither this document nor any other offering or marketing material relating to the shares constitutes a prospectus as such term is understood pursuant to article 652a or article 1156 of the Swiss Code of Obligations or a listing prospectus within the meaning of the listing rules of the SIX Swiss Exchange or any other regulated trading facility in Switzerland, and neither this document nor any other offering or marketing material relating to the shares may be publicly distributed or otherwise made publicly available in Switzerland.

Neither this document nor any other offering or marketing material relating to the offering, nor the Company nor the shares have been or will be filed with or approved by any Swiss regulatory authority. The shares are not subject to the supervision by any Swiss regulatory authority, e.g., the Swiss Financial Markets Supervisory Authority FINMA (FINMA), and investors in the shares will not benefit from protection or supervision by such authority.

Hong Kong

The shares may not be offered or sold by means of any document other than (i) in circumstances which do not constitute an offer to the public within the meaning of the Companies Ordinance (Cap.32, Laws of Hong Kong), or (ii) to “professional investors” within the meaning of the Securities and Futures Ordinance (Cap.571, Laws of Hong Kong) and any rules made thereunder, or (iii) in other circumstances which do not result in the document being a “prospectus” within the meaning of the Companies Ordinance (Cap.32, Laws of Hong Kong), and no advertisement, invitation or document relating to the shares may be issued or may be in the possession of any person for the purpose of issue (in each case whether in Hong Kong or elsewhere), which is directed at, or the contents of which are likely to be accessed or read by, the public in Hong Kong (except if permitted to do so under the laws of Hong Kong) other than with respect to shares which are or are intended to be disposed of only to persons outside Hong Kong or only to “professional investors” within the meaning of the Securities and Futures Ordinance (Cap. 571, Laws of Hong Kong) and any rules made thereunder.

Singapore

This prospectus has not been registered as a prospectus with the Monetary Authority of Singapore. Accordingly, this prospectus and any other document or material in connection with the offer or sale, or invitation for subscription or purchase, of the shares may not be circulated or distributed, nor may the shares be offered or sold, or be made the subject of an invitation for subscription or purchase, whether directly or indirectly, to persons in Singapore other than (i) to an institutional investor under Section 274 of the Securities and Futures

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Act, Chapter 289 of Singapore (the “SFA”), (ii) to a relevant person, or any person pursuant to Section 275(1A), and in accordance with the conditions, specified in Section 275 of the SFA or (iii) otherwise pursuant to, and in accordance with the conditions of, any other applicable provision of the SFA.

Where the shares are subscribed or purchased under Section 275 by a relevant person which is: (a) a corporation (which is not an accredited investor) the sole business of which is to hold investments and the entire share capital of which is owned by one or more individuals, each of whom is an accredited investor; or (b) a trust (where the trustee is not an accredited investor) whose sole purpose is to hold investments and each beneficiary is an accredited investor, shares, debentures and units of shares and debentures of that corporation or the beneficiaries’ rights and interest in that trust shall not be transferable for 6 months after that corporation or that trust has acquired the shares under Section 275 except: (1) to an institutional investor under Section 274 of the SFA or to a relevant person, or any person pursuant to Section 275(1A), and in accordance with the conditions, specified in Section 275 of the SFA; (2) where no consideration is given for the transfer; or (3) by operation of law.

Japan

The securities have not been and will not be registered under the Financial Instruments and Exchange Law of Japan (the Financial Instruments and Exchange Law) and each underwriter has agreed that it will not offer or sell any securities, directly or indirectly, in Japan or to, or for the benefit of, any resident of Japan (which term as used herein means any person resident in Japan, including any corporation or other entity organized under the laws of Japan), or to others for re-offering or resale, directly or indirectly, in Japan or to a resident of Japan, except pursuant to an exemption from the registration requirements of, and otherwise in compliance with, the Financial Instruments and Exchange Law and any other applicable laws, regulations and ministerial guidelines of Japan.

Legal matters

Certain legal matters in connection with the common stock will be passed upon by Vinson & Elkins L.L.P., Houston, Texas, as our counsel. Certain legal matters will be passed upon for the underwriters by Kirkland & Ellis LLP, Houston, Texas.

Experts

The consolidated financial statements and management’s assessment of the effectiveness of internal control over financial reporting (which is included in Management’s Report on Internal Control over Financial Reporting) incorporated in this prospectus supplement by reference to the Annual Report on Form 10-K for the year ended December 31, 2015 have been so incorporated in reliance on the report of PricewaterhouseCoopers LLP, an independent registered public accounting firm, given on the authority of said firm as experts in auditing and accounting.

Certain estimates of our net crude oil and natural gas reserves and related information included or incorporated by reference in this prospectus supplement have been derived from reports prepared by DeGolyer and MacNaughton. All such information has been so included or incorporated by reference on the authority of such firm as an expert in such matters.

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PROSPECTUS

Oasis Petroleum Inc.

Debt Securities

Preferred Stock

Common Stock

Depositary Shares

Warrants

Guarantee of Debt Securities of Oasis Petroleum Inc. by:

Oasis Midstream Services LLC

Oasis Petroleum LLC

Oasis Petroleum Marketing LLC

Oasis Petroleum North America LLC

Oasis Well Services LLC

We may offer and sell the securities listed above from time to time in one or more offerings in one or more classes or series. Any debt securities we offer pursuant to this prospectus may be fully and unconditionally guaranteed by certain of our subsidiaries, including Oasis Midstream Services LLC, Oasis Petroleum LLC, Oasis Petroleum Marketing LLC, Oasis Petroleum North America LLC, and Oasis Well Services LLC.

This prospectus provides you with a general description of the securities that may be offered. Each time securities are offered, we will provide a prospectus supplement and attach it to this prospectus. The prospectus supplement will contain more specific information about the offering and the terms of the securities being offered, including any guarantees by our subsidiaries. A prospectus supplement may also add, update or change information contained in this prospectus. This prospectus may not be used to offer or sell securities without a prospectus supplement describing the method and terms of the offering.

We may sell these securities directly or through agents, underwriters or dealers, or through a combination of these methods. See “Plan of Distribution.” The prospectus supplement will list any agents, underwriters or dealers that may be involved and the compensation they will receive. The prospectus supplement will also show you the total amount of money that we will receive from selling the securities being offered, after the expenses of the offering. You should carefully read this prospectus and any accompanying prospectus supplement, together with the documents we incorporate by reference, before you invest in any of our securities.

Investing in any of our securities involves risk. Please read carefully the information included and incorporated by reference in this prospectus and in any applicable prospectus supplement for a discussion of the factors you should consider before deciding to purchase our securities. See “Risk Factors” on page 5 of this prospectus.

Our common stock is listed on the New York Stock Exchange (“NYSE”) under the symbol “OAS.”

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

This prospectus is dated July 15, 2014.

TABLE OF CONTENTS

ABOUT THIS PROSPECTUS	1
THE COMPANY	1
WHERE YOU CAN FIND MORE INFORMATION	2
CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS	3
RISK FACTORS	5
RATIO OF EARNINGS TO FIXED CHARGES	5
USE OF PROCEEDS	5
DESCRIPTION OF DEBT SECURITIES	6
DESCRIPTION OF CAPITAL STOCK	18
DESCRIPTION OF WARRANTS	22
PLAN OF DISTRIBUTION	23
LEGAL MATTERS	25
EXPERTS	25

You should rely only on the information contained in or incorporated by reference into this prospectus and any prospectus supplement. We have not authorized any dealer, salesman or other person to provide you with additional or different information. If anyone provides you with different or inconsistent information, you should not rely on it. This prospectus and any prospectus supplement are not an offer to sell or the solicitation of an offer to buy any securities other than the securities to which they relate and are not an offer to sell or the solicitation of an offer to buy securities in any jurisdiction to any person to whom it is unlawful to make an offer or solicitation in that jurisdiction. You should not assume that the information contained in this prospectus is accurate as of any date other than the date on the front cover of this prospectus, or that the information contained in any document incorporated by reference is accurate as of any date other than the date of the document incorporated by reference, regardless of the time of delivery of this prospectus or any sale of a security.

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ABOUT THIS PROSPECTUS

This prospectus is part of a registration statement that we filed with the Securities and Exchange Commission, which we refer to as the SEC, using a “shelf” registration process. Under this shelf registration process, we may offer and sell any combination of the securities described in this prospectus in one or more offerings. This prospectus provides you with a general description of the securities we may offer. Each time we sell securities, we will provide you with this prospectus and a prospectus supplement that will contain specific information about the terms of the offering and the offered securities. That prospectus supplement may also add, update or change information contained in this prospectus. Any statement that we make in this prospectus will be modified or superseded by any inconsistent statement made by us in a prospectus supplement.

Additional information, including our financial statements and the notes thereto, is incorporated in this prospectus by reference to our reports filed with the SEC. Please read “Where You Can Find More Information” below. You are urged to read this prospectus carefully, including the “Risk Factors,” and our reports filed with the SEC in their entirety before investing in our securities.

Unless the context requires otherwise or unless otherwise noted, all references in this prospectus or any accompanying prospectus supplement to “Oasis,” “we” or “our” are to Oasis Petroleum Inc. and its subsidiaries.

THE COMPANY

We are an independent exploration and production company focused on the acquisition and development of unconventional oil and natural gas resources primarily in the Williston Basin. Since our inception, we have emphasized the acquisition of properties that provide current production and significant upside potential through further development. Our drilling activity is primarily directed toward projects that we believe can provide us with repeatable successes in the Bakken and Three Forks formations.

Our principal executive offices are located at 1001 Fannin Street, Suite 1500, Houston, Texas 77002, and our telephone number at that address is (281) 404-9500. Our common stock is listed on NYSE under the symbol “OAS.”

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WHERE YOU CAN FIND MORE INFORMATION

We file annual, quarterly and current reports and other information with the SEC (File No. 001-34776) pursuant to the Securities Exchange Act of 1934 (the “Exchange Act”). You may read and copy any documents that are filed at the SEC’s public reference room at 100 F Street, N.E., Washington, D.C. 20549. You may also obtain copies of these documents at prescribed rates from the public reference section of the SEC at its Washington address. Please call the SEC at 1-800-SEC-0330 for further information.

Our filings are also available to the public through the SEC’s website at http://www.sec.gov.

The SEC allows us to “incorporate by reference” information that we file with it, which means that we can disclose important information to you by referring you to documents previously filed with the SEC. The information incorporated by reference is an important part of this prospectus, and the information that we later file with the SEC will automatically update and supersede this information. The following documents we filed with the SEC pursuant to the Exchange Act are incorporated herein by reference:

• our Annual Report on Form 10-K for the year ended December 31, 2013;

• our Quarterly Report on Form 10-Q for the quarter ended March 31, 2014;

• our Current Reports on Form 8-K filed on each of April 1, 2014 and May 6, 2014 (excluding any information furnished pursuant to Item 2.02 or Item 7.01 of any such Current Report on Form 8-K); and

• the description of our common stock contained in our registration statement on Form 8-A12B filed on June 14, 2010, including any amendment to that form that we may file in the future for the purpose of updating the description of our common stock.

These reports contain important information about us, our financial condition and our results of operations.

All future documents filed pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act (excluding any information furnished pursuant to Item 2.02 or Item 7.01 on any Current Report on Form 8-K) before the termination of each offering under this prospectus shall be deemed to be incorporated in this prospectus by reference and to be a part hereof from the date of filing of such documents. Any statement contained herein, or in a document incorporated or deemed to be incorporated by reference herein, shall be deemed to be modified or superseded for purposes of this prospectus to the extent that a statement contained herein or in any subsequently filed document that also is or is deemed to be incorporated by reference herein, modifies or supersedes such statement. Any such statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this prospectus.

You may request a copy of these filings at no cost by writing or telephoning us at the following address and telephone number:

Oasis Petroleum Inc.

1001 Fannin Street, Suite 1500

Houston, Texas 77002

Attention: General Counsel

(281) 404-9500

We also maintain a website at http://www.oasispetroleum.com. However, the information on our website is not part of this prospectus.

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CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus and the documents incorporated by reference contain forward-looking statements intended to qualify for the safe harbors from liability established by the Private Securities Litigation Reform Act of 1995, Section 27A of the Securities Act and Section 21E of the Exchange Act. These forward-looking statements are subject to a number of risks and uncertainties, many of which are beyond our control. All statements, other than statements of historical fact included in this prospectus and the documents incorporated by reference, regarding our strategy, future operations, financial position, estimated revenues and losses, projected costs, prospects, plans and objectives of management are forward-looking statements. When used in this prospectus, the words “could,” “believe,” “anticipate,” “intend,” “estimate,” “expect,” “may,” “continue,” “predict,” “potential,” “project” and similar expressions are intended to identify forward-looking statements, although not all forward-looking statements contain such identifying words. When considering forward-looking statements, you should keep in mind the risk factors and other cautionary statements described under the headings “Risk Factors” included in our most recent Annual Report on Form 10-K, any subsequently filed Quarterly Reports on Form 10-Q and any subsequently filed Current Reports on Form 8-K, all of which are incorporated by reference in this prospectus, and any risk factors included in an applicable prospectus supplement. Please read “Risk Factors” in this prospectus.

These forward-looking statements are based on management’s current belief, based on currently available information, as to the outcome and timing of future events. Without limiting the generality of the foregoing, certain statements incorporated by reference or included in this prospectus constitute forward-looking statements.

Forward-looking statements may include statements about:

• our business strategy;

• estimated future net reserves and present value thereof;

• timing and amount of future production of oil and natural gas;

• drilling and completion of wells;

• estimated inventory of wells remaining to be drilled and completed;

• costs of exploiting and developing our properties and conducting other operations;

• availability of drilling, completion and production equipment and materials;

• availability of qualified personnel;

• owning and operating well services and midstream companies;

• infrastructure for salt water disposal;

• gathering, transportation and marketing of oil and natural gas, both in the Williston Basin and other regions in the United States;

• property acquisitions;

• integration and benefits of property acquisitions, or the effects of such acquisitions on our cash position and levels of indebtedness;

• the amount, nature and timing of capital expenditures;

• availability and terms of capital;

• our financial strategy, budget, projections, execution of business plan and operating results;

• cash flows and liquidity;

• oil and natural gas realized prices;

• general economic conditions;

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• operating environment, including inclement weather conditions;

• effectiveness of risk management activities;

• competition in the oil and natural gas industry;

• counterparty credit risk;

• environmental liabilities;

• governmental regulation and the taxation of the oil and natural gas industry;

• developments in oil-producing and natural gas-producing countries;

• technology;

• uncertainty regarding future operating results; and

• plans, objectives, expectations and intentions contained in this prospectus that are not historical.

All forward-looking statements speak only as of the date they are made. You should not place undue reliance on these forward-looking statements. Although we believe that our plans, intentions and expectations reflected in or suggested by the forward-looking statements we make in this prospectus and the documents incorporated by reference are reasonable, we can give no assurance that these plans, intentions or expectations will be achieved. We disclose important factors that could cause our actual results to differ materially from our expectations under the headings “Risk Factors” included in our most recent Annual Report on Form 10-K, any subsequently filed Quarterly Reports on Form 10-Q and any subsequently filed Current Reports on Form 8-K, all of which are incorporated by reference in this prospectus. Please read “Risk Factors” in this prospectus. These cautionary statements qualify all forward-looking statements attributable to us or persons acting on our behalf.

All subsequent written and oral forward-looking statements attributable to us or to persons acting on our behalf are expressly qualified in their entirety by the foregoing. We undertake no obligation to publicly update any forward-looking statement, whether written or oral, that may be made from time to time, whether as a result of new information, future developments or otherwise. See also “Where You Can Find More Information.”

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RISK FACTORS

An investment in our securities involves a significant degree of risk. Before you invest in our securities you should carefully consider those risk factors included in our most recent Annual Report on Form 10-K, any subsequently filed Quarterly Reports on Form 10-Q and any subsequently filed Current Reports on Form 8-K, which are incorporated herein by reference, and those risk factors that may be included in any applicable prospectus supplement, together with all of the other information included in this prospectus, any prospectus supplement and the documents we incorporate by reference, in evaluating an investment in our securities. If any of the risks discussed in the foregoing documents were to occur, our business, financial condition, results of operations and cash flows could be materially adversely affected. Please read “Cautionary Note Regarding Forward-Looking Statements.”

RATIO OF EARNINGS TO FIXED CHARGES

The following table sets forth our ratios of consolidated earnings to fixed charges for the periods presented:

	Year Ended December 31,										Three Months Ended March 31,
	2009		2010		2011		2012		2013		2014
Ratio of earnings to fixed charges (1)		—		9.72		4.74		4.29		4.20		7.46

(1) Due to our net pre-tax loss for the year ended December 31, 2009, the ratio coverage was less than 1:1. The Company would have needed additional earnings of $15.2 million for the year ended December 31, 2009 to achieve a coverage of 1:1.

For purposes of computing the ratio of earnings to fixed charges, “earnings” consists of pre-tax income from continuing operations before fixed charges. “Fixed charges” consists of interest expense, amortized capital expenses related to indebtedness and an estimate of interest within rental expense.

We had no preferred stock outstanding for any period presented, and accordingly, the ratio of earnings to combined fixed charges and preferred stock dividends is the same as the ratio of earnings to fixed charges.

USE OF PROCEEDS

Except as may be stated in any applicable prospectus supplement, we intend to use the net proceeds from any sales of securities by us under this prospectus for general corporate purposes, which may include repayment or refinancing of borrowings, working capital, capital expenditures, investments and acquisitions. Pending any specific application, we may initially invest funds in short-term marketable securities or apply them to repayments of indebtedness.

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DESCRIPTION OF DEBT SECURITIES

The Debt Securities will be either our senior debt securities (“Senior Debt Securities”) or our subordinated debt securities (“Subordinated Debt Securities”). We will issue the Senior Debt Securities under a Senior Indenture, dated as of November 10, 2011, among us, the Subsidiary Guarantors, and U.S. Bank National Association, as trustee. We will issue the Subordinated Debt Securities under a “Subordinated Indenture” to be executed in the future among us, the Subsidiary Guarantors of such Debt Securities, if any, and U.S. Bank National Association, or another entity, as trustee. U.S. Bank National Association or any successor, or any other entity with which we execute an indenture, in its capacity as trustee under either or both of the indentures, is referred to as the “Trustee” for purposes of this section. Together, the Senior Indenture and the Subordinated Indenture are called “Indentures.”

The Debt Securities may be issued from time to time in one or more series. The particular terms of each series that are offered by a prospectus supplement will be described in the prospectus supplement.

Unless the Debt Securities are guaranteed by our subsidiaries as described below, the rights of Oasis and our creditors, including holders of the Debt Securities, to participate in the assets of any subsidiary upon the latter’s liquidation or reorganization, will be subject to the prior claims of the subsidiary’s creditors, except to the extent that we may ourself be a creditor with recognized claims against such subsidiary.

We have summarized selected provisions of the Indentures below. The summary is not complete. The form of each Indenture has been filed with the SEC as an exhibit to the registration statement of which this prospectus is a part, and you should read the Indentures for provisions that may be important to you. Capitalized terms used in the summary have the meanings specified in the Indentures.

General

The Indentures provide that Debt Securities in separate series may be issued thereunder from time to time without limitation as to aggregate principal amount. We may specify a maximum aggregate principal amount for the Debt Securities of any series. We will determine the terms and conditions of the Debt Securities, including the maturity, principal and interest, but those terms must be consistent with the Indenture. The Debt Securities will be our unsecured obligations.

The Subordinated Debt Securities will be subordinated in right of payment to the prior payment in full of all of our Senior Debt (as defined) as described under “— Subordination of Subordinated Debt Securities” and in the prospectus supplement applicable to any Subordinated Debt Securities. If the prospectus supplement so indicates, the Debt Securities will be convertible into our common stock.

If specified in the prospectus supplement respecting a particular series of Debt Securities, certain subsidiaries of Oasis (each a “Subsidiary Guarantor”) will fully and unconditionally guarantee (the “Subsidiary Guarantee”) that series as described under “— Subsidiary Guarantee” and in the prospectus supplement. Each Subsidiary Guarantee will be an unsecured obligation of the Subsidiary Guarantor. A Subsidiary Guarantee of Subordinated Debt Securities will be subordinated to the Senior Debt of the Subsidiary Guarantor on the same basis as the Subordinated Debt Securities are subordinated to our Senior Debt.

The applicable prospectus supplement will set forth the price or prices at which the Debt Securities to be issued will be offered for sale and will describe the following terms of such Debt Securities:

(1) the title of the Debt Securities;

(2) whether the Debt Securities are Senior Debt Securities or Subordinated Debt Securities and, if Subordinated Debt Securities, the related subordination terms;

(3) whether any Subsidiary Guarantor will provide a Subsidiary Guarantee of the Debt Securities;

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(4) any limit on the aggregate principal amount of the Debt Securities;

(5) each date on which the principal of the Debt Securities will be payable;

(6) the interest rate that the Debt Securities will bear and the interest payment dates for the Debt Securities;

(7) each place where payments on the Debt Securities will be payable;

(8) any terms upon which the Debt Securities may be redeemed, in whole or in part, at our option;

(9) any sinking fund or other provisions that would obligate us to redeem or otherwise repurchase the Debt Securities;

(10) the portion of the principal amount, if less than all, of the Debt Securities that will be payable upon declaration of acceleration of the Maturity of the Debt Securities;

(11) whether the Debt Securities are defeasible;

(12) any addition to or change in the Events of Default;

(13) whether the Debt Securities are convertible into our common stock and, if so, the terms and conditions upon which conversion will be effected, including the initial conversion price or conversion rate and any adjustments thereto and the conversion period;

(14) any addition to or change in the covenants in the Indenture applicable to the Debt Securities; and

(15) any other terms of the Debt Securities not inconsistent with the provisions of the Indenture.

Debt Securities, including any Debt Securities that provide for an amount less than the principal amount thereof to be due and payable upon a declaration of acceleration of the Maturity thereof (“Original Issue Discount Securities”), may be sold at a substantial discount below their principal amount. Special United States federal income tax considerations applicable to Debt Securities sold at an original issue discount may be described in the applicable prospectus supplement. In addition, special United States federal income tax or other considerations applicable to any Debt Securities that are denominated in a currency or currency unit other than United States dollars may be described in the applicable prospectus supplement.

Subordination of Subordinated Debt Securities

The indebtedness evidenced by the Subordinated Debt Securities will, to the extent set forth in the Subordinated Indenture with respect to each series of Subordinated Debt Securities, be subordinated in right of payment to the prior payment in full of all of our Senior Debt, including the Senior Debt Securities, and it may also be senior in right of payment to all of our Subordinated Debt. The prospectus supplement relating to any Subordinated Debt Securities will summarize the subordination provisions of the Subordinated Indenture applicable to that series including:

• the applicability and effect of such provisions upon any payment or distribution respecting that series following any liquidation, dissolution or other winding-up, or any assignment for the benefit of creditors or other marshalling of assets or any bankruptcy, insolvency or similar proceedings;

• the applicability and effect of such provisions in the event of specified defaults with respect to any Senior Debt, including the circumstances under which and the periods during which we will be prohibited from making payments on the Subordinated Debt Securities; and

• the definition of Senior Debt applicable to the Subordinated Debt Securities of that series and, if the series is issued on a senior subordinated basis, the definition of Subordinated Debt applicable to that series.

The prospectus supplement will also describe as of a recent date the approximate amount of Senior Debt to which the Subordinated Debt Securities of that series will be subordinated.

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The failure to make any payment on any of the Subordinated Debt Securities by reason of the subordination provisions of the Subordinated Indenture described in the prospectus supplement will not be construed as preventing the occurrence of an Event of Default with respect to the Subordinated Debt Securities arising from any such failure to make payment.

The subordination provisions described above will not be applicable to payments in respect of the Subordinated Debt Securities from a defeasance trust established in connection with any legal defeasance or covenant defeasance of the Subordinated Debt Securities as described under “— Legal Defeasance and Covenant Defeasance.”

Subsidiary Guarantee

If specified in the prospectus supplement, one or more of the Subsidiary Guarantors will guarantee the Debt Securities of a series. Unless otherwise indicated in the prospectus supplement, the following provisions will apply to the Subsidiary Guarantee of the Subsidiary Guarantor.

Subject to the limitations described below and in the prospectus supplement, one or more of the Subsidiary Guarantors will jointly and severally, fully and unconditionally guarantee the punctual payment when due, whether at Stated Maturity, by acceleration or otherwise, of all our payment obligations under the Indentures and the Debt Securities of a series, whether for principal of, premium, if any, or interest on the Debt Securities or otherwise (all such obligations guaranteed by a Subsidiary Guarantor being herein called the “Guaranteed Obligations”). The Subsidiary Guarantors will also pay all expenses (including reasonable counsel fees and expenses) incurred by the applicable Trustee in enforcing any rights under a Subsidiary Guarantee with respect to a Subsidiary Guarantor.

In the case of Subordinated Debt Securities, a Subsidiary Guarantor’s Subsidiary Guarantee will be subordinated in right of payment to the Senior Debt of such Subsidiary Guarantor on the same basis as the Subordinated Debt Securities are subordinated to our Senior Debt. No payment will be made by any Subsidiary Guarantor under its Subsidiary Guarantee during any period in which payments by us on the Subordinated Debt Securities are suspended by the subordination provisions of the Subordinated Indenture.

Each Subsidiary Guarantee will be limited in amount to an amount not to exceed the maximum amount that can be guaranteed by the relevant Subsidiary Guarantor without rendering such Subsidiary Guarantee voidable under applicable law relating to fraudulent conveyance or fraudulent transfer or similar laws affecting the rights of creditors generally.

Each Subsidiary Guarantee will be a continuing guarantee and will:

(1) remain in full force and effect until either (a) payment in full of all the applicable Debt Securities (or such Debt Securities are otherwise satisfied and discharged in accordance with the provisions of the applicable Indenture) or (b) released as described in the following paragraph;

(2) be binding upon each Subsidiary Guarantor; and

(3) inure to the benefit of and be enforceable by the applicable Trustee, the Holders and their successors, transferees and assigns.

In the event that (a) a Subsidiary Guarantor ceases to be a Subsidiary, (b) either legal defeasance or covenant defeasance occurs with respect to the series or (c) all or substantially all of the assets or all of the Capital Stock of such Subsidiary Guarantor is sold, including by way of sale, merger, consolidation or otherwise, such Subsidiary Guarantor will be released and discharged of its obligations under its Subsidiary Guarantee without any further action required on the part of the Trustee or any Holder, and no other person acquiring or owning the assets or Capital Stock of such Subsidiary Guarantor will be required to enter into a Subsidiary Guarantee. In addition, the prospectus supplement may specify additional circumstances under which a Subsidiary Guarantor can be released from its Subsidiary Guarantee.

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Form, Exchange and Transfer

The Debt Securities of each series will be issuable only in fully registered form, without coupons, and, unless otherwise specified in the applicable prospectus supplement, only in denominations of $1,000 and integral multiples thereof.

At the option of the Holder, subject to the terms of the applicable Indenture and the limitations applicable to Global Securities, Debt Securities of each series will be exchangeable for other Debt Securities of the same series of any authorized denomination and of a like tenor and aggregate principal amount.

Subject to the terms of the applicable Indenture and the limitations applicable to Global Securities, Debt Securities may be presented for exchange as provided above or for registration of transfer (duly endorsed or with the form of transfer endorsed thereon duly executed) at the office of the Security Registrar or at the office of any transfer agent designated by us for such purpose. No service charge will be made for any registration of transfer or exchange of Debt Securities, but we may require payment of a sum sufficient to cover any tax or other governmental charge payable in that connection. Such transfer or exchange will be effected upon the Security Registrar or such transfer agent, as the case may be, being satisfied with the documents of title and identity of the person making the request. The Security Registrar and any other transfer agent initially designated by us for any Debt Securities will be named in the applicable prospectus supplement. We may at any time designate additional transfer agents or rescind the designation of any transfer agent or approve a change in the office through which any transfer agent acts, except that we will be required to maintain a transfer agent in each Place of Payment for the Debt Securities of each series.

If the Debt Securities of any series (or of any series and specified tenor) are to be redeemed in part, we will not be required to (1) issue, register the transfer of or exchange any Debt Security of that series (or of that series and specified tenor, as the case may be) during a period beginning at the opening of business 15 days before the day of mailing of a notice of redemption of any such Debt Security that may be selected for redemption and ending at the close of business on the day of such mailing or (2) register the transfer of or exchange any Debt Security so selected for redemption, in whole or in part, except the unredeemed portion of any such Debt Security being redeemed in part.

Global Securities

Some or all of the Debt Securities of any series may be represented, in whole or in part, by one or more Global Securities that will have an aggregate principal amount equal to that of the Debt Securities they represent. Each Global Security will be registered in the name of a Depositary or its nominee identified in the applicable prospectus supplement, will be deposited with such Depositary or nominee or its custodian and will bear a legend regarding the restrictions on exchanges and registration of transfer thereof referred to below and any such other matters as may be provided for pursuant to the applicable Indenture.

Notwithstanding any provision of the Indentures or any Debt Security described in this prospectus, no Global Security may be exchanged in whole or in part for Debt Securities registered, and no transfer of a Global Security in whole or in part may be registered, in the name of any Person other than the Depositary for such Global Security or any nominee of such Depositary unless:

(1) the Depositary has notified us that it is unwilling or unable to continue as Depositary for such Global Security or has ceased to be qualified to act as such as required by the applicable Indenture, and in either case we fail to appoint a successor Depositary within 90 days;

(2) an Event of Default with respect to the Debt Securities represented by such Global Security has occurred and is continuing and the Trustee has received a written request from the Depositary to issue certificated Debt Securities;

(3) subject to the rules of the Depositary, we shall have elected to terminate the book-entry system through the Depositary; or

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(4) other circumstances exist, in addition to or in lieu of those described above, as may be described in the applicable prospectus supplement.

All certificated Debt Securities issued in exchange for a Global Security or any portion thereof will be registered in such names as the Depositary may direct.

As long as the Depositary, or its nominee, is the registered holder of a Global Security, the Depositary or such nominee, as the case may be, will be considered the sole owner and Holder of such Global Security and the Debt Securities that it represents for all purposes under the Debt Securities and the applicable Indenture. Except in the limited circumstances referred to above, owners of beneficial interests in a Global Security will not be entitled to have such Global Security or any Debt Securities that it represents registered in their names, will not receive or be entitled to receive physical delivery of certificated Debt Securities in exchange for those interests and will not be considered to be the owners or Holders of such Global Security or any Debt Securities that is represents for any purpose under the Debt Securities or the applicable Indenture. All payments on a Global Security will be made to the Depositary or its nominee, as the case may be, as the Holder of the security. The laws of some jurisdictions may require that some purchasers of Debt Securities take physical delivery of such Debt Securities in certificated form. These laws may impair the ability to transfer beneficial interests in a Global Security.

Ownership of beneficial interests in a Global Security will be limited to institutions that have accounts with the Depositary or its nominee (“participants”) and to persons that may hold beneficial interests through participants. In connection with the issuance of any Global Security, the Depositary will credit, on its book-entry registration and transfer system, the respective principal amounts of Debt Securities represented by the Global Security to the accounts of its participants. Ownership of beneficial interests in a Global Security will be shown only on, and the transfer of those ownership interests will be effected only through, records maintained by the Depositary (with respect to participants’ interests) or any such participant (with respect to interests of Persons held by such participants on their behalf). Payments, transfers, exchanges and other matters relating to beneficial interests in a Global Security may be subject to various policies and procedures adopted by the Depositary from time to time. None of us, the Subsidiary Guarantors, the Trustees or the agents of us, the Subsidiary Guarantors or the Trustees will have any responsibility or liability for any aspect of the Depositary’s or any participant’s records relating to, or for payments made on account of, beneficial interests in a Global Security, or for maintaining, supervising or reviewing any records relating to such beneficial interests.

Payment and Paying Agents

Unless otherwise indicated in the applicable prospectus supplement, payment of interest on a Debt Security on any Interest Payment Date will be made to the Person in whose name such Debt Security (or one or more Predecessor Securities) is registered at the close of business on the Regular Record Date for such interest.

Unless otherwise indicated in the applicable prospectus supplement, principal of and any premium and interest on the Debt Securities of a particular series will be payable at the office of such Paying Agent or Paying Agents as we may designate for such purpose from time to time, except that at our option payment of any interest on Debt Securities in certificated form may be made by check mailed to the address of the Person entitled thereto as such address appears in the Security Register. Unless otherwise indicated in the applicable prospectus supplement, the corporate trust office of the Trustee under the Senior Indenture in The City of New York will be designated as sole Paying Agent for payments with respect to Senior Debt Securities of each series, and the corporate trust office of the Trustee under the Subordinated Indenture in The City of New York will be designated as the sole Paying Agent for payment with respect to Subordinated Debt Securities of each series. Any other Paying Agents initially designated by us for the Debt Securities of a particular series will be named in the applicable prospectus supplement. We may at any time designate additional Paying Agents or rescind the designation of any Paying Agent or approve a change in the office through which any Paying Agent acts, except that we will be required to maintain a Paying Agent in each Place of Payment for the Debt Securities of a particular series.

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All money paid by us to a Paying Agent for the payment of the principal of or any premium or interest on any Debt Security which remains unclaimed at the end of two years after such principal, premium or interest has become due and payable will be repaid to us, and the Holder of such Debt Security thereafter may look only to us for payment.

Consolidation, Merger and Sale of Assets

Unless otherwise specified in the prospectus supplement, we may not consolidate with or merge into, or transfer, lease or otherwise dispose of all or substantially all of our assets to, any Person (a “successor Person”), and may not permit any Person to consolidate with or merge into us, unless:

(1) the successor Person (if not us) is a corporation, partnership, trust or other entity organized and validly existing under the laws of any domestic jurisdiction and assumes our obligations on the Debt Securities and under the Indentures;

(2) immediately before and after giving pro forma effect to the transaction, no Event of Default, and no event which, after notice or lapse of time or both, would become an Event of Default, has occurred and is continuing; and

(3) several other conditions, including any additional conditions with respect to any particular Debt Securities specified in the applicable prospectus supplement, are met.

The successor Person (if not us) will be substituted for us under the applicable Indenture with the same effect as if it had been an original party to such Indenture, and, except in the case of a lease, we will be relieved from any further obligations under such Indenture and the Debt Securities.

Events of Default

Unless otherwise specified in the prospectus supplement, each of the following will constitute an Event of Default under the applicable Indenture with respect to Debt Securities of any series:

(1) failure to pay principal of or any premium on any Debt Security of that series when due, whether or not, in the case of Subordinated Debt Securities, such payment is prohibited by the subordination provisions of the Subordinated Indenture;

(2) failure to pay any interest on any Debt Securities of that series when due, continued for 30 days, whether or not, in the case of Subordinated Debt Securities, such payment is prohibited by the subordination provisions of the Subordinated Indenture;

(3) failure to deposit any sinking fund payment, when due, in respect of any Debt Security of that series, whether or not, in the case of Subordinated Debt Securities, such deposit is prohibited by the subordination provisions of the Subordinated Indenture;

(4) failure to perform or comply with the provisions described under “— Consolidation, Merger and Sale of Assets”;

(5) failure to perform any of our other covenants in such Indenture (other than a covenant included in such Indenture solely for the benefit of a series other than that series), continued for 60 days after written notice has been given by the applicable Trustee, or the Holders of at least 25% in principal amount of the Outstanding Debt Securities of that series, as provided in such Indenture;

(6) any Debt of ourself, any Significant Subsidiary or, if a Subsidiary Guarantor has guaranteed the series, such Subsidiary Guarantor, is not paid within any applicable grace period after final maturity or is accelerated by its holders because of a default and the total amount of such Debt unpaid or accelerated exceeds $20.0 million;

(7) any judgment or decree for the payment of money in excess of $20.0 million is entered against us, any Significant Subsidiary or, if a Subsidiary Guarantor has guaranteed the series, such Subsidiary Guarantor,

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remains outstanding for a period of 60 consecutive days following entry of such judgment and is not discharged, waived or stayed;

(8) certain events of bankruptcy, insolvency or reorganization affecting us, any Significant Subsidiary or, if a Subsidiary Guarantor has guaranteed the series, such Subsidiary Guarantor; and

(9) if any Subsidiary Guarantor has guaranteed such series, the Subsidiary Guarantee of any such Subsidiary Guarantor is held by a final non-appealable order or judgment of a court of competent jurisdiction to be unenforceable or invalid or ceases for any reason to be in full force and effect (other than in accordance with the terms of the applicable Indenture) or any Subsidiary Guarantor or any Person acting on behalf of any Subsidiary Guarantor denies or disaffirms such Subsidiary Guarantor’s obligations under its Subsidiary Guarantee (other than by reason of a release of such Subsidiary Guarantor from its Subsidiary Guarantee in accordance with the terms of the applicable Indenture).

If an Event of Default (other than an Event of Default with respect to Oasis Petroleum Inc. described in clause (8) above) with respect to the Debt Securities of any series at the time Outstanding occurs and is continuing, either the applicable Trustee or the Holders of at least 25% in principal amount of the Outstanding Debt Securities of that series by notice as provided in the Indenture may declare the principal amount of the Debt Securities of that series (or, in the case of any Debt Security that is an Original Issue Discount Security, such portion of the principal amount of such Debt Security as may be specified in the terms of such Debt Security) to be due and payable immediately, together with any accrued and unpaid interest thereon. If an Event of Default with respect to Oasis Petroleum Inc. described in clause (8) above with respect to the Debt Securities of any series at the time Outstanding occurs, the principal amount of all the Debt Securities of that series (or, in the case of any such Original Issue Discount Security, such specified amount) will automatically, and without any action by the applicable Trustee or any Holder, become immediately due and payable, together with any accrued and unpaid interest thereon. After any such acceleration and its consequences, but before a judgment or decree based on acceleration, the Holders of a majority in principal amount of the Outstanding Debt Securities of that series may, under certain circumstances, rescind and annul such acceleration if all Events of Default with respect to that series, other than the non-payment of accelerated principal (or other specified amount), have been cured or waived as provided in the applicable Indenture. For information as to waiver of defaults, see “— Modification and Waiver” below.

Subject to the provisions of the Indentures relating to the duties of the Trustees in case an Event of Default has occurred and is continuing, no Trustee will be under any obligation to exercise any of its rights or powers under the applicable Indenture at the request or direction of any of the Holders, unless such Holders have offered to such Trustee reasonable security or indemnity. Subject to such provisions for the indemnification of the Trustees, the Holders of a majority in principal amount of the Outstanding Debt Securities of any series will have the right to direct the time, method and place of conducting any proceeding for any remedy available to the Trustee or exercising any trust or power conferred on the Trustee with respect to the Debt Securities of that series.

No Holder of a Debt Security of any series will have any right to institute any proceeding with respect to the applicable Indenture, or for the appointment of a receiver or a trustee, or for any other remedy thereunder, unless:

(1) such Holder has previously given to the Trustee under the applicable Indenture written notice of a continuing Event of Default with respect to the Debt Securities of that series;

(2) the Holders of at least 25% in principal amount of the Outstanding Debt Securities of that series have made written request, and such Holder or Holders have offered reasonable security or indemnity, to the Trustee to institute such proceeding as trustee; and

(3) the Trustee has failed to institute such proceeding, and has not received from the Holders of a majority in principal amount of the Outstanding Debt Securities of that series a direction inconsistent with such request, within 60 days after such notice, request and offer.

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However, such limitations do not apply to a suit instituted by a Holder of a Debt Security for the enforcement of payment of the principal of or any premium or interest on such Debt Security on or after the applicable due date specified in such Debt Security or, if applicable, to convert such Debt Security.

We will be required to furnish to each Trustee annually a statement by certain of our officers as to whether or not we, to their knowledge, are in default in the performance or observance of any of the terms, provisions and conditions of the applicable Indenture and, if so, specifying all such known defaults.

Modification and Waiver

We may modify or amend an Indenture without the consent of any holders of the Debt Securities in certain circumstances, including:

(1) to evidence the succession under the Indenture of another Person to us or any Subsidiary Guarantor and to provide for its assumption of our or such Subsidiary Guarantor’s obligations to holders of Debt Securities;

(2) to make any changes that would add any additional covenants of us or the Subsidiary Guarantors for the benefit of the holders of Debt Securities or that do not adversely affect the rights under the Indenture of the Holders of Debt Securities in any material respect;

(3) to add any additional Events of Default;

(4) to provide for uncertificated notes in addition to or in place of certificated notes;

(5) to secure the Debt Securities;

(6) to establish the form or terms of any series of Debt Securities;

(7) to evidence and provide for the acceptance of appointment under the Indenture of a successor Trustee;

(8) to cure any ambiguity, defect or inconsistency;

(9) to add Subsidiary Guarantors; or

(10) in the case of any Subordinated Debt Security, to make any change in the subordination provisions that limits or terminates the benefits applicable to any Holder of Senior Debt.

Other modifications and amendments of an Indenture may be made by us, the Subsidiary Guarantors, if applicable, and the applicable Trustee with the consent of the Holders of a majority in principal amount of the Outstanding Debt Securities of each series affected by such modification or amendment; provided, however, that no such modification or amendment may, without the consent of the Holder of each Outstanding Debt Security affected thereby:

(1) change the Stated Maturity of the principal of, or any installment of principal of or interest on, any Debt Security;

(2) reduce the principal amount of, or any premium or interest on, any Debt Security;

(3) reduce the amount of principal of an Original Issue Discount Security or any other Debt Security payable upon acceleration of the Maturity thereof;

(4) change the place or currency of payment of principal of, or any premium or interest on, any Debt Security;

(5) impair the right to institute suit for the enforcement of any payment due on or any conversion right with respect to any Debt Security;

(6) modify the subordination provisions in the case of Subordinated Debt Securities, or modify any conversion provisions, in either case in a manner adverse to the Holders of the Subordinated Debt Securities;

(7) except as provided in the applicable Indenture, release the Subsidiary Guarantee of a Subsidiary Guarantor;

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(8) reduce the percentage in principal amount of Outstanding Debt Securities of any series, the consent of whose Holders is required for modification or amendment of the Indenture;

(9) reduce the percentage in principal amount of Outstanding Debt Securities of any series necessary for waiver of compliance with certain provisions of the Indenture or for waiver of certain defaults;

(10) modify such provisions with respect to modification, amendment or waiver; or

(11) following the making of an offer to purchase Debt Securities from any Holder that has been made pursuant to a covenant in such Indenture, modify such covenant in a manner adverse to such Holder.

The Holders of a majority in principal amount of the Outstanding Debt Securities of any series may waive compliance by us with certain restrictive provisions of the applicable Indenture. The Holders of a majority in principal amount of the Outstanding Debt Securities of any series may waive any past default under the applicable Indenture, except a default in the payment of principal, premium or interest and certain covenants and provisions of the Indenture which cannot be amended without the consent of the Holder of each Outstanding Debt Security of such series.

Each of the Indentures provides that in determining whether the Holders of the requisite principal amount of the Outstanding Debt Securities have given or taken any direction, notice, consent, waiver or other action under such Indenture as of any date:

(1) the principal amount of an Original Issue Discount Security that will be deemed to be Outstanding will be the amount of the principal that would be due and payable as of such date upon acceleration of maturity to such date;

(2) if, as of such date, the principal amount payable at the Stated Maturity of a Debt Security is not determinable (for example, because it is based on an index), the principal amount of such Debt Security deemed to be Outstanding as of such date will be an amount determined in the manner prescribed for such Debt Security;

(3) the principal amount of a Debt Security denominated in one or more foreign currencies or currency units that will be deemed to be Outstanding will be the United States-dollar equivalent, determined as of such date in the manner prescribed for such Debt Security, of the principal amount of such Debt Security (or, in the case of a Debt Security described in clause (1) or (2) above, of the amount described in such clause); and

(4) certain Debt Securities, including those owned by us, any Subsidiary Guarantor or any of our other Affiliates, will not be deemed to be Outstanding.

Except in certain limited circumstances, we will be entitled to set any day as a record date for the purpose of determining the Holders of Outstanding Debt Securities of any series entitled to give or take any direction, notice, consent, waiver or other action under the applicable Indenture, in the manner and subject to the limitations provided in the Indenture. In certain limited circumstances, the Trustee will be entitled to set a record date for action by Holders. If a record date is set for any action to be taken by Holders of a particular series, only persons who are Holders of Outstanding Debt Securities of that series on the record date may take such action. To be effective, such action must be taken by Holders of the requisite principal amount of such Debt Securities within a specified period following the record date. For any particular record date, this period will be 180 days or such other period as may be specified by us (or the Trustee, if it set the record date), and may be shortened or lengthened (but not beyond 180 days) from time to time.

Satisfaction and Discharge

Each Indenture will be discharged and will cease to be of further effect as to all outstanding Debt Securities of any series issued thereunder, when:

(1) either:

(a) all outstanding Debt Securities of that series that have been authenticated (except lost, stolen or destroyed Debt Securities that have been replaced or paid and Debt Securities for whose payment

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money has theretofore been deposited in trust and thereafter repaid to us) have been delivered to the Trustee for cancellation; or

(b) all outstanding Debt Securities of that series that have been not delivered to the Trustee for cancellation have become due and payable or will become due and payable at their Stated Maturity within one year or are to be called for redemption within one year under arrangements satisfactory to the Trustee and in any case we have irrevocably deposited with the Trustee as trust funds money in an amount sufficient, without consideration of any reinvestment of interest, to pay the entire indebtedness of such Debt Securities not delivered to the Trustee for cancellation, for principal, premium, if any, and accrued interest to the Stated Maturity or redemption date;

(2) we have paid or caused to be paid all other sums payable by us under the Indenture with respect to the Debt Securities of that series; and

(3) we have delivered an Officers’ Certificate and an Opinion of Counsel to the Trustee stating that all conditions precedent to satisfaction and discharge of the Indenture with respect to the Debt Securities of that series have been satisfied.

Legal Defeasance and Covenant Defeasance

To the extent indicated in the applicable prospectus supplement, we may elect, at our option at any time, to have our obligations discharged under provisions relating to defeasance and discharge of indebtedness, which we call “legal defeasance,” or relating to defeasance of certain restrictive covenants applied to the Debt Securities of any series, or to any specified part of a series, which we call “covenant defeasance.”

Legal Defeasance. The Indentures provide that, upon our exercise of our option (if any) to have the legal defeasance provisions applied to any series of Debt Securities, we and, if applicable, each Subsidiary Guarantor will be discharged from all our obligations, and, if such Debt Securities are Subordinated Debt Securities, the provisions of the Subordinated Indenture relating to subordination will cease to be effective, with respect to such Debt Securities (except for certain obligations to convert, exchange or register the transfer of Debt Securities, to replace stolen, lost or mutilated Debt Securities, to maintain paying agencies and to hold moneys for payment in trust) upon the deposit in trust for the benefit of the Holders of such Debt Securities of money or U.S. Government Obligations, or both, which, through the payment of principal and interest in respect thereof in accordance with their terms, will provide money in an amount sufficient (in the opinion of a nationally recognized firm of independent public accountants) to pay the principal of and any premium and interest on such Debt Securities on the respective Stated Maturities in accordance with the terms of the applicable Indenture and such Debt Securities. Such defeasance or discharge may occur only if, among other things:

(1) we have delivered to the applicable Trustee an Opinion of Counsel to the effect that we have received from, or there has been published by, the United States Internal Revenue Service a ruling, or there has been a change in tax law, in either case to the effect that Holders of such Debt Securities will not recognize gain or loss for federal income tax purposes as a result of such deposit and legal defeasance and will be subject to federal income tax on the same amount, in the same manner and at the same times as would have been the case if such deposit and legal defeasance were not to occur;

(2) no Event of Default or event that with the passing of time or the giving of notice, or both, shall constitute an Event of Default shall have occurred and be continuing at the time of such deposit or, with respect to any Event of Default described in clause (8) under “— Events of Default,” at any time until 121 days after such deposit;

(3) such deposit and legal defeasance will not result in a breach or violation of, or constitute a default under, any agreement or instrument (other than the applicable Indenture) to which we are a party or by which we are bound;

(4) in the case of Subordinated Debt Securities, at the time of such deposit, no default in the payment of all or a portion of principal of (or premium, if any) or interest on any Senior Debt shall have occurred and be

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continuing, no event of default shall have resulted in the acceleration of any Senior Debt and no other event of default with respect to any Senior Debt shall have occurred and be continuing permitting after notice or the lapse of time, or both, the acceleration thereof; and

(5) we have delivered to the Trustee an Opinion of Counsel to the effect that such deposit shall not cause the Trustee or the trust so created to be subject to the Investment Company Act of 1940.

Covenant Defeasance. The Indentures provide that, upon our exercise of our option (if any) to have the covenant defeasance provisions applied to any Debt Securities, we may fail to comply with certain restrictive covenants (but not with respect to conversion, if applicable), including those that may be described in the applicable prospectus supplement, and the occurrence of certain Events of Default, which are described above in clause (5) (with respect to such restrictive covenants) and clauses (6), (7) and (9) under “Events of Default” and any that may be described in the applicable prospectus supplement, will not be deemed to either be or result in an Event of Default and, if such Debt Securities are Subordinated Debt Securities, the provisions of the Subordinated Indenture relating to subordination will cease to be effective, in each case with respect to such Debt Securities. In order to exercise such option, we must deposit, in trust for the benefit of the Holders of such Debt Securities, money or U.S. Government Obligations, or both, which, through the payment of principal and interest in respect thereof in accordance with their terms, will provide money in an amount sufficient (in the opinion of a nationally recognized firm of independent public accountants) to pay the principal of and any premium and interest on such Debt Securities on the respective Stated Maturities in accordance with the terms of the applicable Indenture and such Debt Securities. Such covenant defeasance may occur only if we have delivered to the applicable Trustee an Opinion of Counsel to the effect that Holders of such Debt Securities will not recognize gain or loss for federal income tax purposes as a result of such deposit and covenant defeasance and will be subject to federal income tax on the same amount, in the same manner and at the same times as would have been the case if such deposit and covenant defeasance were not to occur, and the requirements set forth in clauses (2), (3), (4) and (5) above are satisfied. If we exercise this option with respect to any series of Debt Securities and such Debt Securities were declared due and payable because of the occurrence of any Event of Default, the amount of money and U.S. Government Obligations so deposited in trust would be sufficient to pay amounts due on such Debt Securities at the time of their respective Stated Maturities but may not be sufficient to pay amounts due on such Debt Securities upon any acceleration resulting from such Event of Default. In such case, we would remain liable for such payments.

If we exercise either our legal defeasance or covenant defeasance option, any Subsidiary Guarantee will terminate.

No Personal Liability of Directors, Officers, Employees and Stockholders

No director, officer, employee, incorporator, stockholder, member, partner or trustee of the Company or any Subsidiary Guarantor, as such, shall have any liability for any obligations of the Company or any Subsidiary Guarantor under the Debt Securities, the Indentures or any Subsidiary Guarantees or for any claim based on, in respect of, or by reason of, such obligations or their creation. By accepting a Debt Security, each Holder shall be deemed to have waived and released all such liability. The waiver and release shall be a part of the consideration for the issue of the Debt Securities. The waiver may not be effective to waive liabilities under the federal securities laws, and it is the view of the SEC that such a waiver is against public policy.

Notices

Notices to Holders of Debt Securities will be given by mail to the addresses of such Holders as they may appear in the Security Register.

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Title

We, the Subsidiary Guarantors, the Trustees and any agent of us, the Subsidiary Guarantors or a Trustee may treat the Person in whose name a Debt Security is registered as the absolute owner of the Debt Security (whether or not such Debt Security may be overdue) for the purpose of making payment and for all other purposes.

Governing Law

The Indentures and the Debt Securities will be governed by, and construed in accordance with, the law of the State of New York.

The Trustee

U.S. Bank National Association is, and any other Trustees chosen by us and appointed in a supplemental indenture for a particular series of Debt Securities will be, qualified to act under the Trust Indenture Act of 1939, as amended. We may maintain a banking relationship in the ordinary course of business with our Trustee and one or more of its affiliates.

Resignation or Removal of Trustee. If the Trustee has or acquires a conflicting interest within the meaning of the Trust Indenture Act, the Trustee must either eliminate its conflicting interest or resign, to the extent and in the manner provided by, and subject to the provisions of, the Trust Indenture Act and the applicable Indenture. Any resignation will require the appointment of a successor Trustee under the applicable Indenture in accordance with the terms and conditions of such Indenture.

The Trustee may resign or be removed by us with respect to one or more series of Debt Securities and a successor Trustee may be appointed to act with respect to any such series. The holders of a majority in aggregate principal amount of the Debt Securities of any series may remove the Trustee with respect to the Debt Securities of such series.

Limitations on Trustee if It Is Our Creditor. Each Indenture will contain certain limitations on the right of the Trustee, in the event that it becomes our creditor, to obtain payment of claims in certain cases, or to realize on certain property received in respect of any such claim as security or otherwise.

Certificates and Opinions to Be Furnished to Trustee. Each Indenture will provide that, in addition to other certificates or opinions that may be specifically required by other provisions of an Indenture, every application by us for action by the Trustee must be accompanied by an Officers’ Certificate and an Opinion of Counsel stating that, in the opinion of the signers, all conditions precedent to such action have been complied with by us.

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DESCRIPTION OF CAPITAL STOCK

The authorized capital stock of Oasis Petroleum Inc. consists of 300,000,000 shares of common stock, $0.01 par value per share, and 50,000,000 shares of preferred stock, $0.01 par value per share.

The following summary of the capital stock and amended and restated certificate of incorporation (the “Amended Charter”) and amended and restated bylaws (the “Amended Bylaws”) of Oasis Petroleum Inc. does not purport to be complete and is qualified in its entirety by reference to the provisions of applicable law and to our Amended Charter and Amended Bylaws, which are filed as exhibits to the registration statement of which this prospectus is a part.

Common Stock

As of June 30, 2014, we had 101,151,868 shares of common stock outstanding, all of which is voting common stock.

Except as provided by law or in a preferred stock designation, holders of common stock are entitled to one vote for each share held of record on all matters submitted to a vote of the stockholders, will have the exclusive right to vote for the election of directors and do not have cumulative voting rights. Except as otherwise required by law, holders of common stock, as such, are not entitled to vote on any amendment to the Amended Charter (including any certificate of designations relating to any series of preferred stock) that relates solely to the terms of any outstanding series of preferred stock if the holders of such affected series are entitled, either separately or together with the holders of one or more other such series, to vote thereon pursuant to the Amended Charter (including any certificate of designations relating to any series of preferred stock) or pursuant to the General Corporation Law of the State of Delaware. Subject to preferences that may be applicable to any outstanding shares or series of preferred stock, holders of common stock are entitled to receive ratably such dividends (payable in cash, stock or otherwise), if any, as may be declared from time to time by our board of directors out of funds legally available for dividend payments. All outstanding shares of common stock are fully paid and non-assessable, and any shares of common stock sold pursuant to this prospectus will be fully paid and non-assessable. The holders of common stock have no preferences or rights of conversion, exchange, pre-emption or other subscription rights. There are no redemption or sinking fund provisions applicable to the common stock. In the event of any liquidation, dissolution or winding-up of our affairs, holders of common stock will be entitled to share ratably in our assets that are remaining after payment or provision for payment of all of our debts and obligations and after liquidation payments to holders of outstanding shares of preferred stock, if any.

Preferred Stock

Our Amended Charter authorizes our board of directors, subject to any limitations prescribed by law, without further stockholder approval, to establish and to issue from time to time one or more classes or series of preferred stock, par value $0.01 per share, covering up to an aggregate of 50,000,000 shares of preferred stock. Each class or series of preferred stock will cover the number of shares and will have the powers, preferences, rights, qualifications, limitations and restrictions determined by the board of directors, which may include, among others, dividend rights, liquidation preferences, voting rights, conversion rights, preemptive rights and redemption rights. Except as provided by law or in a preferred stock designation, the holders of preferred stock will not be entitled to vote at or receive notice of any meeting of stockholders.

Anti-Takeover Effects of Provisions of Our Amended Charter, Our Amended Bylaws and Delaware Law

Some provisions of Delaware law, and our Amended Charter and our Amended Bylaws described below, contain provisions that could make the following transactions more difficult: acquisitions of us by means of a tender offer, a proxy contest or otherwise; or removal of our incumbent officers and directors. These provisions may also have the effect of preventing changes in our management. It is possible that these provisions could

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make it more difficult to accomplish or could deter transactions that stockholders may otherwise consider to be in their best interest or in our best interests, including transactions that might result in a premium over the market price for our shares.

These provisions, summarized below, are expected to discourage coercive takeover practices and inadequate takeover bids. These provisions are also designed to encourage persons seeking to acquire control of us to first negotiate with us. We believe that the benefits of increased protection and our potential ability to negotiate with the proponent of an unfriendly or unsolicited proposal to acquire or restructure us outweigh the disadvantages of discouraging these proposals because, among other things, negotiation of these proposals could result in an improvement of their terms.

Delaware Law

We are subject to the provisions of Section 203 of the Delaware General Corporation Law, or DGCL, regulating corporate takeovers. In general, those provisions prohibit a Delaware corporation, including those whose securities are listed for trading on the NYSE, from engaging in any business combination with any interested stockholder for a period of three years following the date that the stockholder became an interested stockholder, unless:

• the transaction is approved by the board of directors before the date the interested stockholder attained that status;

• upon consummation of the transaction that resulted in the stockholder becoming an interested stockholder, the interested stockholder owned at least 85% of the voting stock of the corporation outstanding at the time the transaction commenced; or

• on or after such time the business combination is approved by the board of directors and authorized at a meeting of stockholders by at least two-thirds of the outstanding voting stock that is not owned by the interested stockholder.

Section 203 defines “business combination” to include the following:

• any merger or consolidation involving the corporation and the interested stockholder;

• any sale, transfer, pledge or other disposition of 10% or more of the assets of the corporation involving the interested stockholder;

• subject to certain exceptions, any transaction that results in the issuance or transfer by the corporation of any stock of the corporation to the interested stockholder;

• any transaction involving the corporation that has the effect of increasing the proportionate share of the stock of any class or series of the corporation beneficially owned by the interested stockholder; or

• the receipt by the interested stockholder of the benefit of any loans, advances, guarantees, pledges or other financial benefits provided by or through the corporation.

In general, Section 203 defines an interested stockholder as any entity or person beneficially owning 15% or more of the outstanding voting stock of the corporation and any entity or person affiliated with or controlling or controlled by any of these entities or persons.

A Delaware corporation may “opt out” of Section 203 with an express provision in its original certificate of incorporation or an express provision in its certificate of incorporation or bylaws resulting from amendments approved by the holders of at least a majority of the corporation’s outstanding voting shares. We did not “opt out” of the provisions of Section 203. The statute could prohibit or delay mergers or other takeover or change in control attempts and, accordingly, may discourage attempts to acquire us.

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Amended Charter and Amended Bylaws

Among other things, our Amended Charter and Amended Bylaws:

• establish advance notice procedures with regard to stockholder proposals relating to the nomination of candidates for election as directors or new business to be brought before meetings of our stockholders. These procedures provide that notice of stockholder proposals must be timely given in writing to our corporate secretary prior to the meeting at which the action is to be taken. Generally, to be timely, notice must be received at our principal executive offices not less than 90 days nor more than 120 days prior to the first anniversary date of the annual meeting for the preceding year. Our Amended Bylaws specify the requirements as to form and content of all stockholders’ notices. These requirements may preclude stockholders from bringing matters before the stockholders at an annual or special meeting;

• provide our board of directors the ability to authorize undesignated preferred stock. This ability makes it possible for our board of directors to issue, without stockholder approval, preferred stock with voting or other rights or preferences that could impede the success of any attempt to change control of us. These and other provisions may have the effect of deferring hostile takeovers or delaying changes in control or management of our company;

• provide that the authorized number of directors may be changed only by resolution of the board of directors;

• provide that all vacancies, including newly created directorships, may, except as otherwise required by law, be filled by the affirmative vote of a majority of directors then in office, even if less than a quorum;

• provide that any action required or permitted to be taken by the stockholders must be effected at a duly called annual or special meeting of stockholders and may not be effected by any consent in writing in lieu of a meeting of such stockholders, subject to the rights of the holders of any series of preferred stock;

• provide that directors may be removed only for cause and only by the affirmative vote of holders of at least 80% of the voting power of our then outstanding common stock;

• provide our Amended Charter and Amended Bylaws may be amended by the affirmative vote of the holders of at least two-thirds of our then outstanding common stock;

• provide that special meetings of our stockholders may only be called by the board of directors, the chief executive officer or the chairman of the board;

• provide for our board of directors to be divided into three classes of directors, with each class as nearly equal in number as possible, serving staggered three year terms, other than directors which may be elected by holders of preferred stock, if any. This system of electing and removing directors may tend to discourage a third party from making a tender offer or otherwise attempting to obtain control of us, because it generally makes it more difficult for stockholders to replace a majority of the directors;

• provide that we renounce any interest in the business opportunities of EnCap Investments, L.P. or any private fund that it manages or advises or any of its officers, directors, agents, stockholders, members, partners, affiliates and subsidiaries (other than our directors who are presented business opportunities in their capacity as our director) and that they have no obligation to offer us those opportunities; and

• provide that our Amended Bylaws can be amended or repealed at any regular or special meeting of stockholders or by the board of directors.

Limitation of Liability and Indemnification Matters

Our Amended Charter limits the liability of our directors for monetary damages for breach of their fiduciary duty as directors, except for liability that cannot be eliminated under the DGCL. Delaware law provides that directors of a company will not be personally liable for monetary damages for breach of their fiduciary duty as directors, except for liabilities:

• for any breach of their duty of loyalty to us or our stockholders;

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• for acts or omissions not in good faith or which involve intentional misconduct or a knowing violation of law;

• for unlawful payment of dividend or unlawful stock repurchase or redemption, as provided under Section 174 of the DGCL; or

• for any transaction from which the director derived an improper personal benefit.

Any amendment, repeal or modification of these provisions will be prospective only and would not affect any limitation on liability of a director for acts or omissions that occurred prior to any such amendment, repeal or modification.

Our Amended Charter and Amended Bylaws also provide that we will indemnify our directors and officers to the fullest extent permitted by Delaware law. Our Amended Charter and Amended Bylaws also permit us to purchase insurance on behalf of any officer, director, employee or other agent for any liability arising out of that person’s actions as our officer, director, employee or agent, regardless of whether Delaware law would permit indemnification. We intend to enter into indemnification agreements with each of our current and future directors and officers. These agreements require us to indemnify these individuals to the fullest extent permitted under Delaware law against liability that may arise by reason of their service to us, and to advance expenses incurred as a result of any proceeding against them as to which they could be indemnified. We believe that the limitation of liability provision in our Amended Charter and the indemnification agreements will facilitate our ability to continue to attract and retain qualified individuals to serve as directors and officers.

Corporate Opportunity

Our Amended Charter provides that, to the fullest extent permitted by applicable law, we renounce any interest or expectancy in, or in being offered an opportunity to participate in, any business opportunity that may be from time to time presented to EnCap or its affiliates or any of their respective officers, directors, agents, shareholders, members, partners, affiliates and subsidiaries (other than us and our subsidiaries) or business opportunities that such parties participate in or desire to participate in, even if the opportunity is one that we might reasonably have pursued or had the ability or desire to pursue if granted the opportunity to do so, and no such person shall be liable to us for breach of any fiduciary or other duty, as a director or officer or controlling stockholder or otherwise, by reason of the fact that such person pursues or acquires any such business opportunity, directs any such business opportunity to another person or fails to present any such business opportunity, or information regarding any such business opportunity, to us unless, in the case of any such person who is our director or officer, any such business opportunity is expressly offered to such director or officer solely in his or her capacity as our director or officer.

Transfer Agent and Registrar

The transfer agent and registrar for our common stock is Computershare Trust Company, N.A.

Listing

Our common stock is listed on the NYSE under the symbol “OAS.”

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DESCRIPTION OF WARRANTS

We may issue warrants for the purchase of our common stock. Warrants may be issued independently or together with Debt Securities, preferred stock or common stock offered by any prospectus supplement and may be attached to or separate from any such offered securities. Each series of warrants will be issued under a separate warrant agreement to be entered into between us and a bank or trust company, as warrant agent, all as set forth in the prospectus supplement relating to the particular issue of warrants. The warrant agent will act solely as our agent in connection with the warrants and will not assume any obligation or relationship of agency or trust for or with any holders of warrants or beneficial owners of warrants. The following summary of certain provisions of the warrants does not purport to be complete and is subject to, and is qualified in its entirety by reference to, all provisions of the warrant agreements.

You should refer to the prospectus supplement relating to a particular issue of warrants for the terms of and information relating to the warrants, including, where applicable:

(1) the number of shares of common stock purchasable upon exercise of the warrants and the price at which such number of shares of common stock may be purchased upon exercise of the warrants;

(2) the date on which the right to exercise the warrants commences and the date on which such right expires (the “Expiration Date”);

(3) United States federal income tax consequences applicable to the warrants;

(4) the amount of the warrants outstanding as of the most recent practicable date; and

(5) any other terms of the warrants.

Warrants will be offered and exercisable for United States dollars only. Warrants will be issued in registered form only. Each warrant will entitle its holder to purchase such number of shares of common stock at such exercise price as is in each case set forth in, or calculable from, the prospectus supplement relating to the warrants. The exercise price may be subject to adjustment upon the occurrence of events described in such prospectus supplement. After the close of business on the Expiration Date (or such later date to which we may extend such Expiration Date), unexercised warrants will become void. The place or places where, and the manner in which, warrants may be exercised will be specified in the prospectus supplement relating to such warrants.

Prior to the exercise of any warrants, holders of the warrants will not have any of the rights of holders of common stock, including the right to receive payments of any dividends on the common stock purchasable upon exercise of the warrants, or to exercise any applicable right to vote.

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PLAN OF DISTRIBUTION

We may sell the offered securities in and outside the United States (1) through underwriters or dealers, (2) directly to purchasers, including our affiliates and stockholders, (3) through agents or (4) through a combination of any of these methods. The prospectus supplement will include the following information:

• the terms of the offering;

• the names of any underwriters or agents;

• the name or names of any managing underwriter or underwriters;

• the purchase price of the securities;

• the estimated net proceeds to us from the sale of the securities;

• any delayed delivery arrangements;

• any underwriting discounts, commissions and other items constituting underwriters’ compensation;

• any discounts or concessions allowed or reallowed or paid to dealers; and

• any commissions paid to agents.

Sale Through Underwriters or Dealers

If underwriters are used in the sale, the underwriters will acquire the securities for their own account for resale to the public, either on a firm commitment basis or a best efforts basis. The underwriters may resell the securities from time to time in one or more transactions, including negotiated transactions, at a fixed public offering price or at varying prices determined at the time of sale. Underwriters may offer securities to the public either through underwriting syndicates represented by one or more managing underwriters or directly by one or more firms acting as underwriters. Unless we inform you otherwise in the prospectus supplement, the obligations of the underwriters to purchase the securities will be subject to certain conditions. The underwriters may change from time to time any offering price and any discounts or concessions allowed or reallowed or paid to dealers.

During and after an offering through underwriters, the underwriters may purchase and sell the securities in the open market. These transactions may include overallotment and stabilizing transactions and purchases to cover syndicate short positions created in connection with the offering. The underwriters may also impose a penalty bid, which means that selling concessions allowed to syndicate members or other broker-dealers for the offered securities sold for their account may be reclaimed by the syndicate if the offered securities are repurchased by the syndicate in stabilizing or covering transactions. These activities may stabilize, maintain or otherwise affect the market price of the offered securities, which may be higher than the price that might otherwise prevail in the open market. If commenced, the underwriters may discontinue these activities at any time.

If dealers are used, we will sell the securities to them as principals. The dealers may then resell that securities to the public at varying prices determined by the dealers at the time of resale. We will include in the prospectus supplement the names of the dealers and the terms of the transaction.

Direct Sales and Sales Through Agents

We may sell the securities directly. In this case, no underwriters or agents would be involved. We may also sell the securities through agents designated from time to time. In the prospectus supplement, we will name any agent involved in the offer or sale of the offered securities, and we will describe any commissions payable to the agent.

Unless we inform you otherwise in the prospectus supplement, any agent will agree to use its reasonable best efforts to solicit purchases for the period of its appointment.

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We may sell the securities directly to institutional investors or others who may be deemed to be underwriters within the meaning of the Securities Act with respect to any sale of securities. We will describe the terms of any such sales in the prospectus supplement.

Remarketing Arrangements

Offered securities may also be offered and sold, if so indicated in the applicable prospectus supplement, in connection with a remarketing upon their purchase, in accordance with a redemption or repayment pursuant to their terms, or otherwise, by one or more remarketing firms, acting as principals for their own accounts or as agents for us. Any remarketing firm will be identified and the terms of its agreements, if any, with us and its compensation will be described in the applicable prospectus supplement. Remarketing firms may be deemed to be underwriters, as that term is defined in the Securities Act, in connection with the securities remarketed.

Delayed Delivery Contracts

If we so indicate in the prospectus supplement, we may authorize agents, underwriters or dealers to solicit offers from certain types of institutions to purchase securities from us at the public offering price under delayed delivery contracts. These contracts would provide for payment and delivery on a specified date in the future. The contracts would be subject only to those conditions described in the prospectus supplement. The prospectus supplement will describe the commission payable for solicitation of those contracts.

General Information

We may have agreements with the agents, dealers, underwriters and remarketing firms to indemnify them against certain civil liabilities, including liabilities under the Securities Act, or to contribute with respect to payments that the agents, dealers, underwriters or remarketing firms may be required to make. Agents, dealers, underwriters and remarketing firms may be customers of, engage in transactions with, or perform services for us in the ordinary course of their businesses.

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LEGAL MATTERS

Certain legal matters in connection with the securities will be passed upon by Vinson & Elkins L.L.P, Houston, Texas, as our counsel. Any underwriter or agent will be advised about other issues relating to any offering by its own legal counsel.

EXPERTS

The consolidated financial statements of Oasis Petroleum Inc. and subsidiaries and management’s assessment of the effectiveness of internal control over financial reporting (which is included in Management’s Report on Internal Control over Financial Reporting) incorporated in this prospectus by reference to the Annual Report on Form 10-K for the year ended December 31, 2013 have been so incorporated in reliance on the report of PricewaterhouseCoopers LLP, an independent registered public accounting firm, given on the authority of said firm as experts in auditing and accounting.

Certain estimates of our net crude oil and natural gas reserves and related information included or incorporated by reference in this prospectus have been derived from reports prepared by DeGolyer and MacNaughton. All such information has been so included or incorporated by reference on the authority of such firm as an expert in such matters.

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48,000,000 shares

Oasis Petroleum Inc.

Common stock

Preliminary prospectus supplement

Joint book-running managers

J.P. Morgan

Goldman, Sachs & Co.

Co-Managers

Wells Fargo Securities

Citigroup

Morgan Stanley

RBC Capital Markets

BB&T Capital Markets

BBVA

BOK Financial Securities, Inc

BTIG

Capital One Securities

CIBC Capital Markets

Citizens Capital Markets, Inc.

Comerica Securities

Credit Suisse

Deutsche Bank Securities

Evercore ISI

Heikkinen Energy Advisors

IBERIA Capital Partners L.L.C.

ING

Johnson Rice & Company L.L.C.

Tudor, Pickering, Holt & Co.

Regions Securities LLC

October 18, 2016