Exhibit 10.1

ULTRA PETROLEUM CORP.

6.125% Senior Notes due 2024

Purchase Agreement

September 4, 2014

Goldman, Sachs & Co.,

  As representative of the several Purchasers

  named in Schedule I hereto,

200 West Street,

New York, New York 10282-2198

Ladies and Gentlemen:

Ultra Petroleum Corp., a Yukon, Canada corporation (the “Company”), proposes, subject to the terms and conditions set forth in this agreement (this “Agreement”), to issue and sell to the Purchasers named in Schedule I hereto (the “Purchasers”) an aggregate of $850,000,000 principal amount of the 6.125% Senior Notes due 2024 specified above (the “Securities”).

Pursuant to a Purchase and Sale Agreement by and between SWEPI, LP (“SWEPI”) and Ultra Resources, Inc. and UPL Pinedale, LLC (together with Ultra Resources, Inc., the “PSA Subs”), dated as of August 13, 2014 (the “SWEPI PSA”), it is anticipated that the Company will purchase all of SWEPI’s assets in Sublette County, Wyoming (the “Target Assets”), in exchange for $925,000,000 and certain assets of the Company located in Pennsylvania (the “Divested Assets”). The Company intends to use a substantial portion of the net cash proceeds from the issuance of the Securities to finance the purchase of the Target Assets.

Contemporaneously with the closing of the issuance of the Securities, the Company, U.S. Bank National Association, as Trustee (the “Trustee”) and U.S. Bank National Association, as escrow agent (the “Escrow Agent”), will enter into an Escrow Agreement (the “Escrow Agreement”) pursuant to which at the Time of Delivery (defined herein) (i) the Purchasers will deposit with the Escrow Agent the net proceeds from the offering of the Securities and (ii) the Company will deposit with the Escrow Agent (or direct the deposit of) an amount of cash sufficient to pay the Special Mandatory Redemption Price (as defined in the Preliminary Offering Memorandum defined below), when and if due, including cash sufficient (as determined solely by the Company) to pay interest with respect to the Securities up to, but not including, November 18, 2014, in each case into an escrow account (the “Escrow Account”) for the benefit of the holders of the Securities.

1. The Company represents and warrants to, and agrees with, each of the Purchasers that:

(a) A preliminary offering memorandum, dated September 2, 2014 (the “Preliminary Offering Memorandum”) has been prepared in connection with the offering of the Securities, and an offering memorandum, dated September 4, 2014 (the “Offering Memorandum”), will be prepared in connection with the offering of the Securities. The Preliminary Offering Memorandum, as amended and supplemented immediately prior to the Applicable Time (as defined in Section 1(b)), is hereinafter referred to as the “Pricing Memorandum”. Any reference to the Preliminary Offering Memorandum, the Pricing Memorandum or the Offering Memorandum shall be deemed to refer to and include all documents filed with the United States Securities and Exchange Commission (the “Commission”) pursuant to Section 13(a), 13(c) or 15(d) of the United States Securities Exchange Act of 1934, as amended (the “Exchange Act”), on or prior to the date of such memorandum and incorporated by reference therein and any reference to the Preliminary Offering Memorandum or the Offering Memorandum, as the case may be, as amended or supplemented, as of any specified date, shall be deemed to include (i) any documents filed with the Commission pursuant to Section 13(a), 13(c) or 15(d) of the Exchange Act after the date of the Preliminary Offering Memorandum or the Offering Memorandum, as the case may be, and prior to such specified date and (ii) any Additional Issuer Information (as defined in Section 5(f)) furnished by the Company prior to the completion of the distribution of the Securities; and all documents filed under the Exchange Act and so deemed to be included in the Preliminary Offering Memorandum, the Pricing Memorandum or the Offering Memorandum, as the case may be, or any amendment or supplement thereto are hereinafter called the “Exchange Act Reports” (provided that where only sections of such documents are specifically incorporated by reference, only such sections shall be considered to be part of the “Exchange Act Reports”). The Exchange Act Reports, when they were or are filed with the Commission, conformed or will conform in all material respects to the applicable requirements of the Exchange Act and the applicable rules and regulations of the Commission thereunder; and no such documents were filed with the Commission since the Commission’s close of business on the business day immediately prior to the date of this Agreement and prior to the execution of this Agreement, except as set forth on Schedule II(a) hereof. The Preliminary Offering Memorandum or the Offering Memorandum and any amendments or supplements thereto and the Exchange Act Reports did not and will not, as of their respective dates, contain an untrue statement of a material fact or omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading; provided, however, that this representation and warranty shall not apply to any statements or omissions made in reliance upon and in conformity with information furnished in writing to the Company by a Purchaser through Goldman, Sachs & Co. expressly for use therein;

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(b) For the purposes of this Agreement, the “Applicable Time” is 12:05 p.m. (Eastern time) on the date of this Agreement. The Pricing Memorandum as supplemented by the information set forth in Schedule III hereto, taken together (collectively, the “Pricing Disclosure Package”) as of the Applicable Time, did not include any untrue statement of a material fact or omit to state any material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading; and each Company Supplemental Disclosure Document (as defined in Section 6(a)(i)) listed on Schedule II(b) hereto and each Permitted General Solicitation Material (as defined in Section 6(a)(i)) listed on Schedule II(d) hereto) does not conflict with the information contained in the Pricing Memorandum or the Offering Memorandum and each such Company Supplemental Disclosure Document and Permitted General Solicitation Material, as supplemented by and taken together with the Pricing Disclosure Package as of the Applicable Time, did not include any untrue statement of a material fact or omit to state any material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading; provided, however, that this representation and warranty shall not apply to statements or omissions made in a Company Supplemental Disclosure Document or Permitted General Solicitation Material in reliance upon and in conformity with information furnished in writing to the Company by a Purchaser through Goldman, Sachs & Co. expressly for use therein;

(c) Neither the Company nor any of its subsidiaries has sustained since the date of the latest audited financial statements included in the Pricing Disclosure Package any material loss or interference with its business from fire, explosion, flood or other calamity, whether or not covered by insurance, or from any labor dispute or court or governmental action, order or decree, otherwise than as set forth or contemplated in the Pricing Disclosure Package; and, since the respective dates as of which information is given in the Pricing Disclosure Package, there has not been any change in the capital stock, membership interests or long-term debt of the Company or any of its subsidiaries or any material adverse change, or any development involving a prospective material adverse change, in or affecting the general affairs, management, financial position, shareholders’ equity (or members’ interests) or results of operations of the Company and its subsidiaries, taken as a whole (a “Material Adverse Effect”), otherwise than as set forth or contemplated in the Pricing Disclosure Package;

(d) The Company and each of its subsidiaries has been duly incorporated or formed and is validly existing as a corporation or limited liability company in good standing under the laws of its respective jurisdiction of incorporation or formation, with power and authority

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(corporate, limited liability company and other) to own its properties and conduct its business as described in the Pricing Disclosure Package and the Offering Memorandum, and, except to the extent the failure to be so qualified or be in good standing would not, individually or in the aggregate, have a Material Adverse Effect, has been duly qualified as a foreign corporation or limited liability company for the transaction of business and is in good standing under the laws of each other jurisdiction in which it owns or leases properties or conducts any business so as to require such qualification, or is subject to no material liability or disability by reason of the failure to be so qualified or be in good standing in any such jurisdiction;

(e) The Company has an authorized capitalization as set forth in the Pricing Disclosure Package and the Offering Memorandum, and all of the issued shares of capital stock of the Company have been duly and validly authorized and issued and are fully paid and non-assessable; and all of the issued shares of capital stock, membership interests or other equity interests, as applicable, of each subsidiary of the Company have been duly and validly authorized and issued, are fully paid and non-assessable and are owned directly or indirectly by the Company, free and clear of all liens, encumbrances, equities or claims;

(f) The financial statements (including the related notes thereto) of the Company and its consolidated subsidiaries included or incorporated by reference in each of the Pricing Disclosure Package and the Offering Memorandum comply in all material respects with the applicable requirements of the Securities Act of 1933, as amended (the “Act”) and the Exchange Act, as applicable, and present fairly the financial position of the Company and its consolidated subsidiaries as of the dates indicated and the results of their operations and the changes in their cash flows for the periods specified; such financial statements have been prepared in conformity with the generally accepted accounting principles in the United States applied on a consistent basis throughout the periods covered thereby, and any supporting schedules included or incorporated by reference in each of the Pricing Disclosure Package and the Offering Memorandum present fairly the information required to be stated therein; and the other financial information included or incorporated by reference in each of the Pricing Disclosure Package and the Offering Memorandum has been derived from the accounting records of the Company and its consolidated subsidiaries and presents fairly the information shown thereby. The interactive data in eXtensbile Business Reporting Language included or incorporated by reference in the Offering Memorandum and the Pricing Disclosure Package fairly presents the information called for in all material respects and is prepared in all material respects in accordance with the Commission’s rules and guidelines applicable thereto.

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(g) The Securities have been duly authorized by the Company and, when duly executed, authenticated, issued and delivered as provided in the Indenture and paid for as provided in this Agreement, will be duly and validly issued and outstanding and will constitute valid and legally binding obligations of the Company, enforceable against the Company and will be entitled to the benefits of and be in the form contemplated by that certain indenture to be dated as of September 18, 2014 (the “Indenture”) between the Company and the Trustee, under which they are to be issued, which will be substantially in the form previously delivered to you; the Indenture has been duly authorized by the Company and, when executed and delivered by the Company and the Trustee, the Indenture will constitute a valid and legally binding instrument, enforceable against the Company in accordance with its terms, subject, as to enforcement, to bankruptcy, insolvency, reorganization and other laws of general applicability relating to or affecting creditors’ rights and to general equity principles and entitled to the benefits provided by the Indenture; and the Securities and the Indenture will conform in all material respects to the descriptions thereof in the Pricing Disclosure Package and the Offering Memorandum and will be in substantially the form previously delivered to you;

(h) The Company has all requisite corporate power to execute, deliver and perform its obligations under this Agreement. This Agreement has been duly and validly authorized, executed and delivered by the Company.

(i) The Escrow Agreement has been duly authorized, and as of the Time of Delivery (as defined herein), will have been duly executed and delivered by the Company, and will constitute a valid and legally binding instrument, enforceable against the Company in accordance with its terms, subject, as to enforcement, to bankruptcy, insolvency, reorganization and other laws of general applicability relating to or affecting creditors’ rights and to general equity principles and except that rights to indemnity and contribution thereunder may be limited by applicable law and public policy; and the Escrow Agreement will conform in all material respects to the descriptions thereof in the Pricing Disclosure Package and the Offering Memorandum.

(j) The Registration Rights Agreement to be dated as of the Time of Delivery (the “Registration Rights Agreement”), which will be substantially in the form previously delivered to you, has been duly authorized, and as of the Time of Delivery (as defined herein), will have been duly executed and delivered by the Company, and will constitute a valid and legally binding instrument, enforceable against the Company in accordance with its terms, subject, as to enforcement, to bankruptcy, insolvency, reorganization and other laws of general applicability relating to or affecting creditors’ rights and to general equity principles and except that rights to indemnity and contribution thereunder may be limited by applicable law and public policy; and the Registration Rights Agreement will conform in all material respects to the descriptions thereof in the Pricing Disclosure Package and the Offering Memorandum;

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(k) The senior notes due 2024 to be offered in exchange for the Securities pursuant to the Registration Rights Agreement (the “Exchange Securities”) have been duly authorized by the Company and if and when issued and authenticated in accordance with the terms of the Indenture and delivered in accordance with the exchange offer provided for in the Registration Rights Agreement (the “Exchange Offer”), will be validly issued and delivered and will constitute valid and binding obligations of the Company entitled to the benefits of the Indenture, enforceable against the Company in accordance with their terms, subject, as to enforcement, to bankruptcy, insolvency, reorganization and other laws of general applicability relating to or affecting creditors’ rights and to general equity principles, and will be entitled to the benefits provided by the Indenture;

(l) None of the transactions contemplated by this Agreement (including, without limitation, the use of the proceeds from the sale of the Securities) will violate or result in a violation of Section 7 of the Exchange Act, or any regulation promulgated thereunder, including, without limitation, Regulations T, U, and X of the Board of Governors of the Federal Reserve System;

(m) Prior to the date hereof, neither the Company nor any of its affiliates has taken any action which is designed to or which has constituted or which might have been expected to cause or result in stabilization or manipulation of the price of any security of the Company in connection with the offering of the Securities;

(n) The issue and sale of the Securities and the compliance by the Company with all of the provisions of the Securities, the Indenture, the Registration Rights Agreement, the Escrow Agreement, the Exchange Securities and this Agreement and the consummation of the transactions herein and therein contemplated and the application of the proceeds from the sale of the Securities as described under “Use of Proceeds” in the Pricing Disclosure Package and the Offering Memorandum will not conflict with or result in a breach or violation of (i) any of the terms or provisions of, or constitute a default under, any indenture, mortgage, deed of trust, loan agreement or other agreement or instrument to which the Company or any of its subsidiaries is a party or by which the Company or any of its subsidiaries is bound or to which any of the property or assets of the Company or any of its subsidiaries is subject, (ii) the provisions of the Articles of Incorporation, as amended, or By-laws of the Company or (iii) any statute or any order, rule or regulation of any court or governmental agency or body having jurisdiction over the Company or any of its subsidiaries or any of their properties, except for, with respect to clauses (i) and (iii), any for any such conflict, breach, or violation which would not, individually or in the aggregate, have a Material Adverse Effect;

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(o) No consent, approval, authorization, order, registration or qualification of or with any such court or governmental agency or body is required for the issue and sale of the Securities or the consummation by the Company of the transactions contemplated by this Agreement, the Securities, the Exchange Securities, the Registration Rights Agreement, the Escrow Agreement or the Indenture, except for such consents, approvals, authorizations, registrations or qualifications as may be required (i) under state securities or Blue Sky laws in connection with the purchase and distribution of the Securities by the Purchasers or (ii) with respect to the Exchange Securities, under the Act, the Trust Indenture Act and applicable state securities or Blue Sky laws as contemplated by the Registration Rights Agreement;

(p) Neither the Company nor any of its subsidiaries is (i) in violation of its Articles of Incorporation, as amended, or By-laws or equivalent organizational document or (ii) in default in the performance or observance of any material obligation, covenant or condition contained in any indenture, mortgage, deed of trust, loan agreement, lease or other agreement or instrument to which it is a party or by which it or any of its properties may be bound, except for, with respect to clause (ii), any such violation or default which would not, individually or in the aggregate, have a Material Adverse Effect;

(q) The statements set forth in the Pricing Disclosure Package and the Offering Memorandum under the caption “Description of Notes”, insofar as they purport to constitute a summary of the terms of the Securities, under the caption “Description of Certain Indebtedness,” insofar as they purport to constitute a summary of the terms of the documents referred to therein, and under the caption “Certain United States Federal Income Tax Considerations,” insofar as they purport to describe the provisions of the laws and documents referred to therein, are accurate, complete and fair;

(r) The statements set forth in the Pricing Disclosure Package and the Offering Memorandum under the caption “Certain Canadian Federal Income Tax Considerations,” insofar as they purport to describe the provisions of the laws referred to therein as they apply to investors described therein, are accurate, complete and fair;

(s) Other than as set forth in the Pricing Disclosure Package and the Offering Memorandum, there are no legal or governmental proceedings pending to which the Company or any of its subsidiaries is a party or of which any property of the Company or any of its subsidiaries is the subject which, if determined adversely to the Company or any of its subsidiaries, would, individually or in the aggregate, have a Material Adverse Effect or materially affect the ability to consummate the transactions contemplated hereby; and, to the best of the Company’s knowledge, no such proceedings are threatened or contemplated by governmental authorities or threatened by others;

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(t) When the Securities are issued and delivered pursuant to this Agreement, the Securities will not be of the same class (within the meaning of Rule 144A under the Act) as securities which are listed on a national securities exchange registered under Section 6 of the Exchange Act or quoted in a U.S. automated inter-dealer quotation system;

(u) The Company is subject to Section 13 or 15(d) of the Exchange Act and is a reporting issuer in each of British Columbia, Alberta, Saskatchewan, Manitoba, Ontario, Quebec, Nova Scotia and the Yukon, and is not noted in default of any of its public company reporting obligations;

(v) The Company and its subsidiaries are not, and after giving effect to the offering and sale of the Securities and the application of the proceeds thereof, will not be, an “investment company”, as such term is defined in the United States Investment Company Act of 1940, as amended (the “Investment Company Act”);

(w) Neither the Company nor any person acting on its or their behalf (other than the Purchasers, as to which no representation is made) has offered or sold the Securities by means of any general solicitation or general advertising within the meaning of Rule 502(c) under the Act (other than by means of a Permitted General Solicitation, as defined below) or, with respect to Securities sold outside the United States to non-U.S. persons (as defined in Rule 902 under the Act), by means of any directed selling efforts within the meaning of Rule 902 under the Act and the Company, any affiliate of the Company and any person acting on its or their behalf has complied with and will implement the “offering restriction” within the meaning of such Rule 902;

(x) Within the preceding six months, except for the issuance of the Securities pursuant to this Agreement, neither the Company nor any other person acting on behalf of the Company has offered or sold to any person any Securities, or any securities of the same or a similar class as the Securities, other than Securities offered or sold to the Purchasers hereunder. The Company will take reasonable precautions designed to insure that any offer or sale, direct or indirect, in the United States or to any U.S. person (as defined in Rule 902 under the Act) of any Securities or any substantially similar security issued by the Company, within six months subsequent to the date on which the distribution of the Securities has been completed (as notified to the Company by Goldman, Sachs & Co.), is made under restrictions and other circumstances reasonably designed not to affect the status of the offer and sale of the Securities in the United States and to U.S. persons contemplated by this Agreement as transactions exempt from the registration provisions of the Act;

(y) The Company maintains a system of “internal control over financial reporting” (as such term is defined in Rule 13a-15(f) of the Exchange Act) that complies with the requirements of the Exchange Act and has been designed by the Company’s principal executive officer and principal financial officer, or under their supervision, to provide

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reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles and the interactive data in eXtensbile Business Reporting Language incorporated by reference in the Offering Memorandum and the Pricing Disclosure Package is prepared in all material respects in accordance with the Commission’s rules and guidelines applicable thereto. The Company is not aware of any material weaknesses in its internal control over financial reporting;

(z) Since the date of the latest audited financial statements included or incorporated by reference in the Pricing Disclosure Package, there has been no change in the Company’s internal control over financial reporting that has materially affected, or is reasonably likely to materially affect, the Company’s internal control over financial reporting;

(aa) The Company maintains a system of “disclosure controls and procedures” (as such term is defined in Rule 13a-15(e) of the Exchange Act) that is designed to ensure that information required to be disclosed by the Company in reports that it files or submits under the Exchange Act is recorded, processed, summarized and reported within time periods that comply with the requirements of the Exchange Act; such disclosure controls and procedures have been designed to ensure that material information relating to the Company and its subsidiaries is made known to the Company’s principal executive officer and principal financial officer by others within those entities; and such disclosure controls and procedures are effective;

(bb) Ernst & Young, LLP, which has audited certain financial statements of the Company and its subsidiaries is an independent registered public accounting firm under the rules and regulations adopted by the Commission and the Public Company Accounting Oversight Board (United States) as required by the Act;

(cc) EKS&H LLLP, which has audited the statement of revenues and direct operating expenses of Axia Energy, LLC oil and gas properties purchased by the Company for the year December 31, 2012, included in the Company’s Current Report on Form 8-K/A filed with the Securities and Exchange Commission on February 24, 2014 is an independent registered public accounting firm under the rules and regulations adopted by the Commission and the Public Company Accounting Oversight Board (United States) as required by the Act;

(dd) Netherland Sewell & Associates, Inc., an oil and gas consulting firm (“NSAI”), whose summary letter from its report as of December 31, 2013 appears in the Pricing Disclosure Package or is incorporated by reference therein, whose reserve estimates from its reports are included or are incorporated by reference therein and who has delivered the letter referred to in Section 8(g) hereof, was, as of the date of such reports, and is, as of the date hereof, an independent petroleum engineer with respect to the Company. The Company is

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not aware of any facts or circumstances that would in the aggregate result in a material adverse change in the aggregate net proved reserves, or the aggregate present value or the standardized measure of the future net cash flows from the written engineering reports prepared by NSAI dated February 1, 2012, February 11, 2013 and January 27, 2014; the information furnished by the Company to NSAI for purposes of preparing its reports, including, without limitation, production, costs of operation and development, current prices for production, agreements relating to current and future operations and sales of production, was true, correct and complete in all material respects on the dates supplied and, as of the dates of the applicable engineering reports of NSAI, was prepared in accordance with customary industry practices. The pro forma and roll-forward estimates of the net proved reserves and related data of the Company as of June 30, 2014 contained in the Pricing Disclosure Package reflect adjustments to the Company’s estimates of reserves as of December 31, 2013 and were calculated in all material respects in accordance with the methodology described in the Pricing Disclosure Package. The Company is not aware of any facts or circumstances that would in the aggregate result in a material adverse change in the aggregate net proved reserves, or the aggregate present value or the standardized measure of the future net cash flows from its pro forma and roll-forward estimates of net proved reserves as of June 30, 2014 contained in the Pricing Disclosure Package;

(ee) Except as described in the Pricing Disclosure Package, the Company and its subsidiaries have defensible title to all of their interests in oil and gas properties and all other real property owned by the Company and its subsidiaries and good title to all other properties owned by them, in each case, free and clear of all mortgages, pledges, liens, security interests, claims, restrictions or encumbrances of any kind except such as (i) are described in the Pricing Disclosure Package, (ii) liens and encumbrances under operating agreements, unitization and pooling agreements, production sales contracts, farm-out agreements and other oil and gas exploration participation and production agreements, in each case that secure payment of amounts not yet due and payable for the performance of other unmatured obligations and are of a scope and nature customary in the oil and gas industry or arise in connection with drilling and production operations, or (iii) could not, in the aggregate, reasonably be expected to have a Material Adverse Effect. Except as could not, in the aggregate, reasonably be expected to have a Material Adverse Effect or as described in the Pricing Disclosure Package, all of the leases and subleases of real property of the Company or any of its subsidiaries and under which the Company or any of its subsidiaries holds properties described in the Pricing Disclosure Package, are in full force and effect, and, except as could not, in the aggregate, reasonably be expected to have a Material Adverse Effect or as described in the Pricing Disclosure Package, neither the Company nor any of its subsidiaries has received written notice of any claim of any sort

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that has been asserted by anyone adverse to the rights of the Company or any of its subsidiaries under any of such leases or subleases, or affecting or questioning the rights of the Company or such subsidiary to the continued possession of the leased or subleased premises under any such lease or sublease. With respect to interests in oil and gas leases obtained by or on behalf of the Company or its subsidiaries that have not yet been drilled or included in a unit for drilling, the Company or its subsidiaries have carried out such title investigations in accordance with the practices customary in the oil and gas industry in the areas in which the leased properties are located;

(ff) The Company and each of its subsidiaries carry, or are covered by, insurance from insurers of recognized financial responsibility in such amounts and covering such risks as is adequate for the conduct of their respective businesses and the value of their respective properties. All policies of insurance of the Company and its subsidiaries are in full force and effect; the Company and its subsidiaries are in compliance with the terms of such policies in all material respects; and neither the Company nor any of its subsidiaries has received notice from any insurer or agent of such insurer that capital improvements or other expenditures are required or necessary to be made in order to continue such insurance; there are no claims by the Company or any of its subsidiaries under any such policy or instrument as to which any insurance company is denying liability or defending under a reservation of rights clause; and neither the Company nor any such subsidiary has any reason to believe that it will not be able to renew its existing insurance coverage as and when such coverage expires or to obtain similar coverage from similar insurers as may be necessary to continue its business at a cost that could not reasonably be expected to have a Material Adverse Effect;

(gg) The statistical and market-related data included or incorporated by reference in the Pricing Disclosure Package and the consolidated financial statements of the Company and its subsidiaries included or incorporated by reference in the Pricing Disclosure Package are based on or derived from sources that the Company believes to be reliable and accurate in all material respects;

(hh) No subsidiary of the Company is currently prohibited, directly or indirectly, from paying any dividends to the Company, from making any other distribution on such subsidiary’s capital stock, from repaying to the Company any loans or advances to such subsidiary from the Company or from transferring any of such subsidiary’s property or assets to the Company or any other subsidiary of the Company, except as described in the Pricing Disclosure Package under the caption “Description of Notes—Limitation on Restrictions on Distributions from Restricted Subsidiaries”;

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(ii) As of the date hereof, (i) all royalties, rentals, deposits and other amounts owed under the oil and gas leases constituting the oil and gas properties of the Company and its subsidiaries have been properly and timely paid (other than amounts held in suspense accounts pending routine payments or related to disputes about the proper identification of royalty owners and except where the failure to timely pay or pay such amounts could not, individually or in the aggregate, have a Material Adverse Effect); and no material amount of proceeds from the sale or production attributable to the oil and gas properties of the Company and its subsidiaries are currently being held in suspense by any purchaser thereof, except where such amounts due could not, individually or in the aggregate, have a Material Adverse Effect, and (ii) there are no claims under take-or-pay contracts pursuant to which natural gas purchasers have any make-up rights affecting the interests of the Company or its subsidiaries in their oil and gas properties, except where such claims could not, individually or in the aggregate, have a Material Adverse Effect;

(jj) Except as described in the Pricing Disclosure Package and except such matters as would not, singly or in the aggregate, result in a Material Adverse Effect: (i) neither the Company nor any of its subsidiaries is in violation of any federal, state, local or foreign statute, law, rule, regulation, ordinance, code, policy or rule of common law or any judicial or administrative interpretation thereof, including any judicial or administrative order, consent, decree or judgment, relating to pollution or protection of the environment (including, without limitation, ambient air, surface water, groundwater, land surface or subsurface strata) or wildlife, including, without limitation, laws and regulations relating to the release or threatened release of chemicals, pollutants, contaminants, wastes, toxic substances, hazardous substances, petroleum or petroleum products or asbestos containing materials (collectively, “Hazardous Materials”) or to the manufacture, processing, distribution, use, treatment, storage, disposal, transport or handling of Hazardous Materials (collectively, “Environmental Laws”); (ii) the Company and its subsidiaries have all permits, authorizations and approvals required under applicable Environmental Laws for their operations as presently conducted and are each in compliance with their requirements; (iii) there are no pending or threatened administrative, regulatory or judicial actions, suits, written demands, claims, liens, notices of noncompliance or violation, investigation or proceedings arising pursuant to any Environmental Law asserted against the Company or any of its subsidiaries and (iv) to the knowledge of the Company, there are no events or circumstances that would reasonably be expected to form the basis of an order for clean-up or remediation, or an action, suit or proceeding by any private party or governmental body or agency, against or affecting the Company or any of its subsidiaries relating to Hazardous Materials or Environmental Laws or the violation of any Environmental Laws;

(kk) (i) Each employee benefit plan, within the meaning of Section 3(3) of the Employee Retirement Income Security Act of 1974, as amended (“ERISA”), for which the Company or any member of its “Controlled Group” (defined as any organization which is a member of a controlled group of corporations within the meaning of Section 414 of the Internal

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Revenue Code of 1986, as amended (the “Code”)) would have any liability (each, a “Plan”) has been maintained in compliance with its terms and the requirements of any applicable statutes, orders, rules and regulations, including but not limited to ERISA and the Code; (ii) no prohibited transaction, within the meaning of Section 406 of ERISA or Section 4975 of the Code, has occurred with respect to any Plan excluding transactions effected pursuant to a statutory or administrative exemption; (iii) for each Plan that is subject to the funding rules of Section 412 of the Code or Section 302 of ERISA, no Plan has failed (whether or not waived), or is reasonably expected to fail, to satisfy the minimum funding standards (within the meaning of Section 302 of ERISA or Section 412 of the Code) applicable to such Plan; (iv) no Plan is, or is reasonably expected to be, in “at risk status” (within the meaning of Section 303(i) of ERISA) or “endangered status” or “critical status” (within the meaning of Section 305 of ERISA); (v) the fair market value of the assets of each Plan exceeds the present value of all benefits accrued under such Plan (determined based on those assumptions used to fund such Plan); (vi) no “reportable event” (within the meaning of Section 4043(c) of ERISA) has occurred or is reasonably expected to occur; (vii) each Plan that is intended to be qualified under Section 401(a) of the Code is so qualified and nothing has occurred, whether by action or by failure to act, which would cause the loss of such qualification and (viii) neither the Company nor any member of the Controlled Group has incurred, nor reasonably expects to incur, any liability under Title IV of ERISA (other than contributions to the Plan or premiums to the PBGC, in the ordinary course and without default) in respect of a Plan (including a “multiemployer plan”, within the meaning of Section 4001(a)(3) of ERISA), except in each case with respect to the events or conditions set forth in (i) through (viii) hereof, as would not, individually or in the aggregate, have a Material Adverse Effect;

(ll) The Company is not a “passive foreign investment company” (“PFIC”) within the meaning of Section 1297 of the United States Internal Revenue Code of 1986, as amended, for any taxable year ended on or before December 31, 2012, is not a PFIC, and does not expect to become a PFIC in its current taxable year or any subsequent taxable year;

(mm) None of the Company, any of its subsidiaries nor, to the knowledge of the Company, any director, officer, agent, employee, affiliate or other person associated with or acting on behalf of the Company or any of its subsidiaries has (i) used any corporate funds for any unlawful contribution, gift, entertainment or other unlawful expense relating to political activity; (ii) made or taken an act in furtherance of any offer, promise or authorization of any direct or indirect unlawful payment or benefit to any foreign or domestic government or regulatory official or employee, including of any government-owned or controlled entity or of a public international organization, or any person acting in an official capacity for or on behalf of any of the foregoing, or any political party or party official or candidate for political office from corporate funds; (iii) violated or is in violation of any provision of the Foreign

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Corrupt Practices Act of 1977, as amended, or any applicable law or regulation implementing the OECD Convention on Combating Bribery of Foreign Public Officials in International Business Transactions; (iv) violated or is in violation of any provision of the Bribery Act 2010 of the United Kingdom, or any other applicable anti-bribery or anti-corruption laws; or (v) made, offered, agreed, requested or taken an act in furtherance of any unlawful bribe or other unlawful benefit, including without limitation, any rebate, payoff, influence payment, kickback or other unlawful payment or improper benefit. The Company and its subsidiaries have instituted, maintain and enforce, and will continue to maintain and enforce, policies and procedures designed to promote and ensure compliance with all applicable anti-bribery and anti-corruption laws;

(nn) The operations of the Company and its subsidiaries are and have been conducted at all times in compliance with applicable financial recordkeeping and reporting requirements of the Currency and Foreign Transactions Reporting Act of 1970, as amended, the money laundering statutes of all jurisdictions, the rules and regulations thereunder and any related or similar rules, regulations or guidelines, issued, administered or enforced by any governmental agency having jurisdiction over the Company or any of its subsidiaries (collectively, the “Money Laundering Laws”) and no action, suit or proceeding by or before any court or governmental agency, authority or body or any arbitrator involving the Company or any of its subsidiaries with respect to the Money Laundering Laws is pending or, to the knowledge of the Company, threatened;

(oo) None of the Company, any of its subsidiaries or, to the knowledge of the Company, any director, officer, agent, employee or affiliate of the Company or any of its subsidiaries is currently the subject or the target of any sanctions administered or enforced by the U.S. Government, including, without limitation, the Office of Foreign Assets Control of the U.S. Department of the Treasury (“OFAC”), the U.S. Department of State, or the U.S. Department of State, the United Nations Security Council (“UNSC”), the European Union, Her Majesty’s Treasury (“HMT”) or other relevant sanctions authority (collectively, “Sanctions”), nor is the Company, any of its subsidiaries located, organized or resident in a country or territory that is the subject or the target of Sanctions, including, without limitation, Cuba, Iran, North Korea, Sudan and Syria (each, a “Sanctioned Country”) and the Company will not directly or indirectly use the proceeds of the offering of the Securities hereunder, or lend, contribute or otherwise make available such proceeds to any subsidiary, joint venture partner or other person or entity (i) to fund or facilitate any activities of or business with any person, that, at the time of such funding or facilitation, is the subject of Sanctions, (ii) to fund or facilitate any activities of or business in any Sanctioned Country or (iii) in any other manner that will result in a violation by any person (including any person participating in the transaction, whether as Purchaser, advisor, investor or otherwise) of Sanctions. For the past 5 years, the Company and its subsidiaries

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have not knowingly engaged in and are not now knowingly engaged in any dealings or transactions with any person that at the time of the dealing or transaction is or was the subject or the target of Sanctions or with any Sanctioned Country.

(pp) The SWEPI PSA, has been duly authorized, executed and delivered by the PSA Subs, constitutes a valid and binding agreement of the PSA Subs and, to the knowledge of the Company, of the other party thereto, enforceable against the PSA Subs in accordance with its terms, subject, as to enforcement, to bankruptcy, insolvency, reorganization and other laws of general applicability relating to or affecting creditors’ rights and to general equity principles and except that rights to indemnity and contribution thereunder may be limited by applicable law and public policy and, as of the date hereof, the PSA Subs have all necessary power and authority to perform its obligations thereunder.

(qq) The Company is exempt from the oil and gas reserve and resource reporting requirements, and all other requirements, of National Instrument 51-101 Standards of Disclosure of Oil and Gas Activities of the Canadian Securities Administrators in each province and territory of Canada where it would otherwise be subject to those requirements by virtue of exemption orders issued by the Canadian securities regulators (the “Exemptive Relief”). The Company is currently in compliance with all of the conditions of the Exemptive Relief, including the requirement that not more than 10% of the Company’s common shares be held by persons resident in Canada, and the requirement that not more than 10% of the Company’s common shareholders be residents of Canada;

(rr) The Company’s head office is not located within Yukon. The Company’s executive officers and directors are not resident in Yukon. The business of the Company and its subsidiaries is not administered from, and the operations of the Company and its subsidiaries are not conducted in, Yukon. No acts, advertisements, solicitations, conduct or negotiations by the Company or its affiliates in furtherance of the offering and sale of the Securities contemplated hereby have taken place in Yukon (including any underwriting or investor relations activities), it being understood that no representation or warranty is made with respect to the activities of the Purchasers. The offer and sale of the Securities to any purchaser outside Yukon, and that is not resident in Yukon, is not subject to the prospectus requirements of the Securities Act (Yukon);

(ss) The Company has applied for an exemption from the requirements of Part 7 of the Business Corporations Act (Yukon) that would otherwise apply to the Company and the Indenture in connection with the offering, issue, sale and delivery of the Securities by the Company to the Purchasers, the distribution of the Securities by the Purchasers as contemplated by this Agreement and the issue and delivery of the Exchange Securities pursuant to the Exchange Offer; and

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(tt) There shall exist at and as of the Applicable Time and Time of Delivery, no condition that would constitute a material breach (or an event that with notice or lapse of time, or both, would constitute such a material breach) under the SWEPI PSA. Neither of the PSA Subs has received or sent any notification of breach of representations and warranties under Section 7.2 of the SWEPI PSA. There are no conditions to closing remaining unsatisfied under the SWEPI PSA of the PSA Subs, as Purchaser (as defined in the SWEPI PSA) or as Seller (as defined in the SWEPI PSA) other than (i) the passage of the appropriate waiting periods under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended and (ii) the delivery of all closing documents and purchase consideration.

2. Subject to the terms and conditions herein set forth, the Company agrees to issue and sell to each of the Purchasers, and each of the Purchasers agrees, severally and not jointly, to purchase from the Company, at a purchase price of 98.64643% of the principal amount thereof, plus accrued interest, if any, from September 18, 2014 to the Time of Delivery hereunder, the principal amount of Securities set forth opposite the name of such Purchaser in Schedule I hereto. The net proceeds to be deposited by the Purchasers in the Escrow Account at the Time of Delivery in accordance with the Escrow Agreement is $838,494,655.

3. Upon the authorization by you of the release of the Securities, the several Purchasers propose to offer the Securities for sale upon the terms and conditions set forth in this Agreement and the Offering Memorandum and each Purchaser, acting severally and not jointly, hereby represents and warrants to, and agrees with the Company that:

(a) It will sell the Securities only to: (i) persons who it reasonably believes are “qualified institutional buyers” (“QIBs”) within the meaning of Rule 144A under the Act in transactions meeting the requirements of Rule 144A or, (ii) upon the terms and conditions set forth in Annex I to this Agreement;

(b) It is an Institutional Accredited Investor (within the meaning of Rule 501 under the Act); and

(c) It and each of its affiliates will not solicit offers to purchase or sell the Securities in any province or territory of Canada except on a private placement basis in accordance with the Offering Memorandum (including for the purposes hereof, any Canadian offering document appended thereto) and in compliance with Canadian Securities Laws to “accredited investors” as such term is used in National Instrument 45-106 – Prospectus and Registration Exemptions (“NI 45-106”) resident in each of the provinces of Ontario, Quebec, Alberta, British Columbia or Manitoba (collectively, the “Provinces”) through a registrant properly registered or otherwise so as to not require the filing of a prospectus or any other document with respect to the distribution of the Securities under applicable Canadian Securities Laws (other than, if required by applicable Canadian Securities Laws,

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the filing of the Offering Memorandum (including for the purposes hereof, any Canadian offering document appended thereto) provided to purchasers in the Provinces and Form 45-106F1 pursuant to NI 45-106 or any equivalent form in any of the Provinces) and to provide such information as may reasonably be required by the Company in respect of the purchasers of the Securities in order for the Company to fulfill its filing obligations under applicable Canadian Securities Laws, if any. “Canadian Securities Laws” means the securities acts or similar statutes of each of the Provinces and the Yukon and all regulations, rules, policy statements, instruments, notices and blanket orders or rulings thereunder.

4.       (a) The Securities to be purchased by each Purchaser hereunder will be represented by one or more definitive global Securities in book-entry form which will be deposited by or on behalf of the Company with The Depository Trust Company (“DTC”) or its designated custodian. The Company will deliver the Securities to Goldman, Sachs & Co., for the account of each Purchaser, against payment by or on behalf of such Purchaser of the purchase price therefor by wire transfer in Federal (same day) funds, by causing DTC to credit the Securities to the account of Goldman, Sachs & Co. at DTC. The Company will cause the certificates representing the Securities to be made available to Goldman, Sachs & Co. for checking at least twenty-four hours prior to the Time of Delivery (as defined below) at the office of Haynes and Boone, LLP, 1221 McKinney Street, Suite 2100, Houston, Texas 77010 (the “Closing Location”). The time and date of such delivery and payment shall be 9:30 a.m., New York City time, on September 18, 2014 or such other time and date as Goldman, Sachs & Co. and the Company may agree upon in writing. Such time and date are herein called the “Time of Delivery”.

(b) The documents to be delivered at the Time of Delivery by or on behalf of the parties hereto pursuant to Section 8 hereof, including the cross-receipt for the Securities and any additional documents requested by the Purchasers pursuant to Section 8 hereof, will be delivered at such time and date at the Closing Location, and the Securities will be delivered at the office of DTC (or its designated custodian), all at the Time of Delivery. A meeting will be held at the Closing Location at 4:00 p.m., New York City time, on the New York Business Day next preceding the Time of Delivery, at which meeting the final drafts of the documents to be delivered pursuant to the preceding sentence will be available for review by the parties hereto. For the purposes of this Section 4, “New York Business Day” shall mean each Monday, Tuesday, Wednesday, Thursday and Friday which is not a day on which banking institutions in New York are generally authorized or obligated by law or executive order to close.

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5. The Company agrees with each of the Purchasers:

(a) To prepare the Offering Memorandum which will consist of the Preliminary Offering Memorandum updated for the information set forth on Schedule III or otherwise reasonably acceptable to you; to make no amendment or any supplement to the Offering Memorandum which shall be disapproved by you, acting reasonably, promptly after reasonable notice thereof; and to furnish you with copies thereof;

(b) Promptly from time to time to take such action as you may reasonably request to qualify the Securities for offering and sale under the securities laws of such jurisdictions as you may request and to comply with such laws so as to permit the continuance of sales and dealings therein in such jurisdictions for as long as may be necessary to complete the distribution of the Securities, provided that in connection therewith the Company shall not be required to qualify as a foreign corporation or to file a general consent to service of process in any jurisdiction;

(c) If at any time prior to the Time of Delivery (i) any event shall occur or condition shall exist as a result of which any of the Pricing Disclosure Package as then amended or supplemented would include any untrue statement of a material fact or omit to state any material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading or (ii) it is necessary to amend or supplement any of the Pricing Disclosure Package to comply with law, the Company will immediately notify the Purchasers thereof and forthwith prepare and, subject to paragraph (b) above, furnish to the Purchasers such amendments or supplements to any of the Pricing Disclosure Package (or any document to be filed with the Commission and incorporated by reference therein) as may be necessary so that the statements in any of the Pricing Disclosure Package as so amended or supplemented (including such documents to be incorporated by reference therein) will not, in light of the circumstances under which they were made, be misleading or so that any of the Pricing Disclosure Package will comply with law.

(d) To furnish the Purchasers with written and electronic copies of the Offering Memorandum and any amendment or supplement thereto in such quantities as you may from time to time reasonably request, and if, at any time prior to the expiration of nine months after the date of the Offering Memorandum, any event shall have occurred as a result of which the Offering Memorandum as then amended or supplemented would include an untrue statement of a material fact or omit to state any material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made when such Offering Memorandum is delivered, not misleading, or, if for any other reason it shall be necessary or desirable during such same period to amend or supplement the Offering Memorandum, to notify you and upon your request to prepare and furnish without charge to each Purchaser and to any dealer in securities as many written and electronic copies as

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you may from time to time reasonably request of an amended Offering Memorandum or a supplement to the Offering Memorandum which will correct such statement or omission or effect such compliance;

(e) During the period beginning from the date hereof and continuing until the date that is 90 days after the Time of Delivery, not to offer, issue, sell, contract to sell, pledge, grant any option to purchase, make any short sale or otherwise transfer or dispose of, directly or indirectly, or file with the Commission a registration statement under the Act relating to any securities of the Company that are substantially similar to the Securities, other than the Exchange Securities, or publicly disclose the intention to make any offer, sale, pledge, disposition or filing without your prior written consent;

(f) Not to be or become, at any time prior to the expiration of two years after the Time of Delivery, an open-end investment company, unit investment trust, closed-end investment company or face-amount certificate company that is or is required to be registered under Section 8 of the Investment Company Act;

(g) At any time when the Company is not subject to Section 13 or 15(d) of the Exchange Act, for the benefit of holders from time to time of Securities, to furnish at its expense, upon request, to holders of Securities and prospective purchasers of Securities information (the “Additional Issuer Information”) satisfying the requirements of subsection (d)(4)(i) of Rule 144A under the Act;

(h) Except for such documents that are publicly available on EDGAR, to furnish to the holders of the Securities as soon as practicable after the end of each fiscal year an annual report (including a balance sheet and statements of income, stockholders’ equity and cash flows of the Company and its consolidated subsidiaries certified by independent public accountants) and, as soon as practicable after the end of each of the first three quarters of each fiscal year (beginning with the fiscal quarter ending after the date of the Offering Memorandum), to make available to its stockholders consolidated summary financial information of the Company and its subsidiaries for such quarter in reasonable detail;

(i) During the period of one year after the Time of Delivery, the Company will not, and will not permit any of its “affiliates” (as defined in Rule 144 under the Act) to, resell any of the Securities which constitute “restricted securities” under Rule 144 that have been reacquired by any of them (other than pursuant to a registration statement that has been declared effective under the Act); and

(j) To use the net proceeds received by the Company from the sale of the Securities pursuant to this Agreement in the manner specified in the Pricing Disclosure Package under the caption “Use of Proceeds”.

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6.       (a) (i) The Company represents and agrees that, without the prior consent of Goldman, Sachs & Co., it and its affiliates and any other person acting on its or their behalf (other than the Purchasers, as to which no statement is given) (x) have not made and will not make any offer relating to the Securities that, if the offering of the Securities contemplated by this Agreement were conducted as a public offering pursuant to a registration statement filed under the Act with the Commission, would constitute an “issuer free writing prospectus,” as defined in Rule 433 under the Act (any such offer is hereinafter referred to as a “Company Supplemental Disclosure Document”) and (y) have not solicited and will not solicit offers for, and have not offered or sold and will not offer or sell, the Securities by means of any form of general solicitation or general advertising within the meaning of Rule 502(c) of Regulation D other than any such solicitation listed on Schedule II(d) (each such solicitation, a “Permitted General Solicitation”; each written general solicitation document listed on Schedule II(d), a “Permitted General Solicitation Material”);   (ii) each Purchaser, severally and not jointly, represents and agrees that, without the prior consent of the Company and Goldman, Sachs & Co., other than one or more term sheets or other communications relating to the Securities containing customary information and conveyed to purchasers of securities or any Permitted General Solicitation Material, it has not made and will not make any offer relating to the Securities that, if the offering of the Securities contemplated by this Agreement were conducted as a public offering pursuant to a registration statement filed under the Act with the Commission, would constitute a “free writing prospectus,” as defined in Rule 405 under the Act (any such offer (other than any such term sheets, communications and any Permitted General Solicitation Material), is hereinafter referred to as a “Purchaser Supplemental Disclosure Document”); and   (iii) any Company Supplemental Disclosure Document, Purchaser Supplemental Disclosure Document or Permitted General Solicitation Material, the use of which has been consented to by the Company and Goldman, Sachs & Co., is listed as applicable on Schedule II(b), Schedule II(c) or Schedule II(d) hereto, respectively;

7. The Company covenants and agrees with the several Purchasers that the Company will pay or cause to be paid the following: (i) the fees, disbursements and expenses of the Company’s counsel and accountants in connection with the issue of the Securities and all other expenses in connection with the preparation, printing, reproduction and filing of the Preliminary Offering Memorandum and the Offering Memorandum and any amendments and supplements thereto and the mailing and delivering of copies thereof to the Purchasers and dealers; (ii) the cost of printing or producing any Agreement among Purchasers, this Agreement, the Indenture, the Securities, the Registration Rights Agreement, the Blue Sky Memorandum, closing documents (including any compilations thereof), Permitted General Solicitation Materials and any other documents in connection with the offering, purchase, sale and delivery of the Securities; (iii) all expenses in

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connection with the qualification of the Securities for offering and sale under state securities laws as provided in Section 5(b) hereof, including the fees and disbursements of counsel for the Purchasers in connection with such qualification and in connection with the Blue Sky and legal investment surveys; (iv) any fees charged by securities rating services for rating the Securities; (v) the cost of preparing the Securities; (vi) the fees and expenses of the Trustee and any agent of the Trustee and the fees and disbursements of counsel for the Trustee in connection with the Indenture and the Securities; (vii) all costs and expenses incurred in connection with any “road show” presentation to potential purchasers of the Securities; and (viii) all other costs and expenses incident to the performance of its obligations hereunder which are not otherwise specifically provided for in this Section. It is understood, however, that, except as provided in this Section, and Sections 9 and 12 hereof, the Purchasers will pay all of their own costs and expenses, including the fees of their counsel and transfer taxes on resale of any of the Securities by them.

8. The obligations of the Purchasers hereunder shall be subject, in their discretion, to the condition that all representations and warranties and other statements of the Company herein are, at and as of the date hereof and the Time of Delivery, true and correct, the condition that the Company shall have performed all of its obligations hereunder theretofore to be performed, and the following additional conditions:

(a) Vinson & Elkins L.L.P., counsel for the Purchasers, shall have furnished to you such opinion or opinions, dated the Time of Delivery, in form and substance satisfactory to you, with respect to such matters as you may reasonably request, and such counsel shall have received such papers and information as they may reasonably request to enable them to pass upon such matters;

(b) Haynes and Boone, LLP, counsel for the Company, shall have furnished to you their written opinion, dated the Time of Delivery, in form and substance satisfactory to you, and substantially as set forth on Annex II(a) hereto;

(c) Garrett Smith, Principal Counsel for the Company, will deliver the opinions in Annex II(b).

(d) Lackowicz & Hoffman, Yukon counsel for the Company, shall have furnished to you their written opinion, dated the Time of Delivery, in form and substance satisfactory to you, and substantially as set forth on Annex II(c) hereto;

(e) Bennett Jones, Canadian counsel for the Company, shall have furnished to you their written opinion, dated the Time of Delivery, in form and substance satisfactory to you, and substantially as set forth on Annex II(d) hereto;

(f) On the date of the Offering Memorandum concurrently with the execution of this Agreement and also at the Time of Delivery, Ernst & Young, LLP shall have furnished to you a letter or letters, dated the respective dates of delivery thereof, in form and substance satisfactory to you;

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(g) On the date of the Offering Memorandum concurrently with the execution of this Agreement and also at the Time of Delivery, EKS&H LLLP shall have furnished to you a letter or letters, dated the respective dates of delivery thereof, in form and substance satisfactory to you;

(h) On the date of the Offering Memorandum concurrently with the execution of this Agreement and also at the Time of Delivery, Netherland, Sewell & Associates, Inc. shall have furnished to you a letter or letters, dated the respective dates of delivery thereof, in form and substance satisfactory to you;

(i) (i) Neither the Company nor any of its subsidiaries shall have sustained since the date of the latest audited financial statements included in the Pricing Disclosure Package any loss or interference with its business from fire, explosion, flood or other calamity, whether or not covered by insurance, or from any labor dispute or court or governmental action, order or decree, otherwise than as set forth or contemplated in the Pricing Disclosure Package, and

(ii) since the respective dates as of which information is given in the Pricing Disclosure Package there shall not have been any change in the capital stock or long-term debt of the Company or any of its subsidiaries or any change, or any development involving a prospective change, in or affecting the general affairs, management, financial position, stockholders’ equity or results of operations of the Company and its subsidiaries, otherwise than as set forth or contemplated in the Pricing Disclosure Package, the effect of which, in any such case described in clause (i) or (ii), is in your judgment so material and adverse as to make it impracticable or inadvisable to proceed with the offering or the delivery of the Securities on the terms and in the manner contemplated in this Agreement and in each of the Pricing Disclosure Package and the Offering Memorandum;

(j) On or after the Applicable Time (i) no downgrading shall have occurred in the rating accorded the Company’s debt securities by any “nationally recognized statistical rating organization”, as that term is defined by the Commission for purposes of Section 3(a)(62) of the Exchange Act, and (ii) no such organization shall have publicly announced that it has under surveillance or review, with possible negative implications, its rating of any of the Company’s debt securities;

(k) On or after the Applicable Time there shall not have occurred any of the following: (i) a suspension or material limitation in trading in securities generally on the New York Stock Exchange; (ii) a suspension or material limitation in trading in the Company’s securities on the New York Stock Exchange; (iii) a general moratorium on commercial banking activities declared by either Federal or New York or Texas State authorities or a material disruption

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in commercial banking or securities settlement or clearance services in the United States; (iv) the outbreak or escalation of hostilities involving the United States or the declaration by the United States of a national emergency or war or (v) the occurrence of any other calamity or crisis or any change in financial, political or economic conditions in the United States or elsewhere, if the effect of any such event specified in clause (iv) or (v) in your judgment makes it impracticable or inadvisable to proceed with the offering or the delivery of the Securities on the terms and in the manner contemplated in the Pricing Disclosure Package and the Offering Memorandum;

(l) The Purchasers shall have received an executed copy of the Indenture;

(m) The Company, the Trustee and the Escrow Agent shall have on or prior to the Time of Delivery executed and delivered the Escrow Agreement, and the Purchasers shall have received a copy thereof, duly executed by the Company, the Trustee and the Escrow Agent, and all funds shall have been paid into the Escrow Account created under the Escrow Agreement, or arrangements shall have been made to pay such amounts into escrow, which shall include the net proceeds from the offering of the Securities plus such additional amounts required to be paid by the Company in an aggregate amount sufficient to pay the Special Mandatory Redemption Price;

(n) The Securities shall be eligible for clearance and settlement through the facilities of DTC;

(o) The Purchasers shall have received a counterpart of the Registration Rights Agreement that shall have been executed and delivered by a duly authorized officer of the Company; and

(p) The Company shall have furnished or caused to be furnished to you at the Time of Delivery certificates of officers of the Company satisfactory to you as to the accuracy of the representations and warranties of the Company herein at and as of such Time of Delivery, as to the performance by the Company of all of its obligations hereunder to be performed at or prior to such Time of Delivery, as to the matters set forth in subsection (h) of this Section and as to such other matters as you may reasonably request.

9.

(a) The Company will indemnify and hold harmless each Purchaser against any losses, claims, damages or liabilities, joint or several, to which such Purchaser may become subject, under the Act or otherwise, insofar as such losses, claims, damages or liabilities (or actions in respect thereof) arise out of or are based upon an untrue statement or alleged untrue statement of a material fact contained in any Preliminary Offering Memorandum, the Pricing Memorandum, the Pricing Disclosure Package, the Offering Memorandum, or any amendment or supplement thereto, any Company Supplemental Disclosure Document, any Permitted General Solicitation Material or arise out of or are

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based upon the omission or alleged omission to state therein a material fact necessary to make the statements therein not misleading, and will reimburse each Purchaser for any legal or other expenses reasonably incurred by such Purchaser in connection with investigating or defending any such action or claim as such expenses are incurred; provided, however, that the Company shall not be liable in any such case to the extent that any such loss, claim, damage or liability arises out of or is based upon an untrue statement or alleged untrue statement or omission or alleged omission made in any Preliminary Offering Memorandum, the Pricing Memorandum, the Pricing Disclosure Package, the Offering Memorandum or any such amendment or supplement, any Company Supplemental Disclosure Document or any Permitted General Solicitation Material, in reliance upon and in conformity with written information furnished to the Company by any Purchaser through Goldman, Sachs & Co. expressly for use therein.

(b) Each Purchaser, severally and not jointly, will indemnify and hold harmless the Company against any losses, claims, damages or liabilities to which the Company may become subject, under the Act or otherwise, insofar as such losses, claims, damages or liabilities (or actions in respect thereof) arise out of or are based upon an untrue statement or alleged untrue statement of a material fact contained in any Preliminary Offering Memorandum, the Pricing Memorandum, the Pricing Disclosure Package, the Offering Memorandum, or any amendment or supplement thereto, or any Company Supplemental Disclosure Document, any Permitted General Solicitation Material or arise out of or are based upon the omission or alleged omission to state therein a material fact or necessary to make the statements therein not misleading, in each case to the extent, but only to the extent, that such untrue statement or alleged untrue statement or omission or alleged omission was made in any Preliminary Offering Memorandum, the Pricing Memorandum, the Pricing Disclosure Package, the Offering Memorandum or any such amendment or supplement, any Company Supplemental Disclosure Document or any Permitted General Solicitation Material, in reliance upon and in conformity with written information furnished to the Company by such Purchaser through Goldman, Sachs & Co. expressly for use therein; and each Purchaser will reimburse the Company for any legal or other expenses reasonably incurred by the Company in connection with investigating or defending any such action or claim as such expenses are incurred.

(c) Promptly after receipt by an indemnified party under subsection (a) or (b) above of notice of the commencement of any action, such indemnified party shall, if a claim in respect thereof is to be made against the indemnifying party under such subsection, notify the indemnifying party in writing of the commencement thereof; but the omission so to notify the indemnifying party shall not relieve it from any liability which it may have to any indemnified party otherwise than under such subsection. In case any such action shall be brought against any indemnified party and it shall notify the indemnifying party of the

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commencement thereof, the indemnifying party shall be entitled to participate therein and, to the extent that it shall wish, jointly with any other indemnifying party similarly notified, to assume the defense thereof, with counsel satisfactory to such indemnified party (who shall not, except with the consent of the indemnified party, be counsel to the indemnifying party), and, after notice from the indemnifying party to such indemnified party of its election so to assume the defense thereof, the indemnifying party shall not be liable to such indemnified party under such subsection for any legal expenses of other counsel or any other expenses, in each case subsequently incurred by such indemnified party, in connection with the defense thereof other than reasonable costs of investigation. In any such proceeding, any indemnified party shall have the right to retain its own counsel, but the fees and expenses of such counsel shall be at the expense of such indemnified party unless (i) the indemnifying party and the indemnified party shall have mutually agreed to the contrary; (ii) the indemnifying party has failed within a reasonable time to retain counsel reasonably satisfactory to the indemnified party; (iii) the indemnified party shall have reasonably concluded that there may be legal defenses available to it that are different from or in addition to those available to the indemnifying party; or (iv) the named parties in any such proceeding (including any impleaded parties) include both the indemnifying party and the indemnified party and representation of both parties by the same counsel would be inappropriate due to actual or potential differing interests between them. No indemnifying party shall, without the written consent of the indemnified party, effect the settlement or compromise of, or consent to the entry of any judgment with respect to, any pending or threatened action or claim in respect of which indemnification or contribution may be sought hereunder (whether or not the indemnified party is an actual or potential party to such action or claim) unless such settlement, compromise or judgment (i) includes an unconditional release of the indemnified party from all liability arising out of such action or claim and (ii) does not include a statement as to, or an admission of, fault, culpability or a failure to act, by or on behalf of any indemnified party.

(d) If the indemnification provided for in this Section 9 is unavailable to or insufficient to hold harmless an indemnified party under subsection (a) or (b) above in respect of any losses, claims, damages or liabilities (or actions in respect thereof) referred to therein, then each indemnifying party shall contribute to the amount paid or payable by such indemnified party as a result of such losses, claims, damages or liabilities (or actions in respect thereof) in such proportion as is appropriate to reflect the relative benefits received by the Company on the one hand and the Purchasers on the other from the offering of the Securities. If, however, the allocation provided by the immediately preceding sentence is not permitted by applicable law or if the indemnified party failed to give the notice required under subsection (c) above, then each indemnifying party shall contribute to such amount paid or payable by such indemnified party in such proportion as is appropriate to reflect not only

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such relative benefits but also the relative fault of the Company on the one hand and the Purchasers on the other in connection with the statements or omissions which resulted in such losses, claims, damages or liabilities (or actions in respect thereof), as well as any other relevant equitable considerations. The relative benefits received by the Company on the one hand and the Purchasers on the other shall be deemed to be in the same proportion as the total net proceeds from the offering (before deducting expenses) received by the Company bear to the total discounts and commissions received by the Purchasers, in each case as set forth in the Offering Memorandum. The relative fault shall be determined by reference to, among other things, whether the untrue or alleged untrue statement of a material fact or the omission or alleged omission to state a material fact relates to information supplied by the Company on the one hand or the Purchasers on the other and the parties’ relative intent, knowledge, access to information and opportunity to correct or prevent such statement or omission. The Company and the Purchasers agree that it would not be just and equitable if contribution pursuant to this subsection (d) were determined by pro rata allocation (even if the Purchasers were treated as one entity for such purpose) or by any other method of allocation which does not take account of the equitable considerations referred to above in this subsection (d). The amount paid or payable by an indemnified party as a result of the losses, claims, damages or liabilities (or actions in respect thereof) referred to above in this subsection (d) shall be deemed to include any legal or other expenses reasonably incurred by such indemnified party in connection with investigating or defending any such action or claim. Notwithstanding the provisions of this subsection (d), no Purchaser shall be required to contribute any amount in excess of the amount by which the total price at which the Securities purchased by it and distributed to investors were offered to investors exceeds the amount of any damages which such Purchaser has otherwise been required to pay by reason of such untrue or alleged untrue statement or omission or alleged omission. The Purchasers’ obligations in this subsection (d) to contribute are several in proportion to their respective purchase obligations and not joint.

(e) The obligations of the Company under this Section 9 shall be in addition to any liability which the Company may otherwise have and shall extend, upon the same terms and conditions, to any affiliate, director or officer of each Purchaser and each person, if any, who controls any Purchaser within the meaning of the Act; and the obligations of the Purchasers under this Section 9 shall be in addition to any liability which the respective Purchasers may otherwise have and shall extend, upon the same terms and conditions, to each officer and director of the Company and to each person, if any, who controls the Company within the meaning of the Act.

10.       (a) If any Purchaser shall default in its obligation to purchase the Securities which it has agreed to purchase hereunder, you may in your discretion arrange for you or another party

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or other parties to purchase such Securities on the terms contained herein. If within thirty-six hours after such default by any Purchaser you do not arrange for the purchase of such Securities, then the Company shall be entitled to a further period of thirty-six hours within which to procure another party or other parties satisfactory to you to purchase such Securities on such terms. In the event that, within the respective prescribed periods, you notify the Company that you have so arranged for the purchase of such Securities, or the Company notifies you that it has so arranged for the purchase of such Securities, you or the Company shall have the right to postpone the Time of Delivery for a period of not more than seven days, in order to effect whatever changes may thereby be made necessary in the Offering Memorandum, or in any other documents or arrangements, and the Company agrees to prepare promptly any amendments or supplements to the Offering Memorandum which in your opinion may thereby be made necessary. The term “Purchaser” as used in this Agreement shall include any person substituted under this Section with like effect as if such person had originally been a party to this Agreement with respect to such Securities.

(b) If, after giving effect to any arrangements for the purchase of the Securities of a defaulting Purchaser or Purchasers by you and the Company as provided in subsection (a) above, the aggregate principal amount of such Securities which remains unpurchased does not exceed one-eleventh of the aggregate principal amount of all the Securities, then the Company shall have the right to require each non-defaulting Purchaser to purchase the principal amount of Securities which such Purchaser agreed to purchase hereunder and, in addition, to require each non-defaulting Purchaser to purchase its pro rata share (based on the principal amount of Securities which such Purchaser agreed to purchase hereunder) of the Securities of such defaulting Purchaser or Purchasers for which such arrangements have not been made; but nothing herein shall relieve a defaulting Purchaser from liability for its default.

If, after giving effect to any arrangements for the purchase of the Securities of a defaulting Purchaser or Purchasers by you and the Company as provided in subsection (a) above, the aggregate principal amount of Securities which remains unpurchased exceeds one-eleventh of the aggregate principal amount of all the Securities, or if the Company shall not exercise the right described in subsection (b) above to require non-defaulting Purchasers to purchase Securities of a defaulting Purchaser or Purchasers, then this Agreement shall thereupon terminate, without liability on the part of any non-defaulting Purchaser or the Company, except for the expenses to be borne by the Company and the Purchasers as provided in Section 6 hereof and the indemnity and contribution agreements in Section 9 hereof; but nothing herein shall relieve a defaulting Purchaser from liability for its default.

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11. The respective indemnities, agreements, representations, warranties and other statements of the Company and the several Purchasers, as set forth in this Agreement or made by or on behalf of them, respectively, pursuant to this Agreement, shall remain in full force and effect, regardless of any investigation (or any statement as to the results thereof) made by or on behalf of any Purchaser or any affiliate, director, officer or controlling person of any Purchaser, or the Company, or any officer or director or controlling person of the Company, and shall survive delivery of and payment for the Securities.

12. If this Agreement shall be terminated pursuant to Section 10 hereof, the Company shall not then be under any liability to any Purchaser except as provided in Sections 7 and 9 hereof; but, if for any other reason, the Securities are not delivered by or on behalf of the Company as provided herein, the Company will reimburse the Purchasers through you for all expenses approved in writing by you, including fees and disbursements of counsel, reasonably incurred by the Purchasers in making preparations for the purchase, sale and delivery of the Securities, but the Company shall then be under no further liability to any Purchaser except as provided in Sections 7 and 9 hereof.

13. In all dealings hereunder, you shall act on behalf of each of the Purchasers, and the parties hereto shall be entitled to act and rely upon any statement, request, notice or agreement on behalf of any Purchaser made or given by you.

All statements, requests, notices and agreements hereunder shall be in writing, and if to the Purchasers shall be delivered or sent by mail or facsimile transmission to you as the representative at 200 West Street, New York, New York 10282-2198, Attention: Registration Department; and if to the Company shall be delivered or sent by mail or facsimile transmission to the address of the Company set forth in the Offering Memorandum, Attention: Corporate Secretary; provided, however, that any notice to a Purchaser pursuant to Section 9 hereof shall be delivered or sent by mail or facsimile transmission to such Purchaser at its address set forth in its Purchasers’ Questionnaire, which address will be supplied to the Company by you upon request. Any such statements, requests, notices or agreements shall take effect upon receipt thereof.

In accordance with the requirements of the USA Patriot Act (Title III of Pub. L. 107-56 (signed into law October 26, 2001)), the Purchasers are required to obtain, verify and record information that identifies their respective clients, including the Company, which information may include the name and address of their respective clients, as well as other information that will allow the Purchasers to properly identify their respective clients.

14. This Agreement shall be binding upon, and inure solely to the benefit of, the Purchasers, the Company and, to the extent provided in Sections 9 and 11 hereof, the officers and directors of the Company and each person who controls the Company or any Purchaser, and their respective heirs, executors, administrators, successors and assigns, and no other person shall acquire or have any right under or by virtue of this Agreement. No purchaser of any of the Securities from any Purchaser shall be deemed a successor or assign by reason merely of such purchase.

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15. Time shall be of the essence of this Agreement.

16. The Company acknowledges and agrees that (i) the purchase and sale of the Securities pursuant to this Agreement is an arm’s-length commercial transaction between the Company, on the one hand, and the several Purchasers, on the other, (ii) in connection therewith and with the process leading to such transaction each Purchaser is acting solely as a principal and not the agent or fiduciary of the Company, (iii) no Purchaser has assumed an advisory or fiduciary responsibility in favor of the Company with respect to the offering contemplated hereby or the process leading thereto (irrespective of whether such Purchaser has advised or is currently advising the Company on other matters) or any other obligation to the Company except the obligations expressly set forth in this Agreement and (iv) the Company has consulted its own legal and financial advisors to the extent it deemed appropriate. The Company agrees that it will not claim that the Purchaser, or any of them, has rendered advisory services of any nature or respect, or owes a fiduciary or similar duty to the Company, in connection with such transaction or the process leading thereto.

17. This Agreement supersedes all prior agreements and understandings (whether written or oral) between the Company and the Purchasers, or any of them, with respect to the subject matter hereof.

18. THIS AGREEMENT AND ANY MATTERS RELATED TO THIS TRANSACTION SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK WITHOUT REGARD TO PRINCIPLES OF CONFLICT OF LAWS THAT WOULD RESULT IN THE APPLICATION OF ANY LAW OTHER THAN THE LAWS OF THE STATE OF NEW YORK. The Company agrees that any suit or proceeding arising in respect of this agreement or our engagement will be tried exclusively in the U.S. District Court for the Southern District of New York or, if that court does not have subject matter jurisdiction, in any state court located in The City and County of New York and the Company agrees to submit to the jurisdiction of, and to venue in, such courts.

19. The Company and each of the Purchasers hereby irrevocably waives, to the fullest extent permitted by applicable law, any and all right to trial by jury in any legal proceeding arising out of or relating to this Agreement or the transactions contemplated hereby.

20. This Agreement may be executed by any one or more of the parties hereto in any number of counterparts, each of which shall be deemed to be an original, but all such respective counterparts shall together constitute one and the same instrument.

21. Notwithstanding anything herein to the contrary, the Company (and the Company’s employees, representatives, and other agents) are authorized to disclose to any and all persons, the tax treatment and tax structure of the potential transaction and all materials of any kind (including tax

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opinions and other tax analyses) provided to the Company relating to that treatment and structure, without the Purchasers’ imposing any limitation of any kind. However, any information relating to the tax treatment and tax structure shall remain confidential (and the foregoing sentence shall not apply) to the extent necessary to enable any person to comply with securities laws. For this purpose, “tax treatment” means US federal and state income tax treatment, and “tax structure” is limited to any facts that may be relevant to that treatment.

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If the foregoing is in accordance with your understanding, please sign and return to us four counterparts hereof, and upon the acceptance hereof by you, on behalf of each of the Purchasers, this letter and such acceptance hereof shall constitute a binding agreement among each of the Purchasers and the Company. It is understood that your acceptance of this letter on behalf of each of the Purchasers is pursuant to the authority set forth in a form of Agreement among Purchasers, the form of which shall be submitted to the Company for examination upon request, but without warranty on your part as to the authority of the signers thereof.

Very truly yours,
ULTRA PETROLEUM CORP.
By:	/s/ Michael D. Watford
	Name: Michael D. Watford
	Title: Chairman, President & CEO

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Accepted as of the date hereof:

Goldman, Sachs & Co.
By:	/s/ Michael Hickey
	(Goldman, Sachs & Co.)
	Name: Michael Hickey
	Title: Managing Director
	On behalf of each of the Purchasers

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