UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No.     )*

Earthstone Energy, Inc.

(Name of Issuer)

Common Stock, par value $0.001 per share

(Title of Class of Securities)

27032D205

(CUSIP Number)

Ron Hulme

Parallel Resource Partners, LLC

700 Louisiana St., 50^th Floor

Houston, Texas 77002

(713) 238-9500

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

with a copy to:

J. Mark Metts

Sidley Austin LLP

1000 Louisiana St., Suite 6000

Houston, Texas 77002

(713) 495-4501

October 16, 2014

(Date of Event which Requires Filing of this Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box.      ¨

Note: Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See Rule 13d-7 for other parties to whom copies are to be sent.

The information required in the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

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This Schedule 13D (this “Schedule 13D”) relates to the common stock, $0.001 par value per share (the “Common Stock”), of Earthstone Energy, Inc., a Delaware corporation (the “Issuer” or “Earthstone”), whose principal executive offices are located at 633 Seventeenth Street, Suite 2320, Denver, Colorado 80202.

This Schedule 13D is being filed jointly by and on behalf of each of the following entities/persons (collectively, the “Reporting Persons”):

SCHEDULE 13D

The entities listed at (i) through (vii) are referred to herein collectively as the “Parallel Entities”. The entities and individuals listed at (ix) through (xi) are referred to herein collectively as the “Bluescape Persons” and the entities and individuals listed at (xii) through (xiv) are referred to herein as the “Carlson Persons”. The individuals listed at (xv) through (xvi) above are referred to herein as the “CEP I Persons”.

The name, citizenship, present principal occupation or employment and business address of each director and executive officer of ERR FI Ltd. and Carlson Corp are set forth in Appendix A attached hereto.

The principal business of each of the Parallel Entities is to invest in securities. The principal business of Parallel is to serve as the investment manager of the Parallel Entities. The principal business of each of BEP and CEP I is to manage the business of Parallel. The principal business of Bluescape Resources is to manage BEP and to invest in private oil and gas assets. The principal occupation of Mr. C. John Wilder Jr., is to serve as the Executive Chairman of Bluescape Resources. The principal business of Carlson Corp is to serve as a manager of CEP I. The principal occupation of Mr. Clint D. Carlson is serving as President of Carlson Capital, L.P., a Delaware limited partnership and an affiliate of Carlson Corp, the principal business of which is to serve as an investment manager. The principal occupation of both Mr. Ron Hulme and Mr. John K. Howie is to serve as a member of the board of managers of Parallel.

The principal business address of the Parallel Entities, Parallel and the CEP I Persons is 700 Louisiana St., 50th Floor Houston, Texas 77002. The principal business address of the Bluescape Persons is 200 Crescent Ct. #200, Dallas, Texas 75201. The principal business address of the Carlson Persons and Carlson Capital, L.P. is 2100 McKinney Avenue, Suite 1800, Dallas, TX 75201.

None of the Reporting Persons has, during the last five years, been convicted in a criminal proceeding (excluding traffic violations or similar misdemeanors).

None of the Reporting Persons has, during the last five years, been a party to a civil proceeding of a judicial or administrative body of competent jurisdiction and, as a result of such proceeding, was or is subject to a judgment, decree or final order enjoining future violations of, or prohibiting or mandating activities subject to, federal or state securities laws or finding any violation with respect to such laws.

On October 16, 2014, Flatonia, Parallel, Sabine River Energy, LLC (“Sabine”), Oak Valley Operating LLC (“Oak Valley Operator”), Oak Valley Resources, LLC (“Oak Valley”) and the Issuer entered into a Contribution Agreement (the “Contribution Agreement”). Concurrently with entering into, and in order to induce Flatonia to enter into, the Contribution Agreement, Oak Valley entered into an Amended and Restated Voting Agreement dated as of October 16, 2014 (the “Amended Voting Agreement”), with Ray Singleton, Chairman of the Board of Directors of the Issuer, President and Chief Executive Officer of the Issuer, and a significant stockholder of the Issuer (the “Voting Agreement Stockholder”), with respect to all of the shares of Common Stock that are currently or will be beneficially owned by the Voting Agreement Stockholder (“Voting Agreement Shares”). Flatonia is a third party beneficiary of the Amended Voting Agreement as described in more detail in Item 4 below. The shares of Common Stock to which this Schedule 13D relates have not been purchased by Flatonia, and no funds were expended in connection with the execution of either the Contribution Agreement or the Amended Voting Agreement.

SCHEDULE 13D

Contribution Agreement

On October 16, 2014, the Issuer, Oak Valley, Flatonia, Parallel, Sabine and Oak Valley Operator entered into the Contribution Agreement. Currently, Flatonia owns a 70% undivided interest, and an Oak Valley subsidiary owns a 30% undivided interest, in an Eagle Ford horizontal development project, which is operated by Oak Valley Operator (such properties, the “Properties”). The Contribution Agreement provides that, upon the terms and subject to the conditions set forth in the Contribution Agreement, Flatonia will contribute to Sabine (which will then be wholly owned by Earthstone, as described below) a 20% undivided ownership interest in the Properties (the “Contribution”) in exchange for the issuance by Earthstone to Flatonia of shares of Common Stock, as described below. After the Contribution, Flatonia will continue to hold a 50% undivided interest in the Properties, and Sabine, which will then be owned by the Issuer, will hold the remaining 50%.

The closing of the Contribution is subject to the closing of the transactions contemplated by that certain Exchange Agreement, dated May 15, 2014 and as amended as of September 26, 2014, between the Issuer and Oak Valley (the “Exchange Agreement”), as referenced in the Issuer’s Current Reports on Form 8-K filed on May 16 and October 2, 2014 with the U.S. Securities and Exchange Commission (the “SEC”). Pursuant to the Exchange Agreement, Oak Valley will contribute to the Issuer the membership interests of its three subsidiaries, including Oak Valley Operator and Sabine, including Sabine’s interest in the Properties, in exchange for the issuance of 9,124,452 shares of Common Stock to Oak Valley (the “Exchange”).

In consideration for the Contribution, Earthstone will issue to Flatonia at the closing of the Contribution that number of shares of Common Stock equal to 21.4% of the outstanding shares of Common Stock, on an as-converted, as-exercised basis after giving effect to the Exchange and the Contribution (the “Contribution Shares”).

In order for Flatonia to achieve this 21.4% ownership, Earthstone will be required to issue 2,957,304 shares of Common Stock to Flatonia at the closing of the Contribution, which number (i) is based on the 1,737,420 shares of Common Stock represented by the Issuer to be outstanding on the date of the Contribution Agreement and (ii) assumes that 9,124,452 shares of Common Stock are issued to Oak Valley pursuant to the Exchange Agreement.

After giving effect to the transactions contemplated by the Exchange Agreement and the Contribution Agreement, current stockholders of the Issuer will own 12.6%, Oak Valley will own 66.0%, and Flatonia will own 21.4%, respectively, of the Issuer’s then outstanding Common Stock.

The Contribution Agreement and the Contribution have been approved by the board of directors of Earthstone (the “Earthstone Board”) and the board of managers of each of Oak Valley, Flatonia and Parallel.

Because the closing of the Contribution is subject to (i) approval by Earthstone’s stockholders of the issuance of the Contribution Shares to Flatonia, (ii) the closing of the transactions contemplated by the Exchange Agreement (which is itself subject to closing conditions, including the approval by Earthstone’s stockholders of the issuance of shares of Common Stock to Oak Valley) and (iii) other customary closing conditions, neither Flatonia nor any of the other Reporting Persons will have beneficial ownership of any of the Contribution Shares until the closing of the Contribution.

Under the Contribution Agreement, if the Contribution is consummated, Flatonia is entitled to designate one person to serve on the Earthstone Board as long as Flatonia continues to own at least 7.5% of the outstanding Earthstone Common Stock. If Flatonia does not exercise its right to designate a director, then Flatonia may elect instead to designate a Board observer, who would not be a director and would not have voting rights. If the Contribution is consummated and Flatonia exercises its Board designation right, the Earthstone Board will be increased to eight members. Flatonia has informed Earthstone that it does not intend to designate a person to serve on the Earthstone Board at this time or in the foreseeable future.

SCHEDULE 13D

Amended Voting Agreement

On October 16, 2014, the Voting Agreement Stockholder and Oak Valley entered into the Amended Voting Agreement. Flatonia is a third party beneficiary of the Amended Voting Agreement. During the term of the Amended Voting Agreement, the Voting Agreement Stockholder has agreed, among other things, to (1) vote all Voting Agreement Shares in favor of the approval of the Exchange, the issuance of the Contribution Shares, the approval and adoption of the Exchange Agreement and the approval of any other transactions contemplated by the Exchange Agreement or the Contribution Agreement; (2) subject to certain exceptions, not sell or transfer the Voting Agreement Shares until the Amended Voting Agreement terminates; and (3) not enter into any other voting arrangement with respect to the Voting Agreement Shares or take any other action that would restrict, limit or interfere with the performance of his obligations under the Amended Voting Agreement. With respect to the obligations to vote on the Contribution Agreement, the Amended Voting Agreement terminates (a) at the closing of the Contribution or (b) if the Contribution Agreement is terminated in accordance with its terms. The Amended Voting Agreement also includes the grant by the Voting Agreement Stockholder of an irrevocable proxy to Frank A. Lodzinski, President and Chief Executive Officer of Oak Valley (and any other individual who may be designated by Oak Valley) to vote and exercise all voting rights with respect to the matters described above. Flatonia has not been granted a proxy directly, but it is a third party beneficiary of the Amended Voting Agreement and the proxy granted thereunder.

The foregoing descriptions of the Contribution Agreement and the Amended Voting Agreement do not purport to be complete and are qualified in their entirety by reference to the Contribution Agreement and the Amended Voting Agreement, which are filed as Exhibit B and Exhibit C hereto, respectively, and incorporated herein by reference.

Existing Joint Operating Agreement

If the Exchange and the Contribution are consummated, the Issuer’s interest in the Properties will represent approximately 56% of the proved reserves of the Issuer, based on the December 31, 2013 reserve estimates. The Properties are currently subject to a joint operating agreement (the “JOA”) with Flatonia. The JOA gives Flatonia a right to consent to any sale by Sabine of its interest in the Properties (which consent may be withheld if Flatonia does not believe the transferee has sufficient financial or technical capacity). The JOA also gives Flatonia a preferential purchase right to acquire the Properties should Sabine elect to sell its interest. The JOA further gives Flatonia the right to “tag along” in the event of a disposition of Sabine’s interest and include Flatonia’s interest in such disposition. All three of these provisions (i.e., the consent, preferential purchase and tag-along rights) are triggered by a direct sale by Sabine of its interests or a direct or indirect change of control of Sabine, which includes a change of control of Sabine’s owner.

In addition, the JOA includes a “drag-along” provision, which obligates Sabine to sell its interest in the Properties to a third-party buyer concurrently with a sale by Flatonia of its interest in the Properties. (If an Amended JOA is executed in connection with the Contribution, as described below, this provision will only apply to a 20% undivided interest held by Sabine.) If this provision were exercised, the Issuer may be obligated to sell the Properties at a price that it considers to be insufficient or at a time or on terms and conditions that it deems unattractive.

Amended Joint Operating Agreement

The Contribution Agreement provides that, at the closing of the Contribution, Sabine, Flatonia and Oak Valley Operator will enter into an amended JOA (the “Amended JOA”) that includes terms in addition to or in lieu of the ones described above. The Amended JOA will set forth the obligations of Sabine, Flatonia and Oak Valley Operator with respect to the day-to-day operations of the Properties.

SCHEDULE 13D

The Amended JOA contains industry standard terms and provisions, and provides, among other things, that (i) Oak Valley Operator will be the party designated as the “Operator” of the Properties and, as such, will have full control of the Properties, subject to any limitations specifically contained in the Amended JOA and (ii) the costs and liabilities incurred in connection with exploring, developing and operating the Properties will be borne by the parties to the Amended JOA in proportion to their applicable ownership interests.

The Amended JOA includes an Area of Mutual Interest (the “AMI”) covering the area depicted on Exhibit A to the Amended JOA (the “Contract Area”). In the event that Oak Valley, the Issuer, Flatonia Holdings, or any of their subsidiaries acquires, directly or indirectly, an interest within the AMI, the Amended JOA provides that each non-acquiring party will have the option to participate for its proportionate share in such acquisition.

In the event that any party to the Amended JOA elects not to participate in the first well within a drilling unit (or, if such well is not located within a drilling unit, the first well on an oil and gas lease), such non-participating party must assign its working interest and net revenue interest in the applicable lease (or the applicable leases covered by such drilling unit in which such well is drilled) to the parties to the Amended JOA participating in that well. The non-participating party will be paid $2,000 per net mineral acre for such assignment.

The Amended JOA contains restrictions on the ability of Sabine to dispose of its interest in the Properties and, in certain instances, Sabine could be required to sell a portion of its interest in the Properties along with Flatonia. Sabine may not make a “Disposition” (as defined in the Amended JOA) of its interest in the Properties without Flatonia’s consent, which may be withheld if Flatonia reasonably believes the proposed buyer does not have the requisite financial capability or technical expertise to fulfill obligations under the Amended JOA. However, Flatonia will not have a consent right with respect to a Change of Control (as defined in the Amended JOA) of the Issuer. Flatonia also will have a right of first refusal in the event Sabine desires to “Dispose” (as defined in the Amended JOA) of its interest in the Properties in connection with any transaction other than a bona fide public company transaction at the Issuer level or resulting in a change in beneficial ownership of the Issuer. If Flatonia desires to Dispose of some or all of its interest, it is required to provide Operator with notice and give Operator and its affiliates 60 days to negotiate and enter into a purchase and sale agreement with Flatonia. If no agreement is reached, Flatonia may freely enter into negotiations with third parties and, if Flatonia is Disposing of 100% of its interests in the Properties, it can exercise certain drag-along rights. Flatonia’s drag-along rights permit it to require Sabine to sell some of its interests in the Properties, though Sabine has the right to retain up to a 30% non-operated interest in the Properties. The Amended JOA also contains tag-along rights in the event that any party to the Amended JOA receives an offer to Dispose of all or a portion of its interest in the Properties.

However, in connection with a bona fide public company transaction at the Issuer level or resulting in a change in beneficial ownership of the Issuer, in lieu of tag-along rights, Flatonia will have the option to cause the Issuer to acquire its interest in the Properties at fair market value in connection with the consummation of the bona fide public company transaction. The Amended JOA also restricts Operator’s ability to directly or indirectly transfer operatorship. Under the Amended JOA, the Exchange is not considered a Change of Control or Disposition of Sabine or Operator.

Operator may resign at any time upon written notice and shall be deemed to have resigned if (i) it terminates its legal existence, (ii) Sabine fails to own at least a 50% undivided interest in the Properties or (iii) if Operator is no longer capable of serving as operator. In addition, Operator may be removed if certain removal events occur, including a Change of Control of the Issuer, Operator or Sabine and certain significant changes in the management team of the Issuer. In the event that Flatonia sells all of its interests in the Properties, Flatonia may require Operator to resign and support the buyer to become the operator under the Amended JOA.

SCHEDULE 13D

As long as Flatonia owns at least a 50% interest in the Contract Area, then in those instances under the Amended JOA in which the approval of the majority of the interest owners is required, Flatonia’s vote will be deemed to constitute a majority (i.e., even if it owns exactly 50%).

The Amended JOA will be effective as of the closing of the Contribution.

The Amended JOA will remain in full force and effect so long as any of the “Oil and Gas Leases” (as defined in the Amended JOA) remain or are continued in force with respect to the Contract Area. However, if Flatonia sells all of its interests in the Contract Area to a third party, and such third party becomes Operator, certain provisions of the Amended JOA will terminate.

Registration Rights Agreement

At the closing of the Contribution, the Issuer, Parallel, Flatonia and Oak Valley will enter into a registration rights agreement (the “Registration Rights Agreement”) requiring the Issuer to register, at its cost, with the SEC the resale of the Contribution Shares at the request of Flatonia, Parallel or any affiliate of Parallel to which Flatonia, Parallel or any affiliate thereof has transferred shares of Common Stock (collectively, the “Flatonia Stockholders”).

The Registration Rights Agreement will terminate after the third anniversary of the closing of the transactions contemplated by the Contribution Agreement. The Flatonia Stockholders owning a majority of the “Registrable Securities” (as defined in the Registration Rights Agreement) may request registration no more than two times, and no more frequently than once in any six-month period, of shares having an estimated offering price of greater than $5 million. With certain exceptions, the Issuer must file and have the registration statement declared effective and must maintain the effectiveness of the registration statement for nine months or such shorter period if all shares have been sold.

At any time following the six-month anniversary of the closing of the Contribution, if the Issuer is eligible to use a Form S-3 to register its securities for resale, then the Flatonia Stockholders owning a majority of the Registrable Securities may require the Issuer to file a shelf registration statement on Form S-3. The shelf registration statement must be filed within 20 days after the Issuer receives the request. The Issuer may also permit other persons, including Oak Valley, to register shares on the shelf registration statement. At any time during the term of the Registration Rights Agreement, the Flatonia Stockholders owning a majority of the Registrable Securities registered pursuant to a shelf registration statement may request that a public offering be made under the shelf registration statement if the aggregate proceeds of such sale are expected to equal or exceed $3 million.

If the Issuer files a registration statement, it must offer to the Flatonia Stockholders the opportunity to include the resale of their Registrable Securities in such registration statement, subject to customary qualifications and limitations.

The Issuer is prohibited from entering into or amending any registration rights agreements or other agreements that violate or are detrimental to rights granted to the Flatonia Stockholders in the Registration Rights Agreement. Additionally, Oak Valley, Parallel, Flatonia and the Issuer have all agreed that the registration rights granted to Oak Valley in connection with the Exchange Agreement are, subject to the provisions of both the Flatonia and Oak Valley registration rights agreements, pari passu with the rights of the Flatonia Stockholders to register their shares of Common Stock.

The Flatonia Stockholders have agreed that they will not, without the Issuer’s prior written consent, during the period commencing on the closing date of the Contribution Agreement and ending on the one year anniversary thereof (the “lock-up period”), sell or transfer any Registrable Securities. However, the foregoing restriction does not apply to: (i) sales or transfers to Parallel or any affiliate of Parallel; (ii) the ability of the Flatonia Stockholders to exercise their piggy-back registration rights in connection with the sale of Common Stock by any “Stockholder” (as defined in the Oak Valley Registration Rights Agreement entered into in connection with the Exchange Agreement), whether upon exercise of its own demand registration rights, piggy-back registration rights or otherwise; or (iii) the ability of the Flatonia Stockholders to exercise their tag-along rights, as described below.

SCHEDULE 13D

If, during the lock-up period, any “Stockholder” (as defined in the Oak Valley Registration Rights Agreement entered into in connection with the Exchange Agreement) proposes or agrees to transfer all or a portion of its shares of Common Stock (including beneficial ownership with respect thereto) that are not sold as part of a public offering (excluding certain small transfers to family members for estate planning purposes), then each Flatonia Stockholder will have the right to participate in such transfer as provided in the Registration Rights Agreement.

(a) and (b). The responses of the Reporting Persons to rows 7 through 13 on the cover pages of this Schedule 13D are incorporated by reference herein.

1. As of the date hereof, the Reporting Persons do not own any shares of Common Stock. However, because of the Voting Agreement Stockholder’s obligations under the Amended Voting Agreement, Flatonia, as a third party beneficiary of those obligations, may be deemed to have shared voting power to vote up to an aggregate of 453,360 shares of Common Stock in favor of the approval of the Exchange, the issuance of the Contribution Shares, the Exchange Agreement and the other transactions contemplated by the Exchange Agreement and the Contribution Agreement. Thus, for purposes of Rule 13d-3 promulgated under the Securities Exchange Act of 1934, as amended (the “Exchange Act”), Flatonia and the other Reporting Persons may be each deemed to be the beneficial owner of an aggregate of 453,360 shares of Common Stock. Flatonia is not a direct party to the Amended Voting Agreement, but it is a third party beneficiary of the Amended Voting Agreement and the proxy granted thereunder.

These shares of Common Stock subject to the Amended Voting Agreement represent 26.1% of the outstanding shares of the Issuer’s outstanding Common Stock, based on a total of 1,737,420 shares of Common Stock outstanding as of August 11, 2014, as reported in the Issuer’s Form 10-Q for the fiscal period ended June 30, 2014. In the Contribution Agreement, the Issuer represented to Flatonia that, as of the date of the Contribution Agreement, the number of shares of outstanding Common Stock had not changed from the amount reported in such Form 10-Q.

The filing of this statement on Schedule 13D shall not be construed as an admission that the Reporting Persons are for the purposes of Section 13(d) or 13(g) of the Exchange Act, the beneficial owner of any of the shares of Common Stock. Pursuant to Rule 13d-4, the Reporting Persons disclaim all such beneficial ownership.

2. Flatonia Holdings owns, directly and indirectly, 100% of the membership interests of Flatonia.

3. ERR owns 41.1%, ERR FI Flatonia Holdings owns 3.3% and ERR FI Flatonia Intermediate owns 14.2%, in each case, of the membership interests of Flatonia Holdings.

4. ERR FI Ltd. owns 100% of the membership interests of ERR FI Flatonia Holdings, and ERR FI owns 100% of the issued and outstanding shares of stock of ERR FI Ltd.

5. As set forth above, ERR, ERR FI and ERR FI II Flatonia Intermediate (collectively, the “ERR Entities”) own 58.6% of the membership interests of Flatonia Holdings. Parallel serves as the general partner of, and has the power to direct the affairs of, each of the ERR Entities. Parallel also serves as the manager of Flatonia Holdings and owns, directly or indirectly, 1.5% of the membership interests of Flatonia Holdings. The board of managers of Parallel consists of Clint D. Carlson, C. John Wilder, Jr., Ron Hulme,
John K. Howie, and Jonathan Siegler.

SCHEDULE 13D

6. Together, CEP I and BEP have the power to direct the affairs of Parallel. Additionally, CEP I and BEP each own 50% of the outstanding membership interests of Parallel. Together, Carlson Corp, Ron Hulme and John K. Howie form the board of managers CEP I and have the power to direct its affairs. Collectively, Carlson Corp, Ron Hulme and John Howie own 100% of the membership interests of CEP I. Mr. Clint D. Carlson has the power to direct the affairs of Carlson Corp, as its President. Bluescape Resources owns 100% of the membership interests of BEP and has the power to direct the affairs of BEP. Mr. C. John Wilder, Jr. has the power to direct the affairs of Bluescape Resources as its Executive Chairman.

(c) Except as set forth in this Schedule 13D with reference to the Contribution Agreement and the Amended Voting Agreement, none of the Reporting Persons or, to their knowledge, any of its directors or executive officers, has effected any transaction in the shares of Common Stock during the past 60 days.

(d) The Reporting Persons have no right to receive dividends from, or the proceeds from the sale of, the Voting Agreement Shares. The Reporting Persons will have no pecuniary interest in shares of Common Stock unless and until the transactions contemplated by the Contribution Agreement are consummated.

(e) Not applicable.

Contribution Agreement and Related Agreements

The description of the Contribution Agreement, the Amended Voting Agreement, the Registration Rights Agreement the JOA and the Amended JOA in Item 4 are hereby incorporated into this Item 6 by reference. The copy of the Contribution Agreement filed as Exhibit B hereto and the copy of the Amended Voting Agreement filed as Exhibit C hereto are incorporated by reference herein.

Amendment to Rights Agreement

On October 16, 2014, immediately prior to the execution and delivery of the Contribution Agreement and the Amended Voting Agreement, and in order to induce Flatonia to enter into the Contribution Agreement, Earthstone entered into the Third Amendment to Earthstone’s Rights Agreement, dated February 4, 2009 and as amended by the First Amendment to the Rights Agreement dated May 15, 2014 and the Second Amendment to the Rights Agreement dated May 15, 2014 (the “Earthstone Rights Agreement”). The Earthstone Rights Agreement sets forth the terms under which the Issuer would issue preferred share purchase rights (the “Earthstone Rights”).

The primary purposes of the Third Amendment to the Earthstone Rights Agreement are to:

SCHEDULE 13D

Joint Filing Agreement

The Reporting Persons are parties to an agreement with respect to the joint filing of this Schedule 13D and any amendments thereto. A copy of such agreement is filed as Exhibit A hereto and is incorporated by reference herein.

Except as set forth herein, there are no contracts, understandings or relationships among the Reporting Persons or between the Reporting Persons and any other person with respect to the Common Stock.

SCHEDULE 13D

SIGNATURES

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement on Schedule 13D is true, complete and correct.

Date: October 27, 2014

SCHEDULE 13D

SCHEDULE 13D

Attention: Intentional misstatements or omissions of act constitute federal violations (see 18 U.S.C. 1001).

SCHEDULE 13D

Appendix A

DIRECTORS AND EXECUTIVE OFFICERS OF ERR FI LTD. AND CARLSON CORP

The following sets forth the name, position, principal occupation, and principal business address of each director and executive officer of Energy Recapitalization and Restructuring FI, Ltd. and Carlson Energy Partners I, LLC, respectively. To the best of the Reporting Persons’ knowledge, except as set forth in this Schedule 13D, none of the directors or executive officers of Energy Recapitalization and Restructuring FI, Ltd. or Carlson Energy Partners I, LLC owns any Common Stock.

ERR FI LTD.

CARLSON CORP.

SCHEDULE 13D

EXHIBIT A

JOINT FILING AGREEMENT

The undersigned acknowledge and agree that the foregoing statement on Schedule 13D is filed on behalf of each of the undersigned and that all subsequent amendments to this statement on Schedule 13D shall be filed on behalf of each of the undersigned without the necessity of filing additional joint filing agreements. The undersigned acknowledge that each shall be responsible for the timely filing of such amendments, and for the completeness and accuracy of the information concerning him or it contained herein and therein, but shall not be responsible for the completeness and accuracy of the information concerning the others, except to the extent that he or it knows or has reason to believe that such information is inaccurate.

DATE: October 27, 2014

SCHEDULE 13D

SCHEDULE 13D

EXHIBIT C

AMENDED AND RESTATED

VOTING AGREEMENT

THIS AMENDED AND RESTATED VOTING AGREEMENT (this “Agreement”), is dated as of October 16, 2014 by and between Oak Valley Resources, LLC, a Delaware limited liability company (the “Company”), and Ray Singleton (“Stockholder”).

WHEREAS, Stockholder is, as of the date hereof, the record and beneficial owner of that number of shares of common stock, $0.001 par value per share (the “Earthstone Common Stock”), of Earthstone Energy, Inc., a Delaware corporation (“Earthstone”), set forth opposite Stockholder’s name on Schedule A hereto;

WHEREAS, effective as of May 15, 2014, Earthstone and the Company entered into that certain Exchange Agreement, (as the same may be amended or supplemented, the “Exchange Agreement”), providing for, among other things, the exchange of Earthstone Common Stock for the membership interests of the Oak Valley Subsidiaries (the “Exchange”), upon the terms and subject to the conditions set forth in the Exchange Agreement (capitalized terms used and not otherwise defined herein shall have the meanings attributed thereto in the Exchange Agreement) and, in order to induce the Company to enter into the Exchange Agreement, Stockholder and the Company concurrently entered into a Voting Agreement (the “Original Voting Agreement”); and

WHEREAS, concurrently with the execution and delivery of this Agreement, Earthstone and the Company have entered into a Contribution Agreement (as the same may be amended and supplemented, the “Contribution Agreement”), by and among the Company, Earthstone, Flatonia Energy, LLC, a Delaware limited liability company (“Flatonia”), Parallel Resource Partners, LLC, Oak Valley Operating, LLC and Sabine River Energy, LLC, providing for the issuance of Earthstone Common Stock to Flatonia, upon the terms and subject to the conditions set forth in the Contribution Agreement (the “Contribution Agreement Share Issuance”); and

WHEREAS, Stockholder and the Company desire to amend and restate the Original Agreement to include (i) the approval of the Contribution Agreement Share Issuance in Sections 3 and 4 hereof and (ii) Flatonia as a third party beneficiary hereof; and

WHEREAS, as a condition to the willingness of the Company to enter into the Contribution Agreement, and in order to induce the Company to enter into the Contribution Agreement, Stockholder has agreed to enter into this Agreement.

NOW, THEREFORE, in consideration of the execution and delivery by the Company of the Contribution Agreement and the mutual representations, warranties, covenants and agreements contained herein, and other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the parties hereto hereby amend and restate the Original Voting Agreement as follows:

Section 1. Representations and Warranties of Stockholder. Stockholder hereby represents and warrants to the Company as follows:

(a) Stockholder is the beneficial owner (within the meaning of Rule 13d-3 under the Securities Exchange Act of 1934, as amended (the “Exchange Act”)) and unless otherwise indicated, the record owner of the shares of Earthstone Common Stock (as may be adjusted from time to time pursuant to Section 5 hereof, the “Shares”) set forth opposite Stockholder’s name on Schedule A to this Agreement and such Shares represent all of the shares of Earthstone Common Stock beneficially owned by Stockholder as of the date hereof. For purposes of this Agreement, the term “Shares” shall include any shares of Earthstone Common Stock issuable to Stockholder upon exercise or conversion of any existing right, contract, option, or warrant to purchase, or securities convertible into or exchangeable for, Earthstone Common Stock (“Stockholder Rights”) that are currently exercisable or convertible or become exercisable or convertible and any other shares of Earthstone Common Stock Stockholder may acquire or beneficially own during the term of this Agreement.

(b) Stockholder has all requisite power and authority to execute and deliver this Agreement and to consummate the transactions contemplated hereby. This Agreement has been validly executed and delivered by Stockholder and, assuming that this Agreement constitutes the legal, valid and binding obligation of the Company, constitutes the legal, valid and binding obligation of Stockholder, enforceable against Stockholder in accordance with its terms (except insofar as enforceability may be limited by applicable bankruptcy, insolvency, reorganization, moratorium or similar laws affecting creditors’ rights generally, or by principles governing the availability of equitable remedies).

(c) The execution and delivery of this Agreement by Stockholder does not, and the performance of this Agreement by Stockholder will not, (i) conflict with any agreement, arrangement or understanding to which Stockholder is a party or is bound, (ii) conflict with or violate any judgment, order, decree, statute, law, ordinance, rule or regulation applicable to Stockholder or by which he is bound or affected, (iii)(A) result in any breach of or constitute a default (or an event that with notice or lapse of time or both would become a default) under, (B) give to any other person any rights of termination, amendment, acceleration or cancellation of, or (C) result in the creation of any pledge, claim, lien, charge, encumbrance or security interest of any kind or nature whatsoever upon any of the properties or assets of Stockholder under, any agreement, contract, indenture, note or instrument to which Stockholder is a party or by which it is bound or affected, except, in the case of clause (i), (ii) or (iii), for such conflicts, breaches, defaults or other occurrences that would not prevent or materially delay the performance by Stockholder of any of Stockholder’s obligations under this Agreement, or (iv) except for applicable requirements, if any, of the Exchange Act, the Securities Act of 1933, as amended (the “Securities Act”), the NYSE MKT (the “NYSE MKT”), require any filing by Stockholder with, or any permit, authorization, consent or approval of, any governmental or regulatory authority, except where the failure to make such filing or obtain such permit, authorization, consent or approval would not prevent or materially delay the performance by Stockholder of any of Stockholder’s obligations under this Agreement.

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(d) The Shares and the certificates representing the Shares owned by Stockholder are now and at all times during the term hereof will be held by Stockholder, or by a nominee or custodian for the benefit of Stockholder, free and clear of all pledges, liens, charges, claims, security interests, proxies, voting trusts or agreements, understandings or arrangements or any other encumbrances whatsoever, except for any such encumbrances or proxies arising hereunder or under applicable federal and state securities laws. Stockholder owns of record or beneficially no shares of Earthstone Common Stock other than Stockholder’s Shares.

(e) As of the date hereof, neither Stockholder, nor any of his properties or assets is subject to any order, writ, judgment, injunction, decree, determination or award that would prevent or delay the consummation of the transactions contemplated hereby.

(f) Stockholder understands and acknowledges that the Company is entering into the Exchange Agreement in reliance upon Stockholder’s execution and delivery of this Agreement.

(g) Stockholder understands and acknowledges that the Company and Flatonia are entering into the Contribution Agreement in reliance upon Stockholder’s execution and delivery of this Agreement.

Section 2. Representations and Warranties of the Company. The Company hereby represents and warrants to Stockholder as follows:

(a) The Company is a limited liability company duly organized, validly existing and in good standing under the laws of the jurisdiction of its incorporation. The Company has all requisite power and authority to execute and deliver this Agreement, to perform its obligations hereunder and to consummate the transactions contemplated hereby, and has taken all necessary corporate action to authorize the execution, delivery and performance of this Agreement. This Agreement has been duly executed and delivered by the Company, and assuming that this Agreement constitutes the legal, valid and binding obligation of Stockholder, constitutes the legal, valid and binding obligation of the Company, enforceable against the Company in accordance with the terms of this Agreement (except insofar as enforceability may be limited by applicable bankruptcy, insolvency, reorganization, moratorium or similar laws affecting creditors’ rights generally, or by principles governing the availability of equitable remedies).

(b) The execution and delivery of this Agreement by the Company does not, and the performance of this Agreement by the Company will not, (i) conflict with the certificate of organization or operating agreement of the Company as presently in effect, (ii) conflict with or violate any judgment, order, decree, statute, law, ordinance, rule or regulation applicable to the Company or by which it is bound or affected, (iii) (A) result in any breach of or constitute a default (or an event that with notice or lapse of time or both would become a default) under, (B) give to any other person any rights of termination, amendment, acceleration or cancellation of, or (C) result in the creation of any pledge, claim, lien, charge, encumbrance or security interest of any kind or nature whatsoever upon any of the properties or assets of the Company under, any agreement,

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contract, indenture, note or instrument to which the Company is a party or by which it is bound or affected, except, in the case of clause (i), (ii) or (iii), for such conflicts, breaches, defaults or other occurrences that would not prevent or materially delay the performance by the Company of its obligations under this Agreement, or (iv) except for applicable requirements, if any, of the Exchange Act, the Securities Act or the NYSE MKT, require any filing by the Company with, or any permit, authorization, consent or approval of, any governmental or regulatory authority, except where the failure to make such filing or obtain such permit, authorization, consent or approval would not prevent or materially delay the performance by the Company of its obligations under this Agreement.

(c) As of the date hereof, neither the Company nor any of its properties or assets is subject to any order, writ, judgment, injunction, decree, determination or award that would prevent or delay the consummation of the transactions contemplated hereby.

Section 3. Covenants of Stockholder. Stockholder agrees as follows:

(a) Stockholder shall not, except as contemplated by the terms of this Agreement, sell, transfer, pledge, assign or otherwise dispose of, or enter into any contract, option or other arrangement (including any profit-sharing arrangement) or understanding with respect to the sale, transfer, pledge, assignment or other disposition of, the Shares (including any options or warrants to purchase Earthstone Common Stock) to any person (any such action, a “Transfer”). For purposes of clarification, the term “Transfer” shall include, without limitation, any short sale (including any “short sale against the box”), pledge, transfer, and the establishment of any open “put equivalent position” within the meaning of Rule 16a-1(h) under the Exchange Act. Notwithstanding the foregoing, (i) Transfers of Shares as bona fide gifts, or (ii) distributions of Shares to affiliates, affiliated partnerships or other affiliated entities of the undersigned, shall not be prohibited by this Agreement; provided that in the case of any such transfer or distribution pursuant to clause (i) or (ii), each donee or distributee shall execute and deliver to the Company a valid and binding counterpart to this Agreement.

(b) Stockholder shall not, except as contemplated by the terms of this Agreement (i) enter into any voting arrangement, whether by proxy, voting agreement, voting trust, power-of-attorney or otherwise, with respect to the Shares or (ii) take any other action that would in any way restrict, limit or interfere with the performance of his obligations hereunder or the transactions contemplated hereby or make any representation or warranty of Stockholder herein untrue or incorrect in any material respect.

(c) At any meeting of stockholders of Earthstone called to vote upon the Exchange or in connection with any stockholder consent in respect of a vote on the Exchange, the Contribution Agreement Share Issuance, the Exchange Agreement or any other transaction contemplated by the Exchange Agreement or the Contribution Agreement or at any adjournment thereof or in any other circumstances upon which a vote, consent or other approval (including by written consent) with respect to such matters is sought, Stockholder shall vote (or cause to be voted), or shall consent, execute a consent or cause to be executed a consent in respect of, Stockholder’s Shares in favor of the Exchange, the Contribution Agreement Share Issuance, the adoption by Earthstone of the Exchange Agreement and the approval of any other transactions contemplated by the Exchange Agreement or the Contribution Agreement.

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(d) Stockholder agrees to permit Earthstone to publish and disclose in the Proxy Statement and related filings under the securities laws Stockholder’s identity and ownership of Shares and the nature of its commitments, arrangements and understandings under this Agreement and any other information required by applicable law.

Section 4. Grant of Irrevocable Proxy; Appointment of Proxy.

(a) Stockholder hereby irrevocably grants to, and appoints, Frank A. Lodzinski, and any other individual who shall hereafter be designated by the Company, Stockholder’s proxy and attorney-in-fact (with full power of substitution), for and in the name, place and stead of Stockholder, to vote Stockholder’s Shares, or grant a consent or approval in respect of such Shares, at any meeting of stockholders of Earthstone or at any adjournment thereof or in any other circumstances upon which their vote, consent or other approval is sought, in favor of the Exchange, the Contribution Agreement Share Issuance, the adoption by Earthstone of the Exchange Agreement and the approval of the other transactions contemplated by the Exchange Agreement or the Contribution Agreement.

(b) Stockholder represents that any existing proxies given in respect of Stockholder’s Shares are not irrevocable, and that any such proxies are hereby revoked.

(c) Stockholder hereby affirms that the irrevocable proxy set forth in this Section 4 is given in connection with the execution of the Exchange Agreement and the Contribution Agreement, and that such irrevocable proxy is given to secure the performance of the duties of Stockholder under this Agreement. Stockholder hereby further affirms that the irrevocable proxy is coupled with an interest and may under no circumstances be revoked, except upon termination of this Agreement pursuant to Section 7. Stockholder hereby ratifies and confirms all that such irrevocable proxy may lawfully do or cause to be done by virtue hereof. Such irrevocable proxy is executed and intended to be irrevocable in accordance with applicable law. Such irrevocable proxy shall be valid until the termination of this Agreement pursuant to Section 7 herein.

Section 5. Adjustments Upon Share Issuances, Changes in Capitalization. In the event of any change in Earthstone Common Stock or in the number of outstanding shares of Earthstone Common Stock by reason of a stock dividend, subdivision, reclassification, recapitalization, split, combination, exchange of shares or other similar event or transaction or any other change in the corporate or capital structure of Earthstone (including, without limitation, the declaration or payment of an extraordinary dividend of cash, securities or other property), and consequently the number of Shares changes or is otherwise adjusted, this Agreement and the obligations hereunder shall attach to any additional shares of Earthstone Common Stock, Stockholder Rights or other securities or rights of Earthstone issued to or acquired by Stockholder.

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Section 6. Further Assurances. Stockholder will, from time to time, execute and deliver, or cause to be executed and delivered, such additional or further transfers, assignments, endorsements, consents and other instruments as the Company may reasonably request for the purpose of effectively carrying out the transactions contemplated by this Agreement and to vest the power to vote Stockholder’s Shares as contemplated by Section 3 herein.

Section 7. Termination. This Agreement, and all rights and obligations of the parties hereunder, shall terminate upon the earlier of (a) the Closing Date and (b)(i) with respect to the obligations to vote on the Exchange Agreement and the Contribution Agreement, the date upon which the Exchange Agreement is terminated pursuant to Section 7.1 thereof, including, any termination in connection with the Earthstone Board’s decision to accept a Superior Proposal and (ii) with respect to the obligation to vote on the Contribution Agreement, the date on which the Contribution Agreement is terminated in accordance with its terms. Notwithstanding the foregoing, Sections 7, 8 and 9 hereof shall survive any termination of this Agreement.

Section 8. Action in Stockholder Capacity Only. No person executing this Agreement who is or becomes during the term hereof a director or officer of Earthstone makes any agreement or understanding herein in his or her capacity as such director or officer. Stockholder signs solely in his capacity as the record holder and beneficial owner of, or the trustee of a trust whose beneficiaries are the beneficial owners of, Stockholder’s Shares and nothing herein shall prohibit, limit, restrict or affect any actions taken by or fiduciary duties of Stockholder or any of his affiliates in its or their capacity as an officer or director of Earthstone to the extent permitted by the Exchange Agreement and applicable law.

Section 9. Miscellaneous.

(a) Assignment. Neither this Agreement nor any of the rights, interests or obligations hereunder shall be assigned by any of the parties without the prior written consent of the other parties. Subject to the preceding sentence, this Agreement will be binding upon, inure to the benefit of and be enforceable by the parties and their respective successors and assigns. This Agreement shall also inure to the benefit of and be enforceable by Flatonia, who shall be deemed a third party beneficiary hereof. Stockholder agrees that this Agreement and the obligations of Stockholder hereunder shall attach to Stockholder’s Shares and shall be binding upon any person or entity to which legal or beneficial ownership of such Shares shall pass, whether by operation of law or otherwise, including without limitation Stockholder’s successors.

(b) Expenses. All costs and expenses incurred in connection with this Agreement and the transactions contemplated thereby shall be paid by the party incurring such expenses.

(c) Amendments. This Agreement may not be amended except by an instrument in writing signed by each of the parties hereto and in compliance with applicable law.

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(d) Notice. All notices and other communications hereunder shall be in writing and shall be deemed duly given if delivered personally, mailed by registered or certified mail (return receipt requested), overnight delivery or sent via facsimile to the parties at the following addresses (or at such other address for a party as shall be specified by like notice):

(e) Interpretation. The headings contained in this Agreement are for reference purposes only and shall not affect in any way the meaning or interpretation of this Agreement. In this Agreement, unless a contrary intention appears, (i) the words “herein,” “hereof” and “hereunder” and other words of similar import refer to this Agreement as a whole and not to any particular Section or other subdivision and (ii) reference to any Section means such Section hereof. No provision of this Agreement shall be interpreted or construed against any party hereto solely because such party or its legal representative drafted such provision.

(f) Counterparts. This Agreement may be executed in two or more counterparts, each of which shall be deemed an original but all of which shall be considered one and the same agreement. Delivery of an executed counterpart signature page of this Agreement by facsimile is as effective as executing and delivering this Agreement in the presence of the other parties.

(g) Entire Agreement. This Agreement constitutes the entire agreement of the parties and supersedes all prior agreements and undertakings, both written and oral, between the parties, or any of them, with respect to the subject matter hereof, and except as otherwise expressly provided herein, is not intended to confer upon any other Person any rights or remedies hereunder.

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(h) Governing Law; Consent to Jurisdiction; Waiver of Trial by Jury. This Agreement shall be governed by, and construed in accordance with, the laws of the State of Delaware, without regard to laws that may be applicable under conflicts of laws principles. Each of the parties hereto irrevocably and unconditionally (i) agrees that any suit, action or other legal proceeding arising out of or relating to this Agreement shall be brought in the state courts of the State of Delaware (or, if such courts do not have jurisdiction or do not accept jurisdiction, in the United States District Court located in the State of Delaware), (ii) consents to the jurisdiction of any such court in any such suit, action or proceeding, and (iii) waives any objection that such party may have to the laying of venue of any such suit, action or proceeding in any such court. Each of the parties hereto agrees that a final judgment in any such action or proceeding shall be conclusive and may be enforced in other jurisdictions by suit on the judgment or in any other manner provided by law. Each party to this Agreement irrevocably consents to service of process in the manner provided for notices in Section 9(d). Nothing in this Agreement will affect the right of any party to this Agreement to serve process in any other manner permitted by law.

EACH PARTY ACKNOWLEDGES AND AGREES THAT ANY CONTROVERSY WHICH MAY ARISE UNDER THIS AGREEMENT IS LIKELY TO INVOLVE COMPLICATED AND DIFFICULT ISSUES, AND THEREFORE IT HEREBY IRREVOCABLY AND UNCONDITIONALLY WAIVES ANY RIGHT IT MAY HAVE TO A TRIAL BY JURY IN RESPECT OF ANY LITIGATION DIRECTLY OR INDIRECTLY ARISING OUT OF OR RELATING TO THIS AGREEMENT AND ANY OF THE AGREEMENTS DELIVERED IN CONNECTION HEREWITH OR THE TRANSACTIONS CONTEMPLATED HEREBY OR THEREBY. EACH PARTY CERTIFIES AND ACKNOWLEDGES THAT (A) NO REPRESENTATIVE, AGENT OR ATTORNEY OF ANY OTHER PARTY HAS REPRESENTED, EXPRESSLY OR OTHERWISE, THAT SUCH OTHER PARTY WOULD NOT, IN THE EVENT OF LITIGATION, SEEK TO ENFORCE EITHER OF SUCH WAIVERS, (B) IT UNDERSTANDS AND HAS CONSIDERED THE IMPLICATIONS OF SUCH WAIVERS, (C) IT MAKES SUCH WAIVERS VOLUNTARILY, AND (D) IT HAS BEEN INDUCED TO ENTER INTO THIS AGREEMENT BY, AMONG OTHER THINGS, THE MUTUAL WAIVERS AND CERTIFICATIONS IN THIS SECTION 9(h).

(i) Specific Performance. The parties to this Agreement agree that irreparable damage would occur in the event that any provision of this Agreement was not performed in accordance with the terms of this Agreement and that the Company shall be entitled to specific performance of the terms of this Agreement in addition to any other remedy at law or equity.

(j) Severability. If any term, provision, covenant or restriction of this Agreement is held by a court of competent jurisdiction or other authority to be invalid, void, unenforceable or against its regulatory policy, the remainder of the terms, provisions, covenants and restrictions of this Agreement shall remain in full force and effect and shall in no way be affected, impaired or invalidated.

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(k) Non-Recourse. No past, present or future employee, partner, agent, attorney, representative or affiliate of Stockholder hereto or of any of their respective affiliates shall have any liability (whether in contract or in tort) for any obligations or liabilities of such party arising under, in connection with or related to this Agreement or for any claim based on, in respect of, or by reason of, the transactions contemplated hereby; provided, however, that nothing in this Section 9(k) shall limit any liability of Stockholder hereto for his breaches of the terms and conditions of this Agreement.

(l) Waiver. No failure or delay by any party in exercising any right, power or privilege hereunder shall operate as a waiver thereof nor shall any single or partial exercise thereof preclude any other or further exercise thereof or the exercise of any other right, power or privilege. The rights and remedies herein provided shall be cumulative and not exclusive of any rights or remedies provided by applicable law.

[Remainder of Page Intentionally Left Blank; Signature Page Follows]

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IN WITNESS WHEREOF, the Company has caused this Agreement to be signed by its officer thereunto duly authorized and Stockholder has signed this Agreement, all as of the date first written above.

VOTING AGREEMENT

STOCKHOLDER SIGNATURE PAGE

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IN WITNESS WHEREOF, the Company has caused this Agreement to be signed by its officer thereunto duly authorized and Stockholder has signed this Agreement, all as of the date first written above.

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SCHEDULE A

OWNERSHIP OF SHARES

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