ASSIGNMENT AND ASSUMPTION AGREEMENT

Exhibit 2.2

ASSIGNMENT AND ASSUMPTION AGREEMENT

THIS ASSIGNMENT AND ASSUMPTION AGREEMENT (this “Agreement”) is entered into this 9^th day of June, 2013 between Atlas Resource Partners, L.P., a Delaware limited partnership (“Assignor”), Atlas Energy, L.P., a Delaware limited partnership (“ATLS”) and, upon its formation, ATLS Production Company, LLC, a Delaware limited liability company (“APC”).

WHEREAS, Assignor is a party to the Purchase and Sale Agreement (the “Purchase Agreement”), dated as of June 9, 2013, among EP Energy E&P Company, L.P., a Delaware limited partnership and EPE Nominee Corp., a Delaware corporation (together, “Seller”) and Assignor;

WHEREAS, Section 13.4 of the Purchase Agreement provides that Assignor may assign its right and obligation to acquire the Assets and Assumed Liabilities (in each case as defined in the Purchase Agreement) relating to the Arkoma basin, and its related obligations under the Purchase Agreement, to ATLS or a subsidiary thereof;

WHEREAS, at or prior to the Closing, as set forth in the Purchase Agreement:

WHEREAS, if Closing shall occur, effective from and after the Closing Date:

WHEREAS, Assignee has reviewed the Purchase Agreement and understands the rights and obligations of Assignor, as Buyer, and Seller provided thereunder;

WHEREAS, Assignor desires to assign to Assignee:

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NOW, THEREFORE, in consideration of the promises and the mutual agreements and covenants contained herein and for other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the parties hereto hereby agree as follows:

(a) the Arkoma Rights; and

(b) the Arkoma Obligations

In the event the Agreement is terminated for any reason whatsoever, the rights and obligations set forth in this Section 2 shall terminate without further action by the parties hereto.

(a) the Arkoma Purchase Price; plus

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(b) for upward or downward purchase price adjustments pursuant to Section 2.5 of the Purchase Agreement arising specifically with reference to any Arkoma Assets, the full amount of such purchase price adjustments; plus

(c) for upward or downward purchase price adjustments pursuant to Section 2.5 of the Purchase Agreement arising specifically with reference to any specific Assets other than the Arkoma Assets, zero; plus

(d) for upward or downward purchase price adjustments pursuant to Section 2.5 of the Purchase Agreement that cannot be allocated between the Arkoma Assets and other Assets, or that arise generally in connection with the ownership or operation of the Assets, 8.31731% of such purchase price adjustments.

(a) for indemnification and other payments pursuant to Section 4.2 of the Purchase Agreement arising specifically with reference to any Arkoma Assets, the full amount of such payment;

(b) for indemnification and other payments pursuant to Section 4.2 of the Purchase Agreement arising specifically with reference to any specific Assets other than the Arkoma Assets, zero;

(c) for indemnification and other payments pursuant to Section 4.2 of the Purchase Agreement that cannot be allocated between the Arkoma Assets and other Assets, or that rise generally in connection with the ownership or operation of the Assets, 8.31731% of such payment.

(a) for indemnification and other payments pursuant to Section 4.3 of the Purchase Agreement arising specifically with reference to any Arkoma Assets, the full amount of such payment;

(b) for indemnification and other payments pursuant to Section 4.3 of the Purchase Agreement arising specifically with reference to any specific Assets other than the Arkoma Assets, zero;

(c) for indemnification and other payments pursuant to Section 4.3 of the Purchase Agreement that cannot be allocated between the Arkoma Assets and other Assets, or that arise generally in connection with the ownership or operation of the Assets, 8.31731% of such payment.

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(a) to the extent necessary or advisable, or upon the request of either party hereto, the parties shall agree in good faith upon the allocation of other rights, obligations and responsibilities under the Purchase Agreement not addressed in this Agreement and shall enter into such additional agreements or arrangements as may be necessary or appropriate to, carry out or give effect to the intent of this Agreement or the Purchase Agreement, or to clarify the relationship of this Agreement to the particular terms of the Purchase Agreement, including as to operating services or transition services, provided that the failure to reach any such agreement or to enter into any such agreements or arrangements shall not affect, limit or reduce Assignee’s obligations to perform any of its obligations hereunder, to purchase and acquire the Arkoma Rights and fully assume and perform the Arkoma Obligations from and after the Closing, or to consummate the transactions contemplated by the Purchase Agreement.

(b) upon the request of any party hereto, the other party hereto shall, without further consideration, execute and deliver, or cause to be executed and delivered, such further instruments, and shall take, or cause to be taken, such further or other actions as the other party hereto may reasonably request to confirm or otherwise carry out or give effect to the intent of this Agreement or the Purchase Agreement.

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[Signature Pages Follow]

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IN WITNESS WHEREOF, the parties have caused this Agreement to be executed by their respective authorized officers on the date written above.

[Signature Page to Assignment and Assumption]