Exhibit 10.9

Ladies and Gentlemen,

Reference is made to (i) the confirmation dated February 29, 2012 confirming the terms and conditions of those certain base warrants issued by Stone Energy Corporation (“Counterparty”) to Barclays Capital PLC (“Dealer”), through its agent Barclays Capital Inc. (the “Agent”), as of the “Trade Date” specified therein (as amended and supplemented from time to time, the “Base Warrant Confirmation”) and (ii) the confirmation dated March 2, 2012 confirming the terms and conditions of those certain additional warrants issued by Counterparty to Dealer as of the “Trade Date” specified therein (as amended and supplemented from time to time, the “Additional Warrant Confirmation”, and each of the Base Warrant Confirmation and the Additional Warrant Confirmation a “Confirmation” and together the “Confirmations”). Capitalized terms used but not otherwise defined herein shall have the meanings given to such terms in the Confirmations.

In order to clarify the parties’ intent as of the date of each Confirmation, each of Dealer and Counterparty, intending to be legally bound, hereby acknowledges and agrees that:

1. Paragraph 5(j)(i) of each Confirmation is hereby amended by inserting the words “of a similar size” (x) after the word “procedures” in the third line thereof and (y) after the word “agreements” in the sixteenth line thereof.

2. Paragraph 5(j)(ii) of each Confirmation is hereby amended by inserting the words “of a similar size” after the word “agreements” in the twelfth line thereof.

3. The following is added to each Confirmation as a new paragraph 5(v)(xi) thereto:

“(xi) In the event that (i) an Early Termination Date occurs or is designated with respect to the Transaction as a result of a Termination Event or an Event of Default (other than an Event of Default arising under Section 5(a)(ii) or 5(a)(iv) of the Agreement) and, as a result, Dealer owes to Counterparty an amount calculated under Section 6(e) of the Agreement, or (ii) Dealer owes to Counterparty, pursuant to Section 12.7 or Section 12.9 of the Equity Definitions, an amount calculated under Section 12.8 of the Equity Definitions, such amount shall be deemed to be zero.”

4. Each party hereby makes to the other party on the date hereof each of the representations contained in Sections 3(a) and 3(b) of the Agreement specified in each Confirmation.

5. Each of Counterparty and Dealer hereby confirms that each Confirmation, as amended hereby, and the terms of each Transaction specified therein shall continue in full force and effect. All references to the “Confirmation” and the “Transaction” in each Confirmation or any document related thereto shall for all purposes constitute references to the Base Warrant Confirmation or the Additional Warrant Confirmation, as the case may be, as amended hereby.

6. This letter agreement and all matters arising in connection with this letter agreement shall be governed by and construed in accordance with the law of the State of New York (without reference to its choice of law doctrine other than Title 14 of the New York General Obligations Law).

7. EACH PARTY IRREVOCABLY WAIVES, TO THE FULLEST EXTENT PERMITTED BY APPLICABLE LAW, ANY RIGHT IT MAY HAVE TO A TRIAL BY JURY IN RESPECT OF ANY SUIT, ACTION OR PROCEEDING RELATING TO THE TRANSACTIONS. EACH PARTY (I) CERTIFIES THAT NO REPRESENTATIVE, AGENT OR ATTORNEY OF THE OTHER PARTY HAS REPRESENTED, EXPRESSLY OR OTHERWISE, THAT SUCH OTHER PARTY WOULD NOT, IN THE EVENT OF SUCH A SUIT, ACTION OR PROCEEDING, SEEK TO ENFORCE THE FOREGOING WAIVER AND (II) ACKNOWLEDGES THAT IT AND THE OTHER PARTY HAVE BEEN INDUCED TO ENTER INTO THE TRANSACTIONS, AS APPLICABLE, BY, AMONG OTHER THINGS, THE MUTUAL WAIVERS AND CERTIFICATIONS PROVIDED HEREIN.

8. With respect to any suit, action or proceedings relating to any dispute arising out of or in connection with this letter agreement (“Proceedings”), each party irrevocably (i) submits to the non-exclusive jurisdiction of the courts of the State of New York and the United States District Court located in the Borough of Manhattan in New York City; (ii) waives any objection which it may have at any time to the laying of venue of any Proceedings brought in any such court, waives any claim that such Proceedings have been brought in an inconvenient forum and further waives the right to object, with respect to such Proceedings, that such court does not have any jurisdiction over such party; and (iii) agrees, to the extent permitted by applicable law, that the bringing of Proceedings in any one or more jurisdictions will not preclude the bringing of Proceedings in any other jurisdiction.

9. No amendment, modification or waiver in respect of this letter agreement will be effective unless in writing (including a writing evidence by a facsimile transmission) and executed by each of the parties. This letter agreement (and any amendment, modification and waiver in respect of it) may be executed in several counterparts (including by facsimile transmission), each of which shall be deemed an original but all of which together shall constitute one and the same instrument.

10. Each party acknowledges to and agrees with the other party hereto and to and with Agent that (i) Agent is acting as agent for Dealer under each Confirmation, as amended hereby, and the terms of each Transaction specified therein pursuant to instructions from such party, (ii) Agent is not a principal or party to such Transactions, and may transfer its rights and obligations with respect to such Transactions, (iii) Agent shall have no responsibility, obligation or liability, by way of issuance, guaranty, endorsement or otherwise in any manner with respect to the performance of either party under such Transactions, (iv) Dealer and Agent have not given, and Counterparty is not relying (for purposes of making any investment decision or otherwise) upon, any statements, opinions or representations (whether written or oral) of Dealer or Agent, other than the representations expressly set forth in each Confirmation or the Agreement specified therein, and (v) each party agrees to proceed solely against the other party, and not Agent, to collect or recover any money or securities owed to it in connection with such Transactions. Each party hereto acknowledges and agrees that Agent is an intended third party beneficiary hereunder. Counterparty acknowledges that Agent is an affiliate of Dealer. Dealer will be acting for its own account in respect of each Confirmation, as amended hereby, and the Transactions contemplated thereunder, as amended hereby.

[Signature page follows.]

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Counterparty hereby agrees to check this letter agreement and to confirm that the foregoing correctly sets forth the parties’ agreement by signing in the space provided below and returning to Dealer a facsimile of the fully-executed letter agreement to Dealer at (+1) 917-522-0458. Originals shall be provided for your execution upon your request.

Very truly yours,

Accepted and confirmed as of the date first written above: