[ENCANA LETTERHEAD]

Exhibit 10(xxv)

[ENCANA LETTERHEAD]

October 21, 2014

Nucor Energy Holdings Inc.

1915 Rexford Road

Charlotte, North Carolina 28211

Attn: Chief Financial Officer

Attn: Mr. Brad True

Dear Brad:

Pursuant to our recent discussions, Encana and Nucor (collectively, the “Parties”) have agreed to amend the Agreement to revise the drilling schedule for 2015 and provide for an optional Head’s Up Well drilling program in calendar year 2016.

In light of the foregoing, and in consideration of the mutual covenants and agreements herein, and for other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the Parties agree as follows:

AGREEMENT

During calendar year 2015, the Parties agree that drilling operations will be limited to [***] total Carry Wells on the [***] of the Big Jimmy Unit, which comprises a portion of the Property. For the calendar year 2016 and thereafter, Encana shall spud a minimum of [***] and a maximum of [***] Carry Wells in each calendar year until such time as the Carry Well Threshold has been met.

(i)     On or before September 1, 2015, Encana will offer to Nucor in writing (“Optional HUW Program Notice”) the opportunity to participate in an optional Head’s Up Well program (“Optional HUW Program”)

[***] This confidential information has been omitted and filed separately with the Securities and Exchange Commission pursuant to a request for confidential treatment.

whereby [***] of the drilling rigs that would otherwise be dedicated to drilling Carry Wells in calendar year 2016 would instead be dedicated to drilling only Head’s Up Wells in calendar year 2016. The location of the Head’s Up Wells to be drilled pursuant to the Optional HUW Program would be determined in a manner consistent with Section 2.1B. Nucor shall have fifteen (15) days from receipt of the Optional HUW Program Notice to make a one-time election in writing (“Nucor Election”) to participate in the Optional HUW Program. If Nucor elects to participate in the Optional HUW Program, Encana shall have fifteen (15) days from receipt of the Nucor Election to advise Nucor in writing whether Encana elects to participate in the Optional HUW Program (“Encana Election”). If Encana elects not to participate in the Optional HUW Program, Nucor shall have fifteen (15) days after receipt of the Encana Election to reaffirm the Nucor Election in writing to Encana. Each Party shall be deemed to have elected not to participate in the Optional HUW Program if it fails to timely provide its Election or affirmation of its Election, as applicable, as required by this Section 2.4G(i). If a Party elects to participate in the Optional HUW Program, it has elected to participate in the entirety of the Program and may not decline to participate in any Head’s Up Well drilled pursuant to the Optional HUW Program. If both Parties decline to participate in the Optional HUW Program, Encana may, in its sole discretion, release or redeploy the designated Head’s Up Well drilling rig to non-Nucor drilling activity. The Parties expressly agree that Encana may simultaneously drill Head’s Up Wells pursuant to the Optional HUW Program and Carry Wells. The Parties further agree that any Head’s Up Wells drilled pursuant to the Optional HUW Program shall (1) count toward satisfaction of the minimum number of wells required to be drilled pursuant to Section 2.2A and (2) be excluded from the number of Carry Wells used to determine the HUW Restriction for calendar year 2017.

(ii)     So long as both Parties elect to participate, each Head’s Up Well drilled pursuant to the Optional HUW Program shall be counted as one well toward the Well Limit. If only Nucor participates, each Head’s Up Well drilled pursuant to the Optional HUW Program shall be counted as two wells toward the Well Limit.

(iii)     If both Parties elect to participate in the Optional HUW Program, each Party shall bear fifty percent (50%) of the costs of the Program. If Encana elects not to participate in an Optional HUW Program and Nucor elects to proceed with such Optional HUW Program, the Parties shall proceed in accordance with Section 4.2.

Notwithstanding anything to the contrary set forth herein, in the event any changes in Applicable Law or interpretations thereof by any Governmental Authorities have the effect of making the form of wellbore assignment attached hereto as Exhibit C insufficient to grant to Nucor rights to Nucor Wells (whether existing or subsequently completed), oil

[***] This confidential information has been omitted and filed separately with the Securities and Exchange Commission pursuant to a request for confidential treatment.

and gas production therefrom and equipment related thereto, in each case as contemplated in this Agreement or in the New Operating Agreement, the Parties agree to amend any existing Wellbore Assignments as well as the form of wellbore assignment to the extent necessary to preserve and maintain Nucor’s rights in the foregoing as contemplated in this Agreement or in the New Operating Agreement.

Sincerely,

Encana Oil & Gas (USA) Inc.

by its authorized agent,

Encana Services Company Ltd.

/s/ Jeffrey S. Balmer

Jeffrey S. Balmer

Vice President and General Manager

Western Operations

EXHIBIT C

Attached to and made a part of the BJU Carry & Earning Agreement executed October 31, 2012 but effective

November 1, 2012 by and between Encana Oil & Gas (USA) Inc. and Nucor Energy Holdings Inc.

Form of Wellbore Assignment and Conveyance

THAT Encana Oil & Gas (USA) Inc., whose address is 370 17^th Street, Suite 1700, Denver, CO 80202 (hereinafter referred to as “Assignor”) for good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged and confessed, does hereby GRANT, BARGAIN, SELL, TRANSFER, ASSIGN, AND CONVEY unto Nucor Energy Holdings Inc., whose address is 1915 Rexford Road, Charlotte, NC 28211 (hereinafter referred to as “Assignee”) an undivided fifty percent (50.00%) of Assignor’s right, title, interest, and estate in and to the following, subject to the limitations below (collectively, the “Assigned Interests”):

Assignor and Assignee further agree as follows:

TO HAVE AND TO HOLD the Assigned Interests unto Assignee and its successors and assigns, subject to all the express and implied covenants and obligations of the Leases and this Assignment.

EXECUTED this ___ day of ____2014, but effective as of the date of first production for each Well as set forth on Exhibit A.

ACKNOWLEDGEMENTS

BEFORE ME, the undersigned authority, on this day personally appeared Constance D. Heath, Director, Land Negotiation, Western Operations for Encana Services Company Ltd, authorized agent for ENCANA OIL & GAS (USA) INC. known to me to be the person whose name is subscribed to the foregoing instrument, and acknowledged to me that she executed the same for the purposes and consideration therein expressed and in the capacity therein stated.

GIVEN UNDER MY HAND AND OFFICIAL SEAL OF OFFICE on this ____ day of __________, 2014.

BEFORE ME, the undersigned authority, on this day personally appeared, Bradford G. True, Vice President for NUCOR ENERGY HOLDINGS INC. known to me to be the person whose name is subscribed to the foregoing instrument, and acknowledged to me that he executed the same for the purposes and consideration therein expressed and in the capacity therein stated.

GIVEN UNDER MY HAND AND OFFICIAL SEAL OF OFFICE on this ____ day of __________, 2014.

Recording Requested and when Recorded