AMENDMENT TO PURCHASE AND SALE AGREEMENT

Exhibit 10.1

AMENDMENT TO PURCHASE AND SALE AGREEMENT

THIS AMENDMENT TO PURCHASE AND SALE AGREEMENT (the "Amendment") is made as of the 31^st day of January, 2008, by and between APACHE CORPORATION, a Delaware corporation (hereinafter referred to as "Seller") and VANGUARD PERMIAN, LLC, a Delaware limited liability company (hereinafter referred to as "Purchaser").

WHEREAS Seller and Purchaser entered into a certain Purchase and Sale Agreement dated as of the 21^st day of December, 2007 (the "PSA"), and

WHEREAS Seller and Purchaser wish to amend said PSA as set out herein;

NOW THEREFORE, in consideration of the premises hereto and the covenants and agreements hereinafter set forth and contained, the parties hereto covenant and agree as follows:

1. The PSA is hereby amended effective as of the time the PSA was executed and delivered by deleting Schedules "A", "B", "C" and "D" attached thereto and substituting in their place, each of the new Schedules. Schedules "A", "B", "C" and "D" attached hereto.

2. Seller and Purchaser hereby ratify and confirm the PSA which shall continue in full force and effect in accordance with its terms, unamended, except as specifically set out herein.

3. All capitalized terms which are not defined herein shall have the meaning ascribed in the PSA.

This Amendment shall, in all respects, be subject to, interpreted, construed and enforced in accordance with and under the laws of the State of Texas and shall, in all respects, be treated as a contract made in the State of Texas

IN WITNESS WHEREOF, the parties hereto have executed this Amendment as of the date first above written.

SCHEDULE "A"

To Amendment to Purchase and Sale Agreement
Dated January 31, 2008
Between APACHE CORPORATION, as Seller
and VANGUARD PERMIAN, LLC, as Purchaser

LEASES

SCHEDULE A
Page 1 of 8

SCHEDULE "A"

To Amendment to Purchase and Sale Agreement
Dated January 31, 2008
Between APACHE CORPORATION, as Seller
and VANGUARD PERMIAN, LLC, as Purchaser

LEASES

SCHEDULE A
Page 2 of 8

SCHEDULE "A"

To Amendment to Purchase and Sale Agreement
Dated January 31, 2008
Between APACHE CORPORATION, as Seller
and VANGUARD PERMIAN, LLC, as Purchaser

LEASES

SCHEDULE A
Page 3 of 8

SCHEDULE "A"

To Amendment to Purchase and Sale Agreement
Dated January 31, 2008
Between APACHE CORPORATION, as Seller
and VANGUARD PERMIAN, LLC, as Purchaser

LEASES

SCHEDULE A
Page 4 of 8

SCHEDULE "A"

To Amendment to Purchase and Sale Agreement
Dated January 31, 2008
Between APACHE CORPORATION, as Seller
and VANGUARD PERMIAN, LLC, as Purchaser

LEASES

SCHEDULE A
Page 5 of 8

SCHEDULE "A"

To Amendment to Purchase and Sale Agreement
Dated January 31, 2008
Between APACHE CORPORATION, as Seller
and VANGUARD PERMIAN, LLC, as Purchaser

LEASES

SCHEDULE A
Page 6 of 8

SCHEDULE "A"

To Amendment to Purchase and Sale Agreement
Dated January 31, 2008
Between APACHE CORPORATION, as Seller
and VANGUARD PERMIAN, LLC, as Purchaser

LEASES

SCHEDULE A
Page 7 of 8

SCHEDULE "A"

To Amendment to Purchase and Sale Agreement
Dated January 31, 2008
Between APACHE CORPORATION, as Seller
and VANGUARD PERMIAN, LLC, as Purchaser

LEASES

SCHEDULE A
Page 8 of 8

SCHEDULE "B"

To Amendment To Purchase and Sale Agreement
Dated January 31, 2008
Between APACHE CORPORATION, as Seller
and VANGUARD PERMIAN, LLC, as Purchaser

MINERAL RIGHTS

SCHEDULE "B"

To Amendment To Purchase and Sale Agreement
Dated January 31, 2008
Between APACHE CORPORATION, as Seller
and VANGUARD PERMIAN, LLC, as Purchaser

MINERAL RIGHTS

As corrected, as to the lands described herein, by that certain Act of Correction dated March 31, 1992, between Amoco Production Company and MW Petroleum Corporation and recorded in Book 568, page 680 of the records of Gaines County, Texas

SCHEDULE B
Page 2 of 2

SCHEDULE "C"

To Amendment to Purchase and Sale Agreement
Dated January 31, 2008
Between APACHE CORPORATION, as Seller
and VANGUARD PERMIAN, LLC, as Purchaser

REAL PROPERTY

SCHEDULE C
Page 1 of 1

SCHEDULE "D"

To Amendment to Purchase and Sale Agreement
Dated January 31, 2008
Between APACHE CORPORATION, as Seller
and VANGUARD PERMIAN, LLC, as Purchaser

EASEMENTS

SCHEDULE D
Page 1 of 3

SCHEDULE "D"

To Amendment to Purchase and Sale Agreement
Dated January 31, 2008
Between APACHE CORPORATION, as Seller
and VANGUARD PERMIAN, LLC, as Purchaser

EASEMENTS

SCHEDULE D
Page 2 of 3

SCHEDULE "D"

To Amendment to Purchase and Sale Agreement
Dated January 31, 2008
Between APACHE CORPORATION, as Seller
and VANGUARD PERMIAN, LLC, as Purchaser

EASEMENTS

SCHEDULE D
Page 3 of 3