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|        | Occidental Energy Marketing, Inc.A subsidiary of Occidental Petroleum Corporation | 5 Greenway Plaza, Suite 110, Houston, Texas 77046-0521P. O. Box 27570, Houston, Texas 77227-7570Phone 713.215.7000 |
|--------|-----------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------|
|   |                                                                              |

|   |   |                                    |   |         |
|--------|--------|-----------------------------------------|--------|--------------|
| TO:    |   | Pioneer Natural Resources USA, Inc.     |   |         |
|   |   | Attn: Contract Management Services      |   |         |
|   |   | Fax: (972) 969-3574                     |   |         |
|   |   | Trader: Deb Stewart                     |   |         |
|   |   |                                    |   |         |
| FROM:  |   | Occidental Energy Marketing, Inc.       |   |         |
|   |   | Trader: Mark Hafner                     |   |         |
|   |   |                                    |   |         |
| RE:    |   | Occidental Contract # 0809-PNR-134117-P |   | Amendment #1 |

|       | This Amendment Number 1 to the Crude Oil Contract between Occidental Energy Marketing, Inc. ("OEMI") and Pioneer Natural Resources USA, Inc. ("Counterparty") dated September, 2008 (the "Contract") is entered into as of January 13, 2011. |
|------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
|       |                                                                                                                                                                                                                                         |
|       | For good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged and agreed, the Parties agree that the Contract is hereby amended effective January 1, 2011 as set forth below.                            |
|       |                                                                                                                                                                                                                                         |
|       | Change the transporter on the Parks 5 & 13*lease to Centurion PL on the contract and Exhibit "A".                                                                                                                                        |
|       |                                                                                                                                                                                                                                         |
|       | All other terms of the agreement are unchanged.                                                                                                                                                                                              |
|       |                                                                                                                                                                                                                                         |
|       | Agreed to and approved by:                                                                                                                                                                                                                   |
|       | OEMI                                                                                                                                                                                                                                         |
|       |                                                                                                                                                                                                                                         |
|       |  /s/ Mark Hafner                                                                                                                                                                                                                        |   |
|       | Mark Hafner                                                                                                                                                                                                                                  |
|       | Director, Crude Oil Acquisitions                                                                                                                                                                                                             |
|       |                                                                                                                                                                                                                                         |
|       | Agreed to and approved by:                                                                                                                                                                                                                   |
|       | Pioneer Natural Resources USA, Inc.                                                                                                                                                                                                          |
|       |                                                                                                                                                                                                                                         |
|       |  /s/ Hershal K. Wolfe                                                                                                                                                                                                                   |   |
|       |                                                                                                                                                                                                                                         |   |
|       | Hershal K. Wolfe                                                                                                                                                                                                                        |   |
|       | Vice President Marketing                                                                                                                                                                                                                     |   |
|       |                                                                                                                                                                                                                                         |   |
| 01/13/2011 |

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|             |   |    |   |                      |   |              |   |                 |   |         |   |    |   |   |   |               |   |   |   |                 |   |     |   |               |
|------------------|--------|---------|--------|---------------------------|--------|-------------------|--------|----------------------|--------|--------------|--------|---------|--------|--------|--------|--------------------|--------|--------|--------|----------------------|--------|----------|--------|--------------------|
| INTERFACE        |   | PRODUCT |   | OPERATOR                  |   | LEASE NAME        |   | LEASE EFFECTIVE DATE |   | CONTROLLED   |   | COUNTY  |   | STATE  |   | TRANSPORTER        |   | DELTA  |   | DELTA EFFECTIVE DATE |   | CONTRACT |   | PRICE INDEX        |
| 742087310000PNTS |   | WTl     |   | Pioneer Natural Resources |   | Parks 17 & 25 |   | 9/1/2008             |   | 100.00000000 |   | MIDLAND |   | TX     |   | OET Trucks         |   | $0.85  |   | 9/1/2008             |   | 134117   |   | XP - Midland Sweet |
| 742087300000PNTS |   | WTI     |   | Pioneer Natural Resources |   | Parks 5 & 13  |   | 9/1/2008             |   | 100.00000000 |   | MIDLAND |   | TX     |   | Centurion Pipeline |   | $0.85  |   | 1/1/2011             |   | 134117   |   | XP - Midland Sweet |

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