Pioneer Acquires 2 Deepwater Blocks Offshore West Africa

Pioneer Natural Resources has agreed to acquire from ROC Oil a 20% interest in Blocks H15 and H16, offshore Equatorial Guinea, West Africa. Pioneer will meet ROC's obligation to pay 70% of the cost of the Bravo-1 exploration well which began drilling on June 6, 2004. Pioneer will also carry ROC's retained 15% interest through the drilling of a second well currently scheduled for 2005. Pioneer has the right to assume the roll of Technical Manager upon the completion of drilling on the Bravo-1 well provided that it meets the criteria. The transaction is subject to normal industry terms and conditions including receipt of government approval.

Other participants on the block are The Atlas Group (operator) with a 45% interest and Sasol with a 20% interest.

These offshore blocks are outside the area of common interest Pioneer has established with Kosmos Energy.