| Acock/Anaqua Operating Co., LP |
003599 |
| Ascendance Energy Partners, LLC |
033892 |
| Beehive Operating, LLC |
061750 |
| Bettis, Boyle & Stovall |
068360 |
| Bluestone Natural Res. II, LLC |
076861 |
| BNR Operating, LLC |
077577 |
| Buffco Production Inc. |
106406 |
| Bustamante Oil Company |
112685 |
| BXP Operating, LLC |
042191 |
| Chesapeake Operating, L.L.C. |
147699 |
| Chevron U. S. A. Inc. |
148113 |
| Columbus Energy, LLC |
169313 |
| Comstock Oil & Gas, LP |
170040 |
| Conocophillips Company |
172232 |
| Continental Operating Co. |
173749 |
| Conway Energy Oper Services Inc. |
174017 |
| Cowrie Energy LLC |
183056 |
| Crimson Exploration Oper., Inc. |
190005 |
| Dale Operating Company |
197624 |
| Devon Energy Production Co, L.P. |
216378 |
| Dynamic Production, Inc. |
237926 |
| Eagle Energy Resources, LLC |
238722 |
| Eagle Oil & Gas Co. |
238634 |
| Elliott Oil & Gas Operating Co. |
247836 |
| Encina Resources, LLC |
251741 |
| Endeavor Natural Gas, LP |
251729 |
| Enerquest Operating L.L.C. |
252058 |
| EOG Resources, Inc. |
253162 |
| Ep Energy E&P Company, L.P. |
253385 |
| Escudo Oil & Gas, LLC |
254264 |
| Finaly Resources LLC |
268323 |
| Forza Operating, LLC |
278837 |
| Hilcorp Energy Company |
386310 |
| Hughes, Dan A. Company, L.P. |
411736 |
| Kaiser-Francis Oil Company |
450175 |
| Killam Oil Co., LTD. |
460054 |
| Kovar Operating, LLC |
448984 |
| Laredo Energy Operating, LLC |
486517 |
| Magnum Producing, LP |
521516 |
| Marwell Petroleum LTD Partnrship |
531085 |
| Merit Energy Company |
561136 |
| Mortimer Production Company |
589954 |
| Outline Oil Company LLC |
628480 |
| Oxy USA Inc. |
630591 |
| Pioneer Natural Res. USA, Inc. |
665748 |
| Pressly Oil Interest, Inc. |
676076 |
| Prime Operating Company |
677770 |
| Proline Energy Resources Inc |
681327 |
| Raker Resources LLC |
689172 |
| Remora Operating, LLC |
701613 |
| Ricochet Energy, Inc. |
710549 |
| Rlu Operating, LLC |
714217 |
| Rockdale Energy, LLC |
722895 |
| Rosetta Resources Operating LP |
728883 |
| Safari Production Company, Inc. |
743197 |
| Salt Creek Production, Inc. |
744277 |
| Sanchez Oil & Gas Corporation |
747012 |
| Sandel Operating Company |
747534 |
| Shell Western E&P |
774719 |
| Shidler, Mark L., Inc. |
776590 |
| Silver Fox Oil & Gas LLP |
781914 |
| Smith Operating And MGMT Co. |
794541 |
| Smith Production Inc. |
789662 |
| Stephens & Johnson Operating Co. |
817555 |
| Sue-Ann Operating, L.C. |
828352 |
| Unit Petroleum Company |
877099 |
| Vaquero Operating |
882776 |
| Vast Oil TX Operating LLC |
883803 |
| Vision Oil And Gas LLC |
886198 |
| Wagner Oil Company |
891175 |
| White Oak Operating Company LLC |
916954 |
| XTO Energy Inc. |
945936 |