| Abraxas Petroleum Corporation |
003125 |
| Acock/Anaqua Operating Co., LP |
003599 |
| Alta Mesa Services, LP |
015721 |
| Anderson Oil LTD. |
022499 |
| Apache Corporation |
027200 |
| B D Production Co., Inc. |
040190 |
| Beehive Operating, LLC |
061750 |
| Big "6" Drilling Company |
069160 |
| B.P. Productions Inc. |
040797 |
| Britanco, L.L.C. |
093620 |
| Burke, Harry Petroleum |
108843 |
| Cabot Oil & Gas Corporation |
121700 |
| CG Technical Operating Co, LLC |
142197 |
| Chaparral Energy, L.L.C. |
144535 |
| Charro Operating, L.L.C. |
146621 |
| Cimarron Engineering, LLC |
153471 |
| Coastal Plains Exploration, LLC |
161678 |
| Comstock Oil & Gas, LP |
170040 |
| Continental Trend Resources, Inc |
173783 |
| Crest Resources, Inc. |
189901 |
| Cummins & Walker Oil Co., Inc. |
194215 |
| Dale Operating Company |
197624 |
| Decker Operating Co., L.L.C. |
209347 |
| Devon Energy Production Co, L.P. |
216378 |
| Dewbre Petroleum Corporation |
216748 |
| Double Play Oil & Gas, Inc |
224880 |
| Durango Resources Corp. |
235945 |
| Electragas, Inc. |
247628 |
| Ellsworth, H. P. O&G Properties |
249867 |
| EOG Resources, Inc. |
253162 |
| Extex Operating Company |
257062 |
| Exxon Mobil Corporation |
257128 |
| Firstrike Energy Corporation |
269066 |
| Fox, Hewitt B., Inc. |
281370 |
| Gasper Rice Resources, LTD. |
297089 |
| Geiser Operating, Inc. |
298984 |
| Great Western Drilling Company |
328780 |
| Harper Hefte, Inc. |
357865 |
| Hedrick Production Inc. |
371616 |
| Hilcorp Energy Company |
386310 |
| Howard Exploration, Inc. |
405950 |
| Hugoton Operating Company, Inc. |
412178 |
| Hunt Oil Company |
416330 |
| Hurd Enterprises, LTD. |
419886 |
| Hydrocarbon Operating, Inc. |
421166 |
| Kaler Energy Corp. |
450261 |
| Kebo Oil & Gas, Inc. |
453170 |
| Kovar Operating, LLC |
448984 |
| KRC Operating, LLC |
476900 |
| Lamar Oil & Gas, Inc. |
483925 |
| Lindenmuth & Associates, Inc. |
501202 |
| Linn Operating, LLC |
501480 |
| Magnum Engineering Company |
521539 |
| Magnum Producing, LP |
521516 |
| Marquee Corporation |
526675 |
| Marwell Petroleum LTD Partnrship |
531085 |
| Mason Resources LLC |
531416 |
| Mohican Operating, L.L.C. |
573707 |
| Morgan Enterprises, Inc. |
585750 |
| Noble Energy Inc |
611665 |
| Oxy USA Inc. |
630591 |
| Pearl, Bill H. Productions, Inc. |
647284 |
| Penn Virginia Oil & Gas, L.P. |
651780 |
| Petrogulf Corporation |
660282 |
| Petro-Hunt, L.L.C. |
660043 |
| Pintail Oil & Gas, LLC |
665697 |
| Premier Minerals, Inc. |
676033 |
| Pride Energy Company |
677050 |
| Proline Energy Resources Inc |
681327 |
| Quatro Oil And Gas, Inc. |
684588 |
| Reliance Energy, Inc. |
700995 |
| Reserve Operating Corp. |
703371 |
| Rincon Petroleum Corporation |
712336 |
| Royal Production Company, Inc. |
732075 |
| Sarita Energy Resources, LTD. |
748635 |
| Sawmill Resources, LLC |
749151 |
| Situs Oil & Gas, LLC |
785174 |
| Stephens & Johnson Operating Co. |
817555 |
| Sue-Ann Operating, L.C. |
828352 |
| Sun Exploration, Inc. |
829289 |
| Texas Petroleum Investment Co. |
847710 |
| Texron Operating, LLC |
850872 |
| Time Energy Texas LLC |
860568 |
| Urban Oil & Gas Group, LLC |
879035 |
| Ventex Operating Corp. |
884527 |
| Virtex Operating Company, Inc. |
886261 |
| Vision Oil And Gas LLC |
886198 |
| Wadi Petroleum, Inc. |
889600 |
| Wagner Oil Company |
891175 |
| Wallis Energy, Inc. |
893997 |
| Western Gulf Oil & Gas, LLC |
911925 |
| White Marlin Operating Co, LLC |
918475 |
| Whiting Oil And Gas Corporation |
920478 |
| Xog Operating LLC |
945921 |