| 1 | D90 Energy, LLC | Houston, TX 77024 | Oil & Gas Operator | Oct 2025 |
| 2 | Dale Operating Company | Dallas, TX 75201 | Oil & Gas Operator | Oct 2025 |
| 3 | Dallas Petroleum Group, LLC | Dallas, TX 75379 | Oil & Gas Operator | Oct 2025 |
| 4 | Dallas Production, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Mar 2021 |
| 5 | Dantex Oil & Gas, Inc. | Dallas, TX 75225 | Oil & Gas Operator | Aug 2003 |
| 6 | Davidson Production Company, LLC | Bertram, TX 78605 | Oil Operator | Oct 2025 |
| 7 | Davidson, Grover R. | Bertram, TX 78605 | Oil & Gas Operator | Oct 2025 |
| 8 | Davis Bros. Oil Producers, Inc. | Tulsa, OK 74119 | Oil & Gas Operator | Apr 2020 |
| 9 | Davis, A. L. Production Co.,Inc. | Van Vleck, TX 77482 | Oil & Gas Operator | Aug 2003 |
| 10 | Davis, C. O. Production Co. | Bay City, TX 77414 | Oil & Gas Operator | Oct 2025 |
| 11 | Davis, J. R. Oil Company | Sweeny, TX 77480 | Oil & Gas Operator | Oct 2025 |
| 12 | Davis, Larry D. | Boling, TX 77420 | Oil & Gas Operator | Oct 2025 |
| 13 | Daylight Petroleum LLC | Houston, TX 77052 | Oil & Gas Operator | Oct 2025 |
| 14 | DCP Operating Co LP | Houston, TX 77042 | Oil & Gas Operator | May 2025 |
| 15 | Decker Operating Co., L.L.C. | Houston, TX 77008 | Oil & Gas Operator | Oct 2025 |
| 16 | Del Petroleum Corporation | Dallas, TX 75219 | Oil & Gas Operator | Jan 2012 |
| 17 | Delaware Davis Petroleum Corp. | Houston, TX 77056 | Oil & Gas Operator | Jan 2000 |
| 18 | Delco Operating Company LP | Houston, TX 77056 | Oil & Gas Operator | May 2020 |
| 19 | Delray Oil, Inc. | San Antonio, TX 78209 | Oil & Gas Operator | Oct 2025 |
| 20 | Denovo Oil & Gas, Inc. | Houston, TX 77210 | Oil & Gas Operator | May 1995 |
| 21 | Devon Energy Production Company LP | Oklahoma City, OK 73102 | Oil & Gas Operator | Oct 2025 |
| 22 | Dewbre Petroleum Corporation | Corpus Chrsti, TX 78404 | Oil & Gas Operator | Oct 2025 |
| 23 | Diasu Oil & Gas Co., Inc. | Houston, TX 77002 | Oil & Gas Operator | Mar 2016 |
| 24 | Dinero Oil Corporation | Corpus Chrsti, TX 78460 | Oil & Gas Operator | Nov 1999 |
| 25 | Discovery Energy Corp. CC | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Oct 2025 |
| 26 | DKW Energy, Inc. | Sherman Oaks, CA 91403 | Oil & Gas Operator | Oct 2025 |
| 27 | DMS Oil Company | Houston, TX 77042 | Oil & Gas Operator | Aug 2025 |
| 28 | Dominion Exploration & Production Inc | Houston, TX 77060 | Oil & Gas Operator | Apr 2015 |
| 29 | Dominion Oklahoma Texas E&P, Inc | Richmond, VA 23219 | Oil & Gas Operator | Sep 2018 |
| 30 | Dominion Production Company, LLC | Tampa, FL 33606 | Oil & Gas Operator | Oct 2025 |
| 31 | Dorado Oil Company | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Oct 2013 |
| 32 | Double Play Oil & Gas, Inc | Portland, TX 78374 | Oil & Gas Operator | Oct 2025 |
| 33 | Dreyfus, Louis Natural Gas Corp | Oklahoma City, OK 73134 | Oil & Gas Operator | Nov 2001 |
| 34 | Driscoll S.W.D. Inc. | San Antonio, TX 78229 | Oil & Gas Operator | Oct 2025 |
| 35 | Duderstadt, A. R. | Boling, TX 77420 | Oil & Gas Operator | Oct 2025 |
| 36 | Duncan Oil Inc | Denver, CO 80210 | Oil & Gas Operator | Jun 2016 |
| 37 | Dynamic Production, Inc. | Fort Worth, TX 76106 | Oil & Gas Operator | Oct 2025 |