| 1 | D. O. G. Operating, LLC | Port Aransas, TX 78373 | Oil & Gas Operator | Oct 2025 |
| 2 | Dale Operating Company | Dallas, TX 75201 | Oil & Gas Operator | Oct 2025 |
| 3 | Dallas Production, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Mar 2021 |
| 4 | Dark Horse Producing Of TX, L.P. | Alice, TX 78333 | Oil & Gas Operator | Oct 2025 |
| 5 | DCP Operating Co LP | Houston, TX 77042 | Oil & Gas Operator | May 2025 |
| 6 | Dekalb Energy Company | Oklahoma City, OK 73134 | Oil & Gas Operator | Oct 1996 |
| 7 | Delray Oil, Inc. | San Antonio, TX 78209 | Oil & Gas Operator | Oct 2025 |
| 8 | Delta Exploration Company Inc | Denver, CO 80202 | Oil & Gas Operator | Oct 2025 |
| 9 | Devon Energy Operating Co., L.P. | Oklahoma City, OK 73102 | Oil & Gas Operator | Jun 2009 |
| 10 | Devon Energy Production Company LP | Oklahoma City, OK 73102 | Oil & Gas Operator | Oct 2025 |
| 11 | Devon Louisiana Corporation | Houston, TX 77002 | Oil & Gas Operator | Oct 2019 |
| 12 | Dewbre Petroleum Corporation | Corpus Chrsti, TX 78404 | Oil & Gas Operator | Oct 2025 |
| 13 | Dinero Oil Corporation | Corpus Chrsti, TX 78460 | Oil & Gas Operator | Nov 1999 |
| 14 | Dirnett, Inc. | Tuleta, TX 78162 | Oil & Gas Operator | Oct 2025 |
| 15 | DKW Energy, Inc. | Sherman Oaks, CA 91403 | Oil & Gas Operator | Oct 2025 |
| 16 | Dolch Production, Inc. | San Antonio, TX 78248 | Oil & Gas Operator | Jul 1996 |
| 17 | Dolphin Petroleum | Alice, TX 78333 | Oil & Gas Operator | Jun 2008 |
| 18 | Dominion Oklahoma Texas E&P, Inc | Richmond, VA 23219 | Oil & Gas Operator | Sep 2018 |
| 19 | Dorado Drilling, Inc. | Gulfport, MS 39501 | Oil & Gas Operator | Oct 2025 |
| 20 | Dreyfus, Louis Natural Gas Corp | Oklahoma City, OK 73134 | Oil & Gas Operator | Nov 2001 |
| 21 | Drillers Energy Search, Inc | Denver, CO 80202 | Oil & Gas Operator | Aug 1996 |
| 22 | Driscoll S.W.D. Inc. | San Antonio, TX 78229 | Oil & Gas Operator | Oct 2025 |
| 23 | Dynamic Production, Inc. | Fort Worth, TX 76106 | Oil & Gas Operator | Oct 2025 |