| 1 | D-Mil Production Inc | Argyle, TX 76226 | Oil & Gas Operator | Dec 2025 |
| 2 | Dakota Oil Company | Hebbronville, TX 78361 | Oil & Gas Operator | Dec 2025 |
| 3 | Dallas Petroleum Group, LLC | Dallas, TX 75379 | Oil & Gas Operator | Dec 2025 |
| 4 | Davis Asset Management, Inc. | Houston, TX 77010 | Oil & Gas Operator | Dec 2004 |
| 5 | Davis Southern Operating Co LLC | Houston, TX 77004 | Oil & Gas Operator | Dec 2025 |
| 6 | Delaware Davis Petroleum Corp. | Houston, TX 77056 | Oil & Gas Operator | Jan 2000 |
| 7 | Delray Oil, Inc. | San Antonio, TX 78209 | Oil & Gas Operator | Dec 2025 |
| 8 | Denali Oil & Gas Management LLC | Houston, TX 77060 | Oil & Gas Operator | Dec 2012 |
| 9 | Devon Energy Production Company, L.P. | Oklahoma City, OK 73102 | Oil & Gas Operator | Dec 2025 |
| 10 | Devon Louisiana Corporation | Houston, TX 77002 | Oil & Gas Operator | Oct 2019 |
| 11 | Dewbre Petroleum Corporation | Corpus Chrsti, TX 78404 | Oil & Gas Operator | Dec 2025 |
| 12 | Digital Operating Company LLC | Boerne, TX 78006 | Oil & Gas Operator | Dec 2025 |
| 13 | Dirks, R.W. Pet. Eng. Inc. | Tuleta, TX 78162 | Oil & Gas Operator | Jul 1999 |
| 14 | DKW Energy, Inc. | Sherman Oaks, CA 91403 | Oil & Gas Operator | Dec 2025 |
| 15 | DML Exploration, Inc. | San Antonio, TX 78217 | Oil & Gas Operator | Dec 2025 |
| 16 | DMS Oil Company | Houston, TX 77042 | Oil & Gas Operator | Sep 2025 |
| 17 | Dolphin Petroleum | Alice, TX 78333 | Oil & Gas Operator | Jun 2008 |
| 18 | Dorado Oil Company | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Oct 2013 |
| 19 | Double Eagle Petroleum Corp | Evansville, IN 47725 | Oil & Gas Operator | Dec 2025 |
| 20 | Double Play Oil & Gas | Portland, TX 78374 | Oil & Gas Operator | Dec 2001 |
| 21 | Double Play Oil & Gas, Inc | Portland, TX 78374 | Oil & Gas Operator | Dec 2025 |
| 22 | Drillers Energy Search, Inc | Denver, CO 80202 | Oil & Gas Operator | Aug 1996 |
| 23 | Dynamic Production, Inc. | Fort Worth, TX 76102 | Oil & Gas Operator | Dec 2025 |