| 1 | D&H-S-S Production Co.,Inc | Corpus Chrsti, TX 78409 | Oil & Gas Operator | Aug 2003 |
| 2 | D&M Operating, L.L.C. | Corpus Chrsti, TX 78414 | Gas Operator | Apr 2025 |
| 3 | D.Y. Exploration, Inc. | Boise, ID 83705 | Oil & Gas Operator | Apr 2025 |
| 4 | Dale Operating Company | Dallas, TX 75201 | Oil & Gas Operator | Apr 2025 |
| 5 | Dale Operations, LLC | Dickinson, TX 77539 | Oil & Gas Operator | Apr 2025 |
| 6 | Dark Horse Producing Of TX, L.P. | Alice, TX 78333 | Oil & Gas Operator | Apr 2025 |
| 7 | DCP Operating Co LP | Houston, TX 77042 | Oil & Gas Operator | Jan 2025 |
| 8 | Devon Energy Production Company LP | Oklahoma City, OK 73102 | Oil & Gas Operator | Apr 2025 |
| 9 | Devon Louisiana Corporation | Houston, TX 77002 | Oil & Gas Operator | Oct 2019 |
| 10 | Dewbre Petroleum Corporation | Corpus Chrsti, TX 78404 | Oil & Gas Operator | Apr 2025 |
| 11 | Diamond "S" Oil, Inc. | Houston, TX 77065 | Oil & Gas Operator | Apr 1994 |
| 12 | Dinero Oil Corporation | Corpus Chrsti, TX 78460 | Oil & Gas Operator | Nov 1999 |
| 13 | Dinero Operating Co | Midland, TX 79702 | Oil & Gas Operator | Apr 2025 |
| 14 | Discorbis Oil Company | San Antonio, TX 78217 | Oil & Gas Operator | Jul 2019 |
| 15 | Discovery Energy Corp. CC | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Apr 2025 |
| 16 | Discovery Petroleum, L.L.C. | Alice, TX 78333 | Oil & Gas Operator | Apr 2025 |
| 17 | Dolphin Petroleum | Alice, TX 78333 | Oil & Gas Operator | Jun 2008 |
| 18 | Dolphin Petroleum, LP | Alice, TX 78333 | Oil & Gas Operator | Apr 2025 |
| 19 | Dorado Oil Company | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Dec 2014 |
| 20 | Double Play Oil & Gas, Inc | Portland, TX 78374 | Oil & Gas Operator | Apr 2025 |
| 21 | Dugger, Glenn | Alice, TX 78332 | Oil & Gas Operator | Nov 2013 |
| 22 | Durst Oil Company | Corpus Chrsti, TX 78477 | Oil & Gas Operator | Sep 2000 |
| 23 | Duster Production, Inc. | Refugio, TX 78377 | Oil & Gas Operator | Oct 2011 |
| 24 | Duval Gas Gathering Corporation | Austin, TX 78711 | Oil & Gas Operator | Apr 2025 |
| 25 | Dynamic Petroleum Res., Inc. | Houston, TX 77068 | Oil & Gas Operator | Jul 1994 |