| 1 | D90 Energy, LLC | Houston, TX 77024 | Oil & Gas Operator | Oct 2025 |
| 2 | Dabb Energy Company | Fort Worth, TX 76132 | Oil & Gas Operator | Aug 2020 |
| 3 | Dakota Crude, Inc. | | Oil & Gas Operator | Aug 2025 |
| 4 | Dakota Oil Company | Hebbronville, TX 78361 | Oil & Gas Operator | Oct 2025 |
| 5 | Dakota West Pumping, Inc. | | Oil & Gas Operator | Feb 2004 |
| 6 | Dakota-3 E&P Company, LLC | | Oil & Gas Operator | Jan 2012 |
| 7 | David H Arrington Oil & Gas Inc | Midland, TX 79701 | Oil & Gas Operator | Aug 2025 |
| 8 | Deep Creek Adventures, Co. | | Oil Operator | Dec 2018 |
| 9 | Denali Oil & Gas Management, LLC | Houston, TX 77060 | Oil & Gas Operator | Dec 2012 |
| 10 | Denbury Onshore, LLC | Plano, TX 75024 | Oil & Gas Operator | Oct 2025 |
| 11 | Depco Inc. | Denver, CO 80202 | Oil & Gas Operator | Apr 2014 |
| 12 | Depco, Inc. & Texas Pacific Oil Co. | | Oil Operator | Jul 1995 |
| 13 | Devon Energy Production Company LP | Oklahoma City, OK 73102 | Oil & Gas Operator | Oct 2025 |
| 14 | Diamond S Energy Company | Fort Worth, TX 76132 | Oil & Gas Operator | Oct 2025 |
| 15 | Dome Petroleum Corp | Denver, CO 80202 | Oil & Gas Operator | Dec 2016 |
| 16 | Dominion Oklahoma Texas Expl & Prod Inc | Oklahoma City, OK 73134 | Oil & Gas Operator | Aug 2013 |
| 17 | Donald C. Slawson | | Oil Operator | Jun 1985 |
| 18 | Dorchester Exploration, Inc. | Dallas, TX 75231 | Oil & Gas Operator | Aug 2001 |
| 19 | Double Aa Oil, L.L.C. | | Oil Operator | Aug 2023 |
| 20 | Drawings, LLC | Albuquerque, NM 87109 | Oil Operator | Jun 2025 |
| 21 | Dry Creek Disposal Company, Inc. | | Oil & Gas Operator | Nov 2021 |