| 1 | Dakota Exploration LLC | Tulsa, OK 74136 | Oil & Gas Operator | Feb 2026 |
| 2 | Danmar Production Company LLC | | Oil & Gas Operator | Dec 2022 |
| 3 | Declar Oil & Gas Inc | | Oil & Gas Operator | Dec 2012 |
| 4 | Desert Eagle Operating LLC | | Gas Operator | Jan 2026 |
| 5 | Developing Equities Group LLC | | Oil & Gas Operator | Feb 2008 |
| 6 | Diamond Oil And Gas, Inc. | Kalamazoo, MI 49001 | Oil & Gas Operator | Apr 2026 |
| 7 | Diamond Operating Inc | | Oil & Gas Operator | Aug 2021 |
| 8 | Diamondback Oil Partners LLP | Arvada, CO 80004 | Oil & Gas Operator | Sep 2016 |
| 9 | Diversified Energy LLC | Parker, CO 80138 | Oil & Gas Operator | Dec 2025 |
| 10 | Diversified Operating Corp. | Golden, CO 80401 | Oil & Gas Operator | Oct 2012 |
| 11 | Donnelly Casing Pulling Co | | Oil Operator | Aug 2020 |
| 12 | Dover Atwood Corp. | Massillon, OH 44646 | Oil & Gas Operator | Dec 2025 |
| 13 | Dugan Production Corp | Farmington, NM 87499 | Oil & Gas Operator | Feb 2026 |
| 14 | Duke Gas Company LLC | | Oil & Gas Operator | Jan 2026 |
| 15 | Dunamis Energy Operating LLC | | Oil & Gas Operator | Dec 2025 |
| 16 | Dunne Equities Operating, Inc. | Houston, TX 77057 | Oil & Gas Operator | Aug 2022 |