| 1 | D & R Energy | Spencer, WV 25276-0000 | Oil & Gas Operator | Dec 2021 |
| 2 | Davisson, Ancil | | Oil & Gas Operator | Oct 2001 |
| 3 | Denex Petroleum Corp. | Buckhannon, WV 26201 | Oil & Gas Operator | Dec 2021 |
| 4 | Deran Resources, Inc. | Spencer, WV 25276 | Oil & Gas Operator | Dec 2021 |
| 5 | Devon Petroleum Corp. | Marietta, OH 45750 | Oil & Gas Operator | Dec 1996 |
| 6 | Devonian Gas Production, Inc. | Buckhannon, WV 26201 | Oil & Gas Operator | Dec 2021 |
| 7 | Diversified Production LLC | Keithville, LA 71047 | Oil & Gas Operator | Mar 2025 |
| 8 | Diversified Resources, Inc. | Jackson Center, PA 16133 | Oil & Gas Operator | Dec 2020 |
| 9 | Dominion Energy Transmission, Inc. | | Oil & Gas Operator | Dec 2019 |
| 10 | Dominion Exploration & Production Inc | Houston, TX 77060 | Oil & Gas Operator | Apr 2015 |
| 11 | Dorward Energy Corporation | Saint Petersburg, FL 33701-3255 | Oil & Gas Operator | Dec 2024 |