| 1 | D & H Production, Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Mar 2024 |
| 2 | D-S-B Properties, Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Sep 2014 |
| 3 | D-S-B Properties, LLC | Kilgore, TX 75663 | Oil & Gas Operator | Sep 2026 |
| 4 | Dale Operating Company | Dallas, TX 75207 | Oil & Gas Operator | Sep 2026 |
| 5 | Dallas Production, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Mar 2021 |
| 6 | Danmark Energy Services, Inc. | White Oak, TX 75693 | Oil & Gas Operator | Apr 2021 |
| 7 | Devon Energy Production Company, L.P. | Oklahoma City, OK 73102 | Oil & Gas Operator | Sep 2026 |
| 8 | Diversified Production LLC | Keithville, LA 71047 | Oil & Gas Operator | Sep 2026 |
| 9 | DNR Oil And Gas, Inc. | Englewood, CO 80155 | Oil & Gas Operator | Jul 2026 |
| 10 | Dominion Oklahoma Texas E&P, Inc | Richmond, VA 23219 | Oil & Gas Operator | Sep 2018 |
| 11 | Donnell Pipe & Supply Co/TX Corp | Kilgore, TX 75663 | Oil & Gas Operator | Mar 2008 |
| 12 | Double Eight Oil Company LLC | Nichols Hill, OK 73116 | Oil & Gas Operator | Sep 2026 |
| 13 | Dreyfus, Louis Natural Gas Corp | Oklahoma City, OK 73134 | Oil & Gas Operator | Nov 2001 |