| 1 | D C Energy, Inc. | Oklahoma City, OK 73134 | Oil & Gas Operator | Apr 2020 |
| 2 | D.W.P. Production | Perryton, TX 79070 | Oil & Gas Operator | Nov 2020 |
| 3 | Daco, Inc. | Spearman, TX 79081 | Oil & Gas Operator | Oct 2025 |
| 4 | Dalf Energy LLC | Pampa, TX 79066 | Oil & Gas Operator | Oct 2025 |
| 5 | Davis Operating Company | Elysian Field, TX 75642 | Oil & Gas Operator | Oct 2025 |
| 6 | Davis, William H. | Tulsa, OK 74103 | Oil & Gas Operator | Apr 2014 |
| 7 | DCP Operating Co LP | Houston, TX 77042 | Oil & Gas Operator | May 2025 |
| 8 | Deep Reef Industries | Amarillo, TX 79101 | Oil & Gas Operator | Jan 2004 |
| 9 | Devon Energy Corp (Nevada) | Oklahoma City, OK 73102 | Oil & Gas Operator | Feb 2017 |
| 10 | Devon Energy Production Company LP | Oklahoma City, OK 73102 | Oil & Gas Operator | Oct 2025 |
| 11 | Devon Louisiana Corporation | Houston, TX 77002 | Oil & Gas Operator | Oct 2019 |
| 12 | Devon SFS Operating Inc | Oklahoma City, OK 73102 | Oil & Gas Operator | Mar 2008 |
| 13 | Diversified Production LLC | Keithville, LA 71047 | Oil & Gas Operator | Oct 2025 |
| 14 | Dominion Oklahoma Texas E&P, Inc | Richmond, VA 23219 | Oil & Gas Operator | Sep 2018 |
| 15 | Draco Production Company | Tulsa, OK 74133 | Oil & Gas Operator | Jul 2012 |
| 16 | Dreyfus, Louis Natural Gas Corp | Oklahoma City, OK 73134 | Oil & Gas Operator | Nov 2001 |
| 17 | Duncan Energy Company | Denver, CO 80202 | Oil & Gas Operator | Mar 2008 |
| 18 | Duncan Oil Properties, Inc. | Oklahoma City, OK 73102 | Oil & Gas Operator | Oct 2025 |
| 19 | Dunigan Operating Company, Inc. | Austin, TX 78755 | Oil & Gas Operator | Oct 2025 |