| 1 | Daco, Inc. | Spearman, TX 79081 | Oil & Gas Operator | Oct 2025 |
| 2 | Dakar Operating Company | Pampa, TX 79066 | Oil & Gas Operator | Dec 2001 |
| 3 | Dalf Energy LLC | Pampa, TX 79066 | Oil & Gas Operator | Oct 2025 |
| 4 | Danco Oil & Gas | White Deer, TX 79097 | Oil & Gas Operator | Aug 2013 |
| 5 | Daniels Energy | Pampa, TX 79066 | Oil & Gas Operator | Oct 2025 |
| 6 | Daniels, J.C. Energy | Pampa, TX 79066 | Oil & Gas Operator | Apr 2001 |
| 7 | Darrah Oil Company LLC | Wichita, KS 67201 | Oil & Gas Operator | Oct 2025 |
| 8 | Davenport, Vernon | Shamrock, TX 79079 | Oil & Gas Operator | Mar 2008 |
| 9 | Davenport, Vernon Prod. Co. | Dumas, TX 79029 | Oil & Gas Operator | Jan 2002 |
| 10 | Dawn Oil & Gas Operators Inc. | Borger, TX 79007 | Oil & Gas Operator | Oct 2025 |
| 11 | Dawson, B G Oil & Gas LTD | Dallas, TX 75205 | Oil & Gas Operator | Jul 2024 |
| 12 | DCP Operating Co LP | Houston, TX 77042 | Oil & Gas Operator | May 2025 |
| 13 | Den Cal, Inc. | Borger, TX 79007 | Oil & Gas Operator | Oct 2025 |
| 14 | Denny'S Inc. | Horseshoe Bay, TX 78657 | Oil & Gas Operator | Dec 2000 |
| 15 | Devon Energy Corp (Nevada) | Oklahoma City, OK 73102 | Oil & Gas Operator | Feb 2017 |
| 16 | Devon Energy Production Company LP | Oklahoma City, OK 73102 | Oil & Gas Operator | Oct 2025 |
| 17 | Devon SFS Operating Inc | Oklahoma City, OK 73102 | Oil & Gas Operator | Mar 2008 |
| 18 | Diamond S Energy Company | Fort Worth, TX 76132 | Oil & Gas Operator | Oct 2025 |
| 19 | Dominion Oklahoma Texas E&P, Inc | Richmond, VA 23219 | Oil & Gas Operator | Sep 2018 |
| 20 | Dreyfus, Louis Natural Gas Corp | Oklahoma City, OK 73134 | Oil & Gas Operator | Nov 2001 |
| 21 | DSX Operating Co. | Amarillo, TX 79105 | Oil & Gas Operator | Mar 2008 |
| 22 | Duncan Oil Properties, Inc. | Oklahoma City, OK 73102 | Oil & Gas Operator | Oct 2025 |
| 23 | Dunigan Operating Company, Inc. | Austin, TX 78755 | Oil & Gas Operator | Oct 2025 |
| 24 | Dunne Equities Operating, Inc. | Houston, TX 77057 | Oil & Gas Operator | Aug 2022 |
| 25 | Dunne Equities, Inc. | Wichita, KS 67226 | Oil & Gas Operator | Apr 2014 |
| 26 | Dyne Oil & Gas,Inc. | Borger, TX 79008 | Oil & Gas Operator | Dec 2017 |