| 1 | D-Bar Leasing, Inc. | Abilene, TX 79604 | Oil & Gas Operator | Apr 2022 |
| 2 | D-T Development Company | Richardson, TX 75081 | Oil & Gas Operator | Sep 2002 |
| 3 | D. A. B. Oil Service, Inc. | Abilene, TX 79608 | Oil & Gas Operator | Nov 2012 |
| 4 | D.J. & T. Energy | Abilene, TX 79601 | Oil & Gas Operator | Oct 2025 |
| 5 | D.J.F. Services, Inc. | Holdenville, OK 74848 | Oil & Gas Operator | Oct 2025 |
| 6 | Dabb Energy Company | Fort Worth, TX 76132 | Oil & Gas Operator | Aug 2020 |
| 7 | Dallas Production, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Mar 2021 |
| 8 | Dallas Royalty, Inc. | Jacksboro, TX 76458 | Oil & Gas Operator | Dec 2012 |
| 9 | Dark Canyon Resources LLC | Refugio, TX 78377 | Oil Operator | Oct 2025 |
| 10 | DBC Operating Company LLC | Midlothian, TX 76065 | Oil & Gas Operator | Oct 2025 |
| 11 | Delray Oil, Inc. | San Antonio, TX 78209 | Oil & Gas Operator | Oct 2025 |
| 12 | Demand Energy, Inc. | Abilene, TX 79601 | Oil & Gas Operator | Jul 1999 |
| 13 | Denteco Oil Company LLC | Abilene, TX 79604 | Oil & Gas Operator | Oct 2025 |
| 14 | Diamond S Masada LLC | Magnolia, TX 77354 | Oil & Gas Operator | Oct 2025 |
| 15 | Diller Oil Company | Baird, TX 79504 | Oil Operator | Oct 2025 |
| 16 | Discovery Petroleum, L.L.C. | Alice, TX 78333 | Oil & Gas Operator | Oct 2025 |
| 17 | Dixon Exploration Inc | Abilene, TX 79604 | Oil & Gas Operator | Oct 2019 |
| 18 | DJ & T Services, LLC | Abilene, TX 79601 | Oil & Gas Operator | Oct 2025 |
| 19 | DJM Beasley Well Service | Tuscola, TX 79562 | Oil Operator | Oct 2025 |
| 20 | Dodson, Wayne Consultants, Inc. | Snyder, TX 79549 | Oil & Gas Operator | Jul 2003 |
| 21 | Douglas Investments Inc | Fort Worth, TX 76137 | Oil Operator | Jan 2020 |
| 22 | Dove Creek Energy, Inc. | Fort Worth, TX 76121 | Oil & Gas Operator | Oct 2025 |
| 23 | Drillogix Exploration LLC | Breckenridge, TX 76424 | Oil Operator | Oct 2025 |
| 24 | Drum Oil & Gas, Inc. | Houston, TX 77082 | Oil & Gas Operator | Oct 2025 |
| 25 | Drum, Delton | Liberty, TX 77575 | Oil & Gas Operator | Jul 2005 |
| 26 | Duke, M. L. | Snyder, TX 79549 | Oil & Gas Operator | Mar 2008 |
| 27 | Duncan Energy LLC | Dallas, TX 75231 | Oil & Gas Operator | Oct 2025 |
| 28 | Durango Operating Co., Inc. | Abilene, TX 79604 | Oil & Gas Operator | Feb 2002 |
| 29 | DWR Oil Company | Merkel, TX 79536 | Oil & Gas Operator | Aug 2025 |
| 30 | Dyne Oil & Gas,Inc. | Borger, TX 79008 | Oil & Gas Operator | Dec 2017 |