| 1 | D-Bar Leasing, Inc. | Abilene, TX 79604 | Oil & Gas Operator | Apr 2022 |
| 2 | D. A. B. Oil Service, Inc. | Abilene, TX 79608 | Oil & Gas Operator | Nov 2012 |
| 3 | D.J. & T. Energy | Abilene, TX 79601 | Oil & Gas Operator | Jun 2025 |
| 4 | D.J.F. Services, Inc. | Holdenville, OK 74848 | Oil & Gas Operator | Jun 2025 |
| 5 | D.K.D. | Merkel, TX 79536 | Oil & Gas Operator | Jun 2025 |
| 6 | Daf Operating, LLC | Houston, TX 77005 | Oil & Gas Operator | Jun 2025 |
| 7 | Dakota Resources, Inc. (I) | Midland, TX 79707 | Oil & Gas Operator | Jun 2025 |
| 8 | Dalen Resources Oil & Gas Co. | Dallas, TX 75206 | Oil & Gas Operator | Jun 2010 |
| 9 | Dark Canyon Resources LLC | Refugio, TX 78377 | Oil Operator | Jun 2025 |
| 10 | Davis, Paul Pipe & Supply Inc. | Abilene, TX 79606 | Oil & Gas Operator | Feb 2001 |
| 11 | Deen Drilling Company | Archer City, TX 76351 | Oil & Gas Operator | Jun 2025 |
| 12 | Deep Gully Oil LLC | Houston, TX 77292 | Oil Operator | Jun 2025 |
| 13 | Del Petroleum Corporation | Dallas, TX 75219 | Oil & Gas Operator | Jan 2012 |
| 14 | Delray Oil, Inc. | San Antonio, TX 78209 | Oil & Gas Operator | Jun 2025 |
| 15 | Delta Oil & Gas LTD. | Breckenridge, TX 76424 | Oil & Gas Operator | Jun 2025 |
| 16 | Demand Energy, Inc. | Abilene, TX 79601 | Oil & Gas Operator | Jul 1999 |
| 17 | Dimock Operating Company | Frisco, TX 75034 | Oil & Gas Operator | Jun 2025 |
| 18 | Dino Operating LLC | Throckmorton, TX 76483 | Oil Operator | Jun 2025 |
| 19 | Dixon Exploration Inc | Abilene, TX 79604 | Oil & Gas Operator | Oct 2019 |
| 20 | DJ & T Services, LLC | Abilene, TX 79601 | Oil & Gas Operator | Jun 2025 |
| 21 | DJM Beasley Well Service | Tuscola, TX 79562 | Oil Operator | Jun 2025 |
| 22 | DMS Oil Company | Houston, TX 77042 | Oil & Gas Operator | Mar 2025 |
| 23 | Dobbs Petroleum Co. | Abilene, TX 79606 | Oil & Gas Operator | Jun 2025 |
| 24 | Domino Operations, Inc. | Abilene, TX 79603 | Oil & Gas Operator | Jun 2025 |
| 25 | Double C Operating LLC | Abilene, TX 79602 | Oil Operator | Jun 2025 |
| 26 | Double M Petroproperties, Inc. | Haskell, TX 79521 | Oil & Gas Operator | Jun 2025 |
| 27 | Dove Creek Energy, Inc. | Fort Worth, TX 76121 | Oil & Gas Operator | Jun 2025 |
| 28 | Dove Mineral | Abilene, TX 79601 | Oil & Gas Operator | Dec 2010 |
| 29 | DP2, LLC | Southlake, TX 76092 | Oil & Gas Operator | Jun 2025 |
| 30 | Drillogix Exploration LLC | Breckenridge, TX 76424 | Oil Operator | Jun 2025 |
| 31 | Drum, Delton | Liberty, TX 77575 | Oil & Gas Operator | Jul 2005 |
| 32 | Duncan Drilling Co. | Big Spring, TX 79721 | Oil & Gas Operator | Jun 2025 |
| 33 | Dunigan Petroleum, Inc. | Dallas, TX 75201 | Oil & Gas Operator | Aug 2003 |
| 34 | Dunlap Exploration, Inc. | Fort Worth, TX 76101 | Oil & Gas Operator | Nov 2016 |
| 35 | Durango Operating Co., Inc. | Abilene, TX 79604 | Oil & Gas Operator | Feb 2002 |
| 36 | DWR Oil Company | Merkel, TX 79536 | Oil & Gas Operator | Jun 2025 |
| 37 | Dym Energy, Inc. | Celina, TX 75009 | Oil & Gas Operator | Apr 2018 |