| 1 | D & R Enterprises | Eastland, TX 76448 | Oil & Gas Operator | Oct 2020 |
| 2 | D-Bar Leasing, Inc. | Abilene, TX 79604 | Oil & Gas Operator | Apr 2022 |
| 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 | Feb 2026 |
| 5 | Dabb Energy Company | Fort Worth, TX 76132 | Oil & Gas Operator | Aug 2020 |
| 6 | Dahab Energy Inc. | Dallas, TX 75225 | Oil & Gas Operator | Feb 2026 |
| 7 | Dallas Production Company LLC | Dallas, TX 75206 | Oil & Gas Operator | Feb 2026 |
| 8 | Dallas Production, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Mar 2021 |
| 9 | Darley Enterprises, Inc. | Brownwood, TX 76801 | Oil & Gas Operator | Jan 2012 |
| 10 | Dart Oil & Gas Corporation | Mason, MI 48854 | Oil & Gas Operator | Jun 2018 |
| 11 | Dartex Energy Inc | Graham, TX 76450 | Oil & Gas Operator | Feb 2026 |
| 12 | Dedica Energy Corporation | Mattoon, IL 61938 | Oil & Gas Operator | Mar 2008 |
| 13 | Delaney Oil And Gas Company | Wichita Falls, TX 76307 | Oil & Gas Operator | Feb 2026 |
| 14 | Delta Oil & Gas Company | Breckenridge, TX 76424 | Oil & Gas Operator | Apr 2003 |
| 15 | Delta Oil & Gas LTD. | Breckenridge, TX 76424 | Oil & Gas Operator | Feb 2026 |
| 16 | Demoss, L. V. | Graham, TX 76450 | Oil & Gas Operator | May 2004 |
| 17 | Denoco Inc. | Plano, TX 75086 | Oil & Gas Operator | Mar 2008 |
| 18 | Denton Exploration, Inc. | Dallas, TX 75219 | Oil & Gas Operator | Feb 2026 |
| 19 | Desana Development Corporation | Midland, TX 79701 | Oil & Gas Operator | Feb 2026 |
| 20 | Devon Energy Production Company, L.P. | Oklahoma City, OK 73102 | Oil & Gas Operator | Feb 2026 |
| 21 | Devon Gas Services, L.P. | Oklahoma City, OK 73102 | Oil & Gas Operator | Nov 2015 |
| 22 | Diamond S Energy Company | Fort Worth, TX 76132 | Oil & Gas Operator | Feb 2026 |
| 23 | Dimock Operating Company | Frisco, TX 75034 | Oil & Gas Operator | Feb 2026 |
| 24 | Dodson Prairie Oil & Gas LLC | San Antonio, TX 78205 | Gas Operator | Feb 2026 |
| 25 | Dooley, Jeff | Breckenridge, TX 76424 | Oil & Gas Operator | Jul 2012 |
| 26 | Dorfman Production Company | Beloit, OH 44609 | Oil & Gas Operator | Feb 2026 |
| 27 | Double Eagle Petroleum Corp | Evansville, IN 47725 | Oil & Gas Operator | Feb 2026 |
| 28 | Double T Royalty Co., Inc. | Mineral Wells, TX 76068 | Oil & Gas Operator | Feb 2026 |
| 29 | Double U Oil Co., LTD. | San Antonio, TX 78217 | Oil & Gas Operator | May 2000 |
| 30 | Dove Creek Energy, Inc. | Fort Worth, TX 76121 | Oil & Gas Operator | Feb 2026 |
| 31 | Dowell Oil & Gas | Stephenville, TX 76401 | Oil & Gas Operator | Feb 2026 |
| 32 | Draco Energy, Inc. | Midland, TX 79701 | Oil & Gas Operator | Feb 2026 |
| 33 | Drennan, D. E. | Graham, TX 76450 | Oil & Gas Operator | Dec 2011 |
| 34 | Drillogix Exploration LLC | Breckenridge, TX 76424 | Oil Operator | Feb 2026 |
| 35 | Dry Fork Production Co | Wichita Falls, TX 76301 | Oil Operator | Apr 2003 |
| 36 | Dry Fork Production Co., LLC | Wichita Falls, TX 76307 | Oil & Gas Operator | Feb 2026 |
| 37 | Dte Gas Resources, Inc. | Fort Worth, TX 76102 | Oil & Gas Operator | Nov 2007 |
| 38 | Dte Gas Resources, LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Feb 2014 |
| 39 | Dunlap Exploration, Inc. | Fort Worth, TX 76101 | Oil & Gas Operator | Nov 2016 |
| 40 | Dynamic Production, Inc. | Fort Worth, TX 76102 | Oil & Gas Operator | Feb 2026 |