| 1 | D. G. Oil Co. | Dennis, TX 76439 | Oil & Gas Operator | Oct 2025 |
| 2 | Dahab Energy Inc. | Dallas, TX 75225 | Oil & Gas Operator | Oct 2025 |
| 3 | Dalf Energy LLC | Pampa, TX 79066 | Oil & Gas Operator | Oct 2025 |
| 4 | Dallas Petroleum Group, LLC | Dallas, TX 75379 | Oil & Gas Operator | Oct 2025 |
| 5 | Dallas Production Company LLC | Dallas, TX 75206 | Oil & Gas Operator | Oct 2025 |
| 6 | Dallas Production, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Mar 2021 |
| 7 | Daylight Petroleum LLC | Houston, TX 77052 | Oil & Gas Operator | Oct 2025 |
| 8 | DDC Production Company | Archer City, TX 76351 | Oil Operator | Oct 2025 |
| 9 | De Larios, R. V., LTD. | Wichita Falls, TX 76308 | Oil & Gas Operator | Oct 2025 |
| 10 | Decleva, Paul | Wichita Falls, TX 76302 | Oil & Gas Operator | Dec 2020 |
| 11 | Deen Drilling Company | Archer City, TX 76351 | Oil & Gas Operator | Oct 2025 |
| 12 | Del Mar | Holliday, TX 76366 | Oil & Gas Operator | Oct 2025 |
| 13 | Del Mar Energy, Inc. | Van Alstyne, TX 75495 | Oil & Gas Operator | Oct 2025 |
| 14 | Delray Oil, Inc. | San Antonio, TX 78209 | Oil & Gas Operator | Oct 2025 |
| 15 | Demoss, L. V. | Graham, TX 76450 | Oil & Gas Operator | May 2004 |
| 16 | Den-Kay Corp. | Plano, TX 75074 | Oil Operator | Aug 2009 |
| 17 | Denali Petroleum, LLC | Arlington, TX 76006 | Oil Operator | Mar 2021 |
| 18 | Denman-Friesen Co. | Lufkin, TX 75901 | Oil & Gas Operator | Nov 2006 |
| 19 | Denoco Inc. | Plano, TX 75086 | Oil & Gas Operator | Mar 2008 |
| 20 | Denton Exploration, Inc. | Dallas, TX 75219 | Oil & Gas Operator | Oct 2025 |
| 21 | Diamond Energy, Inc. | Sherman, TX 75091 | Oil & Gas Operator | Oct 2025 |
| 22 | Dick Lindsay Oil Company, Inc. | Graham, TX 76450 | Oil Operator | Oct 2025 |
| 23 | Dillard & Dillard Inc. | Holliday, TX 76366 | Oil & Gas Operator | Oct 2025 |
| 24 | Dimock Operating Company | Frisco, TX 75034 | Oil & Gas Operator | Oct 2025 |
| 25 | Dixie Drilling Company, Inc. | Sherman, TX 75090 | Oil & Gas Operator | Nov 2011 |
| 26 | DM Backhoe Service | Graham, TX 76450 | Oil & Gas Operator | Oct 2025 |
| 27 | Donnell, Louis, Jr. | South Bend, TX 76481 | Oil & Gas Operator | Mar 2008 |
| 28 | Double Barrel Operating Limited Liability Company | Wichita Falls, TX 76308 | Oil Operator | Oct 2025 |
| 29 | Double Eagle Petroleum Corp | Evansville, IN 47725 | Oil & Gas Operator | Oct 2025 |
| 30 | Double K Production | Graham, TX 76450 | Oil & Gas Operator | Sep 2014 |
| 31 | Drennan, D. E. | Graham, TX 76450 | Oil & Gas Operator | Dec 2011 |
| 32 | Drillogix Exploration LLC | Breckenridge, TX 76424 | Oil Operator | Oct 2025 |
| 33 | Dry Fork Production Co | Wichita Falls, TX 76301 | Oil Operator | Apr 2003 |
| 34 | Dry Fork Production Co., LLC | Wichita Falls, TX 76307 | Oil & Gas Operator | Oct 2025 |
| 35 | Duke Operating Company | Graham, TX 76450 | Oil Operator | Oct 2025 |
| 36 | Duncan Land & Exploration, Inc. | Graham, TX 76450 | Oil & Gas Operator | Oct 2025 |
| 37 | Dunlap, Rodge | Olney, TX 76374 | Oil & Gas Operator | Aug 2002 |
| 38 | Dym Energy, Inc. | Celina, TX 75009 | Oil & Gas Operator | Apr 2018 |
| 39 | Dynamic Production, Inc. | Fort Worth, TX 76106 | Oil & Gas Operator | Oct 2025 |