| 1 | D-S-B Properties, Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Sep 2014 |
| 2 | Dallas Production Company LLC | Dallas, TX 75206 | Oil & Gas Operator | Feb 2026 |
| 3 | Dallas Production, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Mar 2021 |
| 4 | Dearing, Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Mar 2021 |
| 5 | Decker Operating Co., L.L.C. | Houston, TX 77008 | Oil & Gas Operator | Feb 2026 |
| 6 | Deguello Operating LLC | College Sta, TX 77840 | Oil & Gas Operator | Feb 2026 |
| 7 | Delaware Davis Petroleum Corp. | Houston, TX 77056 | Oil & Gas Operator | Jan 2000 |
| 8 | Devon Energy Operating Co., L.P. | Oklahoma City, OK 73102 | Oil & Gas Operator | Jun 2009 |
| 9 | Devon Energy Production Company, L.P. | Oklahoma City, OK 73102 | Oil & Gas Operator | Feb 2026 |
| 10 | Devon Gas Services, L.P. | Oklahoma City, OK 73102 | Oil & Gas Operator | Nov 2015 |
| 11 | Diamond Oil And Gas, Inc. | Kalamazoo, MI 49001 | Oil & Gas Operator | Feb 2026 |
| 12 | Diasu Oil & Gas Co., Inc. | Houston, TX 77002 | Oil & Gas Operator | Mar 2016 |
| 13 | Diversified Production LLC | Keithville, LA 71047 | Oil & Gas Operator | Feb 2026 |
| 14 | Douglas Petroleum Inc. | Spring, TX 77379 | Oil & Gas Operator | Nov 2010 |
| 15 | Dynamic Of Texas, Inc. | Lafayette, LA 70505 | Oil & Gas Operator | Aug 2003 |
| 16 | Dynamic Production, Inc. | Fort Worth, TX 76102 | Oil & Gas Operator | Feb 2026 |