| 1 | Dakota Resources, Inc. (I) | Midland, TX 79707 | Oil & Gas Operator | Oct 2025 |
| 2 | Dallas Production Company LLC | Dallas, TX 75206 | Oil & Gas Operator | Oct 2025 |
| 3 | Delray Oil, Inc. | San Antonio, TX 78209 | Oil & Gas Operator | Oct 2025 |
| 4 | Devon Energy Corp (Nevada) | Oklahoma City, OK 73102 | Oil & Gas Operator | Feb 2017 |
| 5 | Devon Energy Production Company LP | Oklahoma City, OK 73102 | Oil & Gas Operator | Oct 2025 |
| 6 | Devx Operating Company | Frisco, TX 75034 | Oil & Gas Operator | Feb 2004 |
| 7 | Diamondback E&P LLC | Midland, TX 79701 | Oil & Gas Operator | Oct 2025 |
| 8 | Discovery Natural Resources LLC | Denver, CO 80202 | Oil & Gas Operator | Oct 2025 |
| 9 | Discovery Operating Inc | Midland, TX 79705 | Oil & Gas Operator | Oct 2025 |
| 10 | Dittman, D. W. | Big Lake, TX 76932 | Oil & Gas Operator | Mar 2007 |
| 11 | DLB Oil & Gas, Inc. | Big Lake, TX 76932 | Oil & Gas Operator | Oct 2025 |
| 12 | Dominion Oklahoma Texas E&P, Inc | Richmond, VA 23219 | Oil & Gas Operator | Sep 2018 |
| 13 | Dorado Oil Company | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Oct 2013 |
| 14 | Double Eagle Operating, LLC | Fort Worth, TX 76113 | Oil & Gas Operator | Oct 2025 |
| 15 | Dove Creek Energy, Inc. | Fort Worth, TX 76121 | Oil & Gas Operator | Oct 2025 |
| 16 | Dreyfus, Louis Natural Gas Corp | Oklahoma City, OK 73134 | Oil & Gas Operator | Nov 2001 |
| 17 | DSR Oil & Gas, Inc. | Monahans, TX 79756 | Oil & Gas Operator | Oct 2025 |
| 18 | Dunigan Petroleum, Inc. | Dallas, TX 75201 | Oil & Gas Operator | Aug 2003 |