| 1 | D & B Operating, Inc. | Midland, TX 79701 | Oil & Gas Operator | Dec 2003 |
| 2 | D & V Oil Co., LP | San Angelo, TX 76909 | Oil & Gas Operator | Jan 2019 |
| 3 | D G D Oil Co. | Imperial, TX 79743 | Oil & Gas Operator | Jun 2025 |
| 4 | Darco Operators | Big Lake, TX 76932 | Oil & Gas Operator | Jun 2025 |
| 5 | DCP Operating Co LP | Houston, TX 77042 | Oil & Gas Operator | Mar 2025 |
| 6 | De Central Operating, LLC | Fort Worth, TX 76107 | Oil & Gas Operator | Jun 2025 |
| 7 | De IV Operating, LLC | Midland, TX 79701 | Oil & Gas Operator | Jun 2025 |
| 8 | De Operating LLC | Austin, TX 78701 | Oil & Gas Operator | Apr 2017 |
| 9 | De V Operating, LLC | Fort Worth, TX 76107 | Oil Operator | Feb 2025 |
| 10 | De3 Operating LLC | Irving, TX 75038 | Oil & Gas Operator | Jun 2021 |
| 11 | Devon Energy Corp (Nevada) | Oklahoma City, OK 73102 | Oil & Gas Operator | Feb 2017 |
| 12 | Devon Energy Production Company LP | Oklahoma City, OK 73102 | Oil & Gas Operator | Jun 2025 |
| 13 | Devx Operating Company | Frisco, TX 75034 | Oil & Gas Operator | Feb 2004 |
| 14 | Diamondback E&P LLC | Midland, TX 79701 | Oil & Gas Operator | Jun 2025 |
| 15 | Digital Operating Company LLC | Boerne, TX 78006 | Oil & Gas Operator | Jun 2025 |
| 16 | Discovery Natural Resources LLC | Denver, CO 80202 | Oil & Gas Operator | Jun 2025 |
| 17 | Discovery Operating Inc | Midland, TX 79705 | Oil & Gas Operator | Jun 2025 |
| 18 | Dittman, D. W. | Big Lake, TX 76932 | Oil & Gas Operator | Mar 2007 |
| 19 | DLB Oil & Gas, Inc. | Big Lake, TX 76932 | Oil & Gas Operator | Jun 2025 |
| 20 | Dominion Natural Resources LLC | Dallas, TX 75367 | Oil & Gas Operator | Jun 2025 |
| 21 | Dorado Oil Company | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Oct 2013 |
| 22 | Double Eagle Operating, LLC | Fort Worth, TX 76113 | Oil & Gas Operator | Jun 2025 |
| 23 | Driftwood Energy Operating, LLC | Dallas, TX 75219 | Oil & Gas Operator | Dec 2022 |
| 24 | Dugan Production Corp | Farmington, NM 87499 | Oil & Gas Operator | Apr 2025 |
| 25 | Dunigan Petroleum, Inc. | Dallas, TX 75201 | Oil & Gas Operator | Aug 2003 |
| 26 | Durham, Inc. | Midland, TX 79701 | Oil & Gas Operator | Jul 2016 |