| 1 | D & B Operating, Inc. | Midland, TX 79701 | Oil & Gas Operator | Dec 2003 |
| 2 | D.J.F. Services, Inc. | Holdenville, OK 74848 | Oil & Gas Operator | Mar 2025 |
| 3 | D.K.D. | Merkel, TX 79536 | Oil & Gas Operator | Mar 2025 |
| 4 | Dakota Resources, Inc. (I) | Midland, TX 79707 | Oil & Gas Operator | Mar 2025 |
| 5 | Dale Operating Company | Dallas, TX 75201 | Oil & Gas Operator | Mar 2025 |
| 6 | Dalen Resources Oil & Gas Co. | Dallas, TX 75206 | Oil & Gas Operator | Jun 2010 |
| 7 | Dallas Petroleum Group, LLC | Dallas, TX 75379 | Oil & Gas Operator | Mar 2025 |
| 8 | Day Resources, Inc. | Midland, TX 79707 | Oil & Gas Operator | Aug 1994 |
| 9 | Del Petroleum Corporation | Dallas, TX 75219 | Oil & Gas Operator | Jan 2012 |
| 10 | Delray Oil, Inc. | San Antonio, TX 78209 | Oil & Gas Operator | Mar 2025 |
| 11 | Delta Oil & Gas Company | Breckenridge, TX 76424 | Oil & Gas Operator | Apr 2003 |
| 12 | Denton Exploration, Inc. | Dallas, TX 75219 | Oil & Gas Operator | Mar 2025 |
| 13 | Desana Development Corporation | Midland, TX 79701 | Oil & Gas Operator | Mar 2025 |
| 14 | Devon Energy Production Company LP | Oklahoma City, OK 73102 | Oil & Gas Operator | Mar 2025 |
| 15 | Dominion Oklahoma Texas E&P, Inc | Richmond, VA 23219 | Oil & Gas Operator | Sep 2018 |
| 16 | Dorado Oil Company | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Dec 2014 |
| 17 | Double Eagle Petroleum Corp | Evansville, IN 47725 | Oil & Gas Operator | Mar 2025 |
| 18 | Double M Petroproperties, Inc. | Haskell, TX 79521 | Oil & Gas Operator | Mar 2025 |
| 19 | Draco Energy, Inc. | Midland, TX 79701 | Oil & Gas Operator | Mar 2025 |
| 20 | Dreyfus, Louis Natural Gas Corp | Oklahoma City, OK 73134 | Oil & Gas Operator | Nov 2001 |
| 21 | Dry Fork Production Co., LLC | Wichita Falls, TX 76307 | Oil & Gas Operator | Mar 2025 |
| 22 | Duncan Drilling Co. | Big Spring, TX 79721 | Oil & Gas Operator | Mar 2025 |
| 23 | Durham, Inc. | Midland, TX 79701 | Oil & Gas Operator | Jul 2016 |
| 24 | Dyad Petroleum Company | Midland, TX 79710 | Oil & Gas Operator | Sep 2021 |
| 25 | Dynamic Production, Inc. | Fort Worth, TX 76106 | Oil & Gas Operator | Mar 2025 |