| 1 | D & G Roustabout Service | | Oil & Gas Operator | Jan 2024 |
| 2 | D90 Energy, LLC | Austin, TX 78746 | Oil & Gas Operator | Nov 2024 |
| 3 | Dakota Exploration LLC | Tulsa, OK 74136 | Oil & Gas Operator | Aug 2024 |
| 4 | Daniels Petroleum Co | Denver, CO 80202 | Oil & Gas Operator | Mar 2003 |
| 5 | Darrah Oil Company LLC | Wichita, KS 67201 | Oil & Gas Operator | Nov 2024 |
| 6 | Dart Oil Co | Parker, CO 80134 | Oil & Gas Operator | Dec 2023 |
| 7 | Davis, LLC* Edward Mike | | Oil & Gas Operator | Sep 2015 |
| 8 | Dawson Resources Inc | Franktown, CO 80116 | Oil & Gas Operator | Mar 2015 |
| 9 | Declar Oil & Gas Inc | | Oil & Gas Operator | Dec 2012 |
| 10 | Dejour Energy (USA) Corporation | | Oil & Gas Operator | Jun 2014 |
| 11 | Delek Energy Systems Us Inc | Denver, CO 80202 | Oil & Gas Operator | Oct 2011 |
| 12 | Desert Eagle Operating LLC | | Gas Operator | Aug 2024 |
| 13 | Devon Louisiana Corporation | Houston, TX 77002 | Oil & Gas Operator | Oct 2019 |
| 14 | Diamond Oil And Gas, Inc. | Kalamazoo, MI 49001 | Oil & Gas Operator | Nov 2024 |
| 15 | Diamond Operating, Inc. | | Oil & Gas Operator | Feb 2022 |
| 16 | Diamondback Oil Partners LLP | Arvada, CO 80004 | Oil & Gas Operator | Dec 2016 |
| 17 | Direct Petroleum Exploration Inc | | Oil & Gas Operator | Aug 2010 |
| 18 | Diversified Energy LLC | Parker, CO 80138 | Oil & Gas Operator | Jul 2024 |
| 19 | Diversified Operating Corporation | Golden, CO 80401 | Oil & Gas Operator | Oct 2012 |
| 20 | DJ Production Services Inc | | Oil & Gas Operator | Sep 2012 |
| 21 | DJ Resources Inc | Bowie, TX 76230 | Oil & Gas Operator | Nov 2017 |
| 22 | Dominion Oklahoma Texas Exploration & Production | Houston, TX 77060 | Oil & Gas Operator | Dec 2006 |
| 23 | Donnelly Casing Pulling Co | | Oil Operator | Aug 2020 |
| 24 | Dover Atwood Corporation | Massillon, OH 44646 | Oil & Gas Operator | Dec 2023 |
| 25 | Drindak* Jon | | Oil Operator | Aug 2013 |
| 26 | Dugan Production Corp | Farmington, NM 87499 | Oil & Gas Operator | Sep 2024 |
| 27 | Duke Gas Company LLC | | Gas Operator | Sep 2024 |
| 28 | Duncan Energy Company | Denver, CO 80202 | Oil & Gas Operator | Mar 2008 |
| 29 | Duncan Oil Inc | Denver, CO 80210 | Oil & Gas Operator | Jun 2016 |
| 30 | Dunne Equities Operating Inc | Houston, TX 77057 | Oil & Gas Operator | Aug 2022 |