| 1 | Dailey Oil And Gas LLC | | Oil & Gas Operator | Jun 2019 |
| 2 | Dalen Resources Oil & Gas Co. | Dallas, TX 75206 | Oil & Gas Operator | Jun 2010 |
| 3 | Damson Oil Corporation | Houston, TX 77210 | Oil & Gas Operator | Mar 2005 |
| 4 | Dant Operating Company Inc. | | Oil & Gas Operator | Jan 1989 |
| 5 | Davis Petroleum Corp. | Houston, TX 77027 | Oil & Gas Operator | Oct 2025 |
| 6 | Daylight Petroleum LLC | Houston, TX 77052 | Oil & Gas Operator | Oct 2025 |
| 7 | DBL DRLG.&Prod. Services, Inc. | | Oil & Gas Operator | Jul 1997 |
| 8 | Deck Oil Company | Tulsa, OK 74101 | Oil & Gas Operator | Jun 2020 |
| 9 | Delta Development Co. Inc. | | Oil & Gas Operator | Dec 1988 |
| 10 | Delta Petroleum Corp Of Co | | Oil & Gas Operator | Oct 2010 |
| 11 | Denbury Management, Inc. | Dallas, TX 75252 | Oil & Gas Operator | Dec 1999 |
| 12 | Denbury Onshore, LLC | Plano, TX 75024 | Oil & Gas Operator | Oct 2025 |
| 13 | Denbury Resources Inc. | Plano, TX 75024 | Oil & Gas Operator | Dec 2003 |
| 14 | Denovo Oil & Gas, Inc. | Houston, TX 77210 | Oil & Gas Operator | May 1995 |
| 15 | Despot Exploration, Inc. | | Oil & Gas Operator | Apr 1990 |
| 16 | Destin Operating Company, Inc. | | Oil & Gas Operator | Jan 2023 |
| 17 | Devon Corporation | | Oil Operator | Oct 1981 |
| 18 | Devon Energy Corp (Nevada) | Oklahoma City, OK 73102 | Oil & Gas Operator | Feb 2017 |
| 19 | Devon Energy Corporation | Oklahoma City, OK 73102 | Oil & Gas Operator | Dec 2009 |
| 20 | Devon Energy Production Company LP | Oklahoma City, OK 73102 | Oil & Gas Operator | Oct 2025 |
| 21 | Diamond S Operating Co. | | Oil & Gas Operator | Oct 1992 |
| 22 | Diamond Shamrock Corp | Amarillo, TX 79105 | Oil & Gas Operator | Jan 1987 |
| 23 | Diamond Shamrock Expl. Co. | | Oil & Gas Operator | Jun 1987 |
| 24 | Diasu Oil & Gas Co., Inc. | Houston, TX 77002 | Oil & Gas Operator | Mar 2016 |
| 25 | Diversified Energy Investments | | Oil & Gas Operator | May 2009 |
| 26 | Dominion Exploration & Production Inc | Houston, TX 77060 | Oil & Gas Operator | Apr 2015 |
| 27 | Dow Intrastate Gas Company | | Oil Operator | Dec 2023 |
| 28 | Drew Cornell, Inc.-Agent | | Oil & Gas Operator | Sep 1990 |
| 29 | Drilling, Operg & Explor, Inc. | | Oil & Gas Operator | Feb 1990 |
| 30 | Dune Operating Company | Dallas, TX 75201 | Oil & Gas Operator | Jun 2016 |
| 31 | Dunhill Expl. & Prod., LLC | | Oil & Gas Operator | Nov 2004 |
| 32 | Dunhill Resources, Inc. | | Oil & Gas Operator | Nov 2005 |
| 33 | Dunn Exploration Company, LLC | | Oil & Gas Operator | Jan 2025 |
| 34 | Dynamic Exploration PTRS, LLC | | Oil & Gas Operator | Nov 2024 |
| 35 | Dynamic Exploration, Inc. | | Oil & Gas Operator | Oct 2003 |