| 1 | D D Natural Resources LLC | | Oil & Gas Operator | Sep 2025 |
| 2 | D. A. Stark | | Oil Operator | Dec 1990 |
| 3 | D. E. Craggs Inc. | | Gas Operator | Dec 1993 |
| 4 | D. J. Hatfield | | Oil & Gas Operator | Dec 1994 |
| 5 | D. J. Pickrell Operator | | Gas Operator | Dec 2012 |
| 6 | D. W. Elliott Operating Acct | | Oil & Gas Operator | Dec 1991 |
| 7 | Dalen Resources Oil & Gas Co | Dallas, TX 75206 | Oil & Gas Operator | Jun 2010 |
| 8 | Damson Oil Corporation | Houston, TX 77210 | Oil & Gas Operator | Mar 2005 |
| 9 | Daniel B. Robinett | | Oil & Gas Operator | Dec 1990 |
| 10 | David Radcliff | | Oil & Gas Operator | Dec 2014 |
| 11 | Davis Davis & Davis | | Oil & Gas Operator | Dec 1988 |
| 12 | Davis Investment LLC | | Oil & Gas Operator | Dec 1998 |
| 13 | Daybreak Oil And Gas, Inc. | | Oil & Gas Operator | Sep 2025 |
| 14 | DBF Partners | | Oil Operator | Dec 1986 |
| 15 | Dcor, L.L.C. | Dallas, TX 75225 | Oil & Gas Operator | Sep 2025 |
| 16 | Decalta International Corp | Denver, CO 80202 | Oil & Gas Operator | Mar 2015 |
| 17 | Dekalb Energy Company | Oklahoma City, OK 73134 | Oil & Gas Operator | Oct 1996 |
| 18 | Del Amo Energy Co. | | Oil & Gas Operator | Dec 1987 |
| 19 | Delta Sierra Oil & Gas LLC | | Gas Operator | Jan 2018 |
| 20 | Denali Oil & Gas Management LLC | Houston, TX 77060 | Oil & Gas Operator | Dec 2012 |
| 21 | Department Of Conservation | | Oil Operator | Dec 2005 |
| 22 | Depco Inc. | Denver, CO 80202 | Oil & Gas Operator | Apr 2014 |
| 23 | Deuel Pet. Co. Inc. | | Oil & Gas Operator | Dec 2005 |
| 24 | Deuel Petroleum Calif. Inc. | | Oil & Gas Operator | Dec 2001 |
| 25 | Deuel Petroleum Company Inc. | | Oil & Gas Operator | Dec 1999 |
| 26 | Diversified Resources LLC | | Gas Operator | Aug 2025 |
| 27 | DKM Offshore Energy Inc. | | Oil & Gas Operator | Dec 1993 |
| 28 | DLM Ventures | | Oil & Gas Operator | Dec 2004 |
| 29 | DLM Ventures LLC | | Oil & Gas Operator | Dec 2004 |
| 30 | Doc Oil Corp. | | Oil Operator | Dec 2006 |
| 31 | Dole Enterprises Inc. | | Oil & Gas Operator | Sep 2025 |
| 32 | Dominguez Energy L.P. | | Oil & Gas Operator | Dec 2000 |
| 33 | Dominguez Properties | | Oil & Gas Operator | Dec 1991 |
| 34 | Donald C Slawson Expl Co. Inc | | Oil & Gas Operator | Dec 2020 |
| 35 | Donald Len Barreth | | Oil & Gas Operator | Dec 1991 |
| 36 | Dos Lobos Oil Co. | | Oil Operator | Dec 1999 |
| 37 | Dos Rios Inc. | | Gas Operator | Sep 2025 |
| 38 | Double Barrel Oil Co. | | Oil Operator | Dec 1978 |
| 39 | Douglas W. Baker Trustee | | Oil & Gas Operator | Dec 1993 |
| 40 | Douglas Whitney | | Oil Operator | Dec 2004 |
| 41 | Dow Chemical Co. | | Oil & Gas Operator | Dec 1997 |
| 42 | Drilling & Production Co. | | Oil & Gas Operator | Sep 2025 |
| 43 | Drilling Exploration & Operating Co. Inc. | | Oil & Gas Operator | Sep 2025 |
| 44 | Driltrol | | Oil & Gas Operator | Dec 1984 |
| 45 | Dwayne'S Engineering | | Oil Operator | Aug 2025 |
| 46 | Dynamic Production, Inc. | Fort Worth, TX 76106 | Oil & Gas Operator | Nov 2025 |