| 1 | D & B Oil Company | Graham, TX 76450 | Oil & Gas Operator | Dec 2025 |
| 2 | D & D Contract Pumping Inc | Casper, WY 82604 | Oil Operator | Nov 2025 |
| 3 | D & J Oil Company | Kermit, TX 79745 | Oil & Gas Operator | Dec 2025 |
| 4 | D K Cook Heirs LLC | Houston, TX 77002 | Oil & Gas Operator | Dec 2011 |
| 5 | D90 Energy, LLC | Houston, TX 77024 | Oil & Gas Operator | Dec 2025 |
| 6 | Dahill Murray P | Casper, WY 82601 | Oil & Gas Operator | Jun 2007 |
| 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 | Darrah John Jay Jr | Wichita, KS 67201 | Oil & Gas Operator | Sep 2025 |
| 10 | Daube Company The | Ardmore, OK 73401 | Oil & Gas Operator | Sep 2025 |
| 11 | Davey Corporation | Golden, CO 80401 | Oil & Gas Operator | Oct 2025 |
| 12 | Davis & Tharel | | Oil & Gas Operator | Dec 1988 |
| 13 | Davis Bobby J | Upton, WY 82730 | Oil & Gas Operator | Oct 1989 |
| 14 | Davis Exploration | | Oil Operator | Dec 2007 |
| 15 | Davis Oil Company | Denver, CO 80202 | Oil & Gas Operator | Jun 1988 |
| 16 | Davis Petroleum Corp. | Houston, TX 77027 | Oil & Gas Operator | Dec 2025 |
| 17 | Dawson Resources Inc | Franktown, CO 80116 | Oil & Gas Operator | Mar 2015 |
| 18 | DCD Inc | Gillette, WY 82716 | Oil & Gas Operator | Aug 2003 |
| 19 | Debord Oil Producers | Lincoln, NE 68503 | Oil Operator | Dec 1998 |
| 20 | Deca Energy Corporation | | Oil & Gas Operator | Aug 1986 |
| 21 | Decalta International Corp | Denver, CO 80202 | Oil & Gas Operator | Mar 2015 |
| 22 | Degaugh Well Service Inc | | Oil Operator | Jul 1989 |
| 23 | Dekalb Energy Company | Oklahoma City, OK 73134 | Oil & Gas Operator | Oct 1996 |
| 24 | Delta Exploration Company Inc | Denver, CO 80202 | Oil & Gas Operator | Dec 2025 |
| 25 | Denbury Onshore, LLC | Plano, TX 75024 | Oil & Gas Operator | Dec 2025 |
| 26 | Department Of Energy | Casper, WY 82601 | Oil & Gas Operator | Jan 2015 |
| 27 | Deuel Arch W | | Oil & Gas Operator | Aug 1995 |
| 28 | Devon Energy Operating Corp | Oklahoma City, OK 73102 | Oil & Gas Operator | Apr 2013 |
| 29 | Devon Energy Production Company, L.P. | Oklahoma City, OK 73102 | Oil & Gas Operator | Dec 2025 |
| 30 | Devon SFS Operating Inc | Oklahoma City, OK 73102 | Oil & Gas Operator | Mar 2008 |
| 31 | Diamond B Industries Inc | Belle Fourche, SD 57717 | Oil & Gas Operator | Apr 2010 |
| 32 | Diamond Oil & Gas LLC | Casper, WY 82604 | Oil & Gas Operator | Oct 2025 |
| 33 | Diamondback Oil Partners LLP | Arvada, CO 80004 | Oil & Gas Operator | Sep 2016 |
| 34 | Diasu Oil & Gas Co., Inc. | Houston, TX 77002 | Oil & Gas Operator | Mar 2016 |
| 35 | Dietrich Resources Corporation | | Oil & Gas Operator | Jun 2007 |
| 36 | Discovery Oil LTD | Los Angeles, CA 90067 | Oil & Gas Operator | Jan 1993 |
| 37 | DJ Resources Inc | Bowie, TX 76230 | Oil & Gas Operator | Nov 2017 |
| 38 | DKM Resources, Inc. | Tulsa, OK 74136 | Oil & Gas Operator | Sep 2011 |
| 39 | DNR Oil And Gas, Inc. | Englewood, CO 80155 | Oil & Gas Operator | Oct 2025 |
| 40 | Dol Resources Inc | Rowlett, TX 75088 | Oil & Gas Operator | Oct 2025 |
| 41 | Dolezal George Jr | Littleton, CO 80163 | Oil & Gas Operator | Sep 2006 |
| 42 | Dome Petroleum Corp | Denver, CO 80202 | Oil & Gas Operator | Dec 2016 |
| 43 | Dominion Exploration & Production Inc | Houston, TX 77060 | Oil & Gas Operator | Apr 2015 |
| 44 | Dominion Oklahoma Texas Expl & Prod Inc | Oklahoma City, OK 73134 | Oil & Gas Operator | Aug 2013 |
| 45 | Duer Wagner & Company | Fort Worth, TX 76102 | Oil & Gas Operator | Dec 1998 |
| 46 | Dugan Production Corp | Farmington, NM 87499 | Oil & Gas Operator | Sep 2025 |
| 47 | Duncan Energy Company | Denver, CO 80202 | Oil & Gas Operator | Mar 2008 |
| 48 | Duncan Oil Inc | Denver, CO 80210 | Oil & Gas Operator | Jun 2016 |
| 49 | Dyco Petroleum Corporation | Tulsa, OK 74103 | Oil & Gas Operator | Mar 2015 |
| 50 | Dyer J G | | Oil & Gas Operator | May 1985 |