| 1 | D-Mil Production Inc | Argyle, TX 76226 | Oil & Gas Operator | Feb 2026 |
| 2 | Dale Operating Company | Dallas, TX 75207 | Oil & Gas Operator | Feb 2026 |
| 3 | Dalen Resources Oil & Gas Co | Dallas, TX 75206 | Oil & Gas Operator | Jun 2010 |
| 4 | Dartex Energy Corporation | Austin, TX 78731 | Oil & Gas Operator | Feb 2026 |
| 5 | Daystar Operating Company, LLC | Austin, TX 78750 | Oil & Gas Operator | Apr 2008 |
| 6 | Dedica Energy Corporation | Mattoon, IL 61938 | Oil & Gas Operator | Mar 2008 |
| 7 | Delaware Davis Petroleum Corp. | Houston, TX 77056 | Oil & Gas Operator | Jan 2000 |
| 8 | Denali Oil & Gas Management LLC | Houston, TX 77060 | Oil & Gas Operator | Dec 2012 |
| 9 | Devon Energy Corp (Nevada) | Oklahoma City, OK 73102 | Oil & Gas Operator | Feb 2017 |
| 10 | Devon Energy Operating Co., L.P. | Oklahoma City, OK 73102 | Oil & Gas Operator | Jun 2009 |
| 11 | Devon Energy Production Company, L.P. | Oklahoma City, OK 73102 | Oil & Gas Operator | Feb 2026 |
| 12 | Dewbre Petroleum Corporation | Corpus Chrsti, TX 78404 | Oil & Gas Operator | Feb 2026 |
| 13 | Diamond Operating, LLC | Wichita Falls, TX 76308 | Oil & Gas Operator | Aug 2010 |
| 14 | DJ Exploration, Inc. | San Antonio, TX 78257 | Oil & Gas Operator | Feb 2026 |
| 15 | Dominion Minerals Corporation | Houston, TX 77014 | Oil & Gas Operator | Nov 2009 |
| 16 | Dominion Oklahoma Texas E&P, Inc | Richmond, VA 23219 | Oil & Gas Operator | Sep 2018 |
| 17 | Dorado Oil Company | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Oct 2013 |
| 18 | Double Play Oil & Gas, Inc | Portland, TX 78374 | Oil & Gas Operator | Feb 2026 |
| 19 | Dreyfus, Louis Natural Gas Corp | Oklahoma City, OK 73134 | Oil & Gas Operator | Nov 2001 |
| 20 | Dynamic Production, Inc. | Fort Worth, TX 76102 | Oil & Gas Operator | Feb 2026 |