| 1 | D & H Production, Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Mar 2024 |
| 2 | D-S-B Properties, Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Sep 2014 |
| 3 | D-S-B Properties, LLC | Kilgore, TX 75663 | Oil & Gas Operator | Oct 2025 |
| 4 | Daco Oil | Joinerville, TX 75658 | Oil & Gas Operator | Aug 2019 |
| 5 | Dal-Long Oil Company | Longview, TX 75608 | Oil Operator | Feb 2001 |
| 6 | Dalen Resources Oil & Gas Co. | Dallas, TX 75206 | Oil & Gas Operator | Jun 2010 |
| 7 | Dallas Production Company LLC | Dallas, TX 75206 | Oil & Gas Operator | Oct 2025 |
| 8 | Dallas Production, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Mar 2021 |
| 9 | Danmark Energy Services, Inc. | White Oak, TX 75693 | Oil & Gas Operator | Apr 2021 |
| 10 | Dearing, Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Mar 2021 |
| 11 | Deco | Kilgore, TX 75662 | Oil & Gas Operator | Jan 1999 |
| 12 | Delek Energy Systems Us Inc | Denver, CO 80202 | Oil & Gas Operator | Oct 2011 |
| 13 | Denovo Oil & Gas, Inc. | Houston, TX 77210 | Oil & Gas Operator | May 1995 |
| 14 | Desana Development Corporation | Midland, TX 79701 | Oil & Gas Operator | Oct 2025 |
| 15 | Discovery Natural Resources LLC | Denver, CO 80202 | Oil & Gas Operator | Oct 2025 |
| 16 | Diversified Production LLC | Keithville, LA 71047 | Oil & Gas Operator | Oct 2025 |
| 17 | Donnell Pipe & Supply Co/TX Corp | Kilgore, TX 75663 | Oil & Gas Operator | Mar 2008 |
| 18 | Dorfman Production Company | Beloit, OH 44609 | Oil & Gas Operator | Oct 2025 |
| 19 | Dunbar, Ron, Inc. | Longview, TX 75606 | Oil & Gas Operator | Jan 2012 |
| 20 | Dyersdale Energy, L.P. | Kilgore, TX 75663 | Oil & Gas Operator | Oct 2025 |
| 21 | Dyersdale Production Co, Inc. | Houston, TX 77019 | Oil & Gas Operator | Oct 2025 |