| 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 | Dale Operating Company | Dallas, TX 75201 | Oil & Gas Operator | Oct 2025 |
| 6 | Dalen Resources Oil & Gas Co. | Dallas, TX 75206 | Oil & Gas Operator | Jun 2010 |
| 7 | Dalf Energy LLC | Pampa, TX 79066 | Oil & Gas Operator | Oct 2025 |
| 8 | Dallas Petroleum Group, LLC | Dallas, TX 75379 | Oil & Gas Operator | Oct 2025 |
| 9 | Dallas Production, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Mar 2021 |
| 10 | Danmark Energy Services, Inc. | White Oak, TX 75693 | Oil & Gas Operator | Apr 2021 |
| 11 | Davis Oil & Gas, LLC | Shreveport, LA 71101 | Oil & Gas Operator | Jun 2011 |
| 12 | Dearing, Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Mar 2021 |
| 13 | Delek Energy Systems Us Inc | Denver, CO 80202 | Oil & Gas Operator | Oct 2011 |
| 14 | Delta Exploration Company Inc | Denver, CO 80202 | Oil & Gas Operator | Oct 2025 |
| 15 | Desana Development Corporation | Midland, TX 79701 | Oil & Gas Operator | Oct 2025 |
| 16 | Devon Energy Production Company LP | Oklahoma City, OK 73102 | Oil & Gas Operator | Oct 2025 |
| 17 | Devon Louisiana Corporation | Houston, TX 77002 | Oil & Gas Operator | Oct 2019 |
| 18 | Diamond Energy, Inc. | Sherman, TX 75091 | Oil & Gas Operator | Oct 2025 |
| 19 | Diamond S Energy Company | Fort Worth, TX 76132 | Oil & Gas Operator | Oct 2025 |
| 20 | Diversified Production LLC | Keithville, LA 71047 | Oil & Gas Operator | Oct 2025 |
| 21 | DNR Oil And Gas, Inc. | Englewood, CO 80155 | Oil & Gas Operator | Aug 2025 |
| 22 | Dominion Exploration & Production Inc | Houston, TX 77060 | Oil & Gas Operator | Apr 2015 |
| 23 | Donnell Pipe & Supply Co/TX Corp | Kilgore, TX 75663 | Oil & Gas Operator | Mar 2008 |
| 24 | Dorado Operating Inc. | Dallas, TX 75225 | Oil & Gas Operator | Apr 2011 |
| 25 | Dowden, T. L. | Henderson, TX 75652 | Oil & Gas Operator | Oct 2025 |
| 26 | DPMP Energy LLC | Prosper, TX 75078 | Oil & Gas Operator | Dec 2023 |
| 27 | Dunbar, Ron, Inc. | Longview, TX 75606 | Oil & Gas Operator | Jan 2012 |
| 28 | Durango Resources Corp. | Houston, TX 77043 | Oil & Gas Operator | Oct 2025 |
| 29 | Dyersdale Energy, L.P. | Kilgore, TX 75663 | Oil & Gas Operator | Oct 2025 |