| 1 | Talon Development Company | Boerne, TX 78006 | Oil & Gas Operator | Sep 2007 |
| 2 | TDC Engineering, Inc. | Abilene, TX 79604 | Oil & Gas Operator | Dec 2025 |
| 3 | Texaco E & P Inc. | Houston, TX 77099 | Oil & Gas Operator | Dec 2025 |
| 4 | Texas Independent Explor LTD. | Houston, TX 77024 | Oil & Gas Operator | Dec 2025 |
| 5 | Texas Independent Explor., Inc. | Houston, TX 77002 | Oil & Gas Operator | Oct 2002 |
| 6 | Texas Vanguard Oil Company | Austin, TX 78720 | Oil & Gas Operator | Jan 2014 |
| 7 | Texcal Energy (GP) LLC | Denver, CO 80202 | Oil & Gas Operator | Mar 2016 |
| 8 | Torch Operating Company | Houston, TX 77010 | Oil & Gas Operator | Mar 2015 |
| 9 | Total Minatome Corporation | Houston, TX 77210 | Oil & Gas Operator | Dec 1998 |
| 10 | Tradition Resources Oper, LLC | Houston, TX 77002 | Oil & Gas Operator | Jul 2017 |
| 11 | Trailblazer Energy Resources, LLC | Tulsa, OK 74136 | Oil & Gas Operator | Dec 2025 |
| 12 | Tri-Union Development Corp. | Houston, TX 77002 | Oil & Gas Operator | Dec 2025 |
| 13 | Trio Operating Company, Inc. | Wichita Falls, TX 76307 | Oil & Gas Operator | Apr 2006 |
| 14 | Trivista Operating LLC | Giddings, TX 78942 | Oil & Gas Operator | Dec 2025 |