| 1 | T - C Oil Company | Refugio, TX 78377 | Oil & Gas Operator | Jan 2012 |
| 2 | T-C Oil Company, LLC | Refugio, TX 78377 | Oil & Gas Operator | Oct 2025 |
| 3 | T.D. Operating Company, Inc. | New Braunfels, TX 78130 | Oil & Gas Operator | Nov 1999 |
| 4 | Talisman Energy USA Inc. | The Woodlands, TX 77381 | Oil & Gas Operator | May 2016 |
| 5 | Talon Development Company | Boerne, TX 78006 | Oil & Gas Operator | Sep 2007 |
| 6 | Tare Resources, LLC | Corpus Chrsti, TX 78426 | Oil & Gas Operator | Oct 2025 |
| 7 | Tasca Exploration Company | Houston, TX 77257 | Oil & Gas Operator | Jun 2002 |
| 8 | TC Oil And Gas, LLC | Denton, TX 76205 | Oil Operator | Oct 2025 |
| 9 | Tepee Petroleum Company, Inc. | Houston, TX 77098 | Oil & Gas Operator | Feb 2014 |
| 10 | Texacal, Inc. | Newport Beach, CA 92660 | Oil & Gas Operator | Oct 2025 |
| 11 | Texaco E & P Inc | Houston, TX 77099 | Oil & Gas Operator | Oct 2025 |
| 12 | Texas Independent Explor., Inc. | Houston, TX 77002 | Oil & Gas Operator | Oct 2002 |
| 13 | Texas Southern Petroleum Corp. | Corpus Chrsti, TX 78410 | Oil & Gas Operator | Oct 2025 |
| 14 | Texas Sunset Energy And Ent Inc | Victoria, TX 77904 | Oil Operator | Aug 2003 |
| 15 | Texas, Les & Co. | Austin, TX 78746 | Oil & Gas Operator | Oct 2025 |
| 16 | Texron Operating, LLC | Bulverde, TX 78163 | Oil & Gas Operator | Oct 2025 |
| 17 | Thunder Oil & Gas, LLC | Ardmore, OK 73402 | Oil & Gas Operator | Jun 2025 |
| 18 | Tidal Petroleum, Inc. | Schertz, TX 78154 | Oil & Gas Operator | Oct 2025 |
| 19 | Tidewater Minerals Corporation | Orange Grove, TX 78372 | Oil & Gas Operator | Oct 2025 |
| 20 | Torch Operating Company | Houston, TX 77010 | Oil & Gas Operator | Mar 2015 |
| 21 | Trans-Pecos Resources, Inc. | Houston, TX 77056 | Oil & Gas Operator | Oct 2025 |
| 22 | Transfuel Resources Co | Houston, TX 77215 | Oil & Gas Operator | Aug 2013 |
| 23 | Trident Corporation | Woodsboro, TX 78393 | Oil & Gas Operator | Oct 2025 |
| 24 | Trinity River Energy Oper, LLC | Houston, TX 77008 | Oil & Gas Operator | May 2018 |
| 25 | Triple L Oil Company | Corpus Chrsti, TX 78469 | Oil & Gas Operator | Jan 1998 |
| 26 | Tschoepe, Arthur J. | Leakey, TX 78873 | Oil & Gas Operator | Jun 2001 |
| 27 | Tsoco | Tuleta, TX 78162 | Oil & Gas Operator | Apr 2017 |
| 28 | Tsoco & W. M. Null | Pettus, TX 78146 | Oil & Gas Operator | Aug 2002 |
| 29 | Tucker Petroleum, Inc. | Corpus Chrsti, TX 78468 | Oil & Gas Operator | Oct 2025 |
| 30 | TX Petroleum Company | Corpus Chrsti, TX 78412 | Oil & Gas Operator | Apr 1996 |