| 1 | Tag Operating Company, Inc. | Houston, TX 77092 | Oil & Gas Operator | Dec 2024 |
| 2 | Tam2 Squared Operating, LLC | Ranger, TX 76470 | Oil & Gas Operator | Dec 2024 |
| 3 | Tasca Exploration Company | Houston, TX 77257 | Oil & Gas Operator | Jun 2002 |
| 4 | Tejones Operating Corporation | San Antonio, TX 78217 | Oil & Gas Operator | Dec 2024 |
| 5 | Tepee Petroleum Company, Inc. | Houston, TX 77098 | Oil & Gas Operator | Feb 2014 |
| 6 | Tesoro E&P Company, L.P. | San Antonio, TX 78216 | Oil & Gas Operator | Jan 2000 |
| 7 | Tesoro Expl. & Prod. Company | San Antonio, TX 78216 | Gas Operator | Sep 2010 |
| 8 | Texaco E & P Inc | Houston, TX 77099 | Oil & Gas Operator | Dec 2024 |
| 9 | Texas Fuel Company | Galveston, TX 77550 | Oil & Gas Operator | Dec 2024 |
| 10 | Texas Independent Explor LTD. | Houston, TX 77024 | Oil & Gas Operator | Dec 2024 |
| 11 | Texas Independent Explor., Inc. | Houston, TX 77002 | Oil & Gas Operator | Oct 2002 |
| 12 | Texas Valley Oil & Gas, LLC | Hidalgo, TX 78557 | Oil Operator | Dec 2024 |
| 13 | Texas Western Energy Corporation | Portland, TX 78374 | Oil & Gas Operator | Nov 2002 |
| 14 | Texas, Les & Co. | Austin, TX 78746 | Oil & Gas Operator | Dec 2024 |
| 15 | Tharp Operating Company | Houston, TX 77070 | Oil & Gas Operator | Nov 2014 |
| 16 | The Houston Exploration Company | Houston, TX 77002 | Oil & Gas Operator | Apr 2017 |
| 17 | Thorp Petroleum Corporation | Houston, TX 77002 | Oil & Gas Operator | Feb 2014 |
| 18 | Three C Exploration, LLC | Austin, TX 78746 | Oil & Gas Operator | Dec 2024 |
| 19 | Three-C Oil And Gas | Austin, TX 78746 | Oil & Gas Operator | Dec 2024 |
| 20 | Thresher Energy, Inc. | Houston, TX 77060 | Oil & Gas Operator | Dec 2024 |
| 21 | Tidelands Oil Corporation | Crystal City, TX 78839 | Oil & Gas Operator | Aug 2003 |
| 22 | Tiza Energy, Inc. | Austin, TX 78715 | Oil & Gas Operator | Dec 2024 |
| 23 | TNR Petroleum, Inc. | Austin, TX 78747 | Oil & Gas Operator | Sep 1999 |
| 24 | TNT Petroleum Company, Inc. | Corpus Chrsti, TX 78473 | Oil & Gas Operator | Feb 1996 |
| 25 | Toma Oil & Gas, Inc. | Corpus Chrsti, TX 78411 | Oil & Gas Operator | Oct 1997 |
| 26 | Total E&P USA, Inc. | Houston, TX 77210 | Oil & Gas Operator | Nov 2011 |
| 27 | Totalfinaelf E&P USA Inc | Houston, TX 77024 | Oil & Gas Operator | Jul 2007 |
| 28 | Touchstone Resources USA, Inc. | Houston, TX 77002 | Oil & Gas Operator | Oct 2006 |
| 29 | Trans-Pecos Resources, Inc. | Houston, TX 77056 | Oil & Gas Operator | Dec 2024 |
| 30 | Transpacific Energy, LLC | Katy, TX 77450 | Oil & Gas Operator | Dec 2024 |
| 31 | Transtexas Gas Corporation | Houston, TX 77265 | Oil & Gas Operator | Aug 2005 |
| 32 | Trap Rock Oil Company | Cambridge, MA 02138 | Oil & Gas Operator | Nov 2005 |
| 33 | Trap Rock Oil, LTD. | Houston, TX 77027 | Oil & Gas Operator | Dec 2024 |
| 34 | Trek Resources, Inc. | Dallas, TX 75207 | Oil & Gas Operator | Dec 2024 |
| 35 | Tri-C Resources, Inc. | Houston, TX 77024 | Oil & Gas Operator | Aug 2009 |
| 36 | Triad O&G, LLC | Dallas, TX 75225 | Oil & Gas Operator | Dec 2024 |
| 37 | Trinity River Energy Oper, LLC | Houston, TX 77008 | Oil & Gas Operator | May 2018 |
| 38 | True Oil Company | Casper, WY 82602 | Oil & Gas Operator | Aug 2003 |
| 39 | Txco Resources Inc. | San Antonio, TX 78280 | Oil & Gas Operator | Dec 2024 |