| 1 | T & G Oil, Inc. | White Oak, TX 75693 | Oil & Gas Operator | Dec 2010 |
| 2 | T & T Production Co. | Victoria, TX 77902 | Oil & Gas Operator | Feb 1995 |
| 3 | T-C Oil Company, LLC | Refugio, TX 78377 | Oil & Gas Operator | Oct 2025 |
| 4 | T.D. Operating Company, Inc. | New Braunfels, TX 78130 | Oil & Gas Operator | Nov 1999 |
| 5 | Talon Development Company | Boerne, TX 78006 | Oil & Gas Operator | Sep 2007 |
| 6 | Tamarack Petroleum Company, Inc. | Midland, TX 79701 | Oil & Gas Operator | Oct 2025 |
| 7 | TC Oil And Gas, LLC | Denton, TX 76205 | Oil Operator | Oct 2025 |
| 8 | TDC Engineering, Inc. | Abilene, TX 79604 | Oil & Gas Operator | Oct 2025 |
| 9 | TDX Energy, LLC | Shreveport, LA 71101 | Oil & Gas Operator | Dec 2024 |
| 10 | Teal Operating, LLC | Dallas, TX 75225 | Oil & Gas Operator | Oct 2021 |
| 11 | Tend Oil Inc. | Tyler, TX 75703 | Oil & Gas Operator | Jul 1995 |
| 12 | Tensas Delta Explo. Co., LLC | Shreveport, LA 71101 | Oil & Gas Operator | Dec 2011 |
| 13 | Tepee Petroleum Company, Inc. | Houston, TX 77098 | Oil & Gas Operator | Feb 2014 |
| 14 | Texaco E & P Inc | Houston, TX 77099 | Oil & Gas Operator | Oct 2025 |
| 15 | Texakoma E & P, LLC | Plano, TX 75024 | Oil & Gas Operator | Oct 2025 |
| 16 | Texana Operating Company | Houston, TX 77090 | Oil & Gas Operator | Oct 2025 |
| 17 | Texas Crude Energy, Inc. | Houston, TX 77256 | Oil & Gas Operator | Oct 2012 |
| 18 | Texas Gulf Gas Corporation | Fayetteville, TX 78940 | Oil & Gas Operator | Jun 2005 |
| 19 | Texas Independent Explor LTD. | Houston, TX 77024 | Oil & Gas Operator | Oct 2025 |
| 20 | Texas Independent Explor., Inc. | Houston, TX 77002 | Oil & Gas Operator | Oct 2002 |
| 21 | Texas Onshore Energy, Inc. | Austin, TX 78704 | Oil & Gas Operator | Oct 2025 |
| 22 | Texcal Energy (GP) LLC | Denver, CO 80202 | Oil & Gas Operator | Mar 2016 |
| 23 | Texron Operating, LLC | Bulverde, TX 78163 | Oil & Gas Operator | Oct 2025 |
| 24 | Tgo Operating, LLC | Midland, TX 79705 | Oil & Gas Operator | Dec 2008 |
| 25 | Thorp Petroleum Corporation | Houston, TX 77002 | Oil & Gas Operator | Feb 2014 |
| 26 | Tidal Petroleum, Inc. | Schertz, TX 78154 | Oil & Gas Operator | Oct 2025 |
| 27 | TMR Exploration, Inc. | Bossier City, LA 71171 | Oil & Gas Operator | Oct 2025 |
| 28 | Torch Operating Company | Houston, TX 77010 | Oil & Gas Operator | Mar 2015 |
| 29 | Transtexas Gas Corporation | Houston, TX 77265 | Oil & Gas Operator | Aug 2005 |
| 30 | Trek Resources, Inc. | Dallas, TX 75207 | Oil & Gas Operator | Oct 2025 |
| 31 | Tri-C Resources, Inc. | Houston, TX 77024 | Oil & Gas Operator | Aug 2009 |
| 32 | Tri-Union Development Corp. | Houston, TX 77002 | Oil & Gas Operator | Oct 2025 |
| 33 | Triad Energy Corporation | Houston, TX 77057 | Oil & Gas Operator | Oct 2011 |
| 34 | Triangle Development Co | Mahtomedi, MN 55115 | Gas Operator | Feb 1982 |
| 35 | Trinity Resources, Inc. | Houston, TX 77277 | Oil & Gas Operator | May 2020 |
| 36 | Trio Consulting & Management,LLC | Wichita Falls, TX 76307 | Oil & Gas Operator | Oct 2025 |
| 37 | Trio Operating Company, Inc. | Wichita Falls, TX 76307 | Oil & Gas Operator | Apr 2006 |
| 38 | Trio Production Company, LLC | Stephens, AR 71764 | Oil Operator | Jan 2025 |
| 39 | Triple J Investments Inc | Longview, TX 75606 | Oil & Gas Operator | Feb 2023 |
| 40 | Triton Oil & Gas Corp. | Houston, TX 77002 | Oil & Gas Operator | Nov 2014 |
| 41 | Tsar Energy, LLC | Dallas, TX 75205 | Oil & Gas Operator | Oct 2025 |
| 42 | Tucker Operating Co., Inc. | Victoria, TX 77903 | Oil & Gas Operator | Oct 2025 |