| 1 | T-M Well Service, L.L.C. | Jefferson, TX 75657 | Oil & Gas Operator | Dec 2024 |
| 2 | T. C. Morrow Oil Co. | | Oil & Gas Operator | Apr 1991 |
| 3 | T. L. James & Co., Inc. | | Oil & Gas Operator | Oct 1992 |
| 4 | T. M. Hopkins | | Oil & Gas Operator | Aug 2007 |
| 5 | Talco Midstream Assets, LTD. | | Oil Operator | May 2017 |
| 6 | Target Oil & Gas, Inc. | | Oil & Gas Operator | Nov 2011 |
| 7 | Tatco, Inc. | | Oil & Gas Operator | May 1991 |
| 8 | TD & Associates, Inc. | | Oil & Gas Operator | Jun 1998 |
| 9 | Teal Petroleum Co. | | Oil & Gas Operator | Sep 1978 |
| 10 | Tellurian Operating LLC | | Oil & Gas Operator | Jun 2024 |
| 11 | Tenneco Oil Company | Oklahoma City, OK 73125 | Oil & Gas Operator | Jul 2025 |
| 12 | Tennessee Gas Pipeline Company, LLC | Houston, TX 77002 | Oil Operator | Dec 2024 |
| 13 | Tepee Petroleum Company, Inc. | Houston, TX 77098 | Oil & Gas Operator | Feb 2014 |
| 14 | Terra Resources, Inc. | Casper, WY 82601 | Oil & Gas Operator | Jun 1990 |
| 15 | Terral D Hinds | | Oil Operator | Mar 2012 |
| 16 | Tex/Con Oil & Gas Company | Houston, TX 77074 | Oil & Gas Operator | Feb 2001 |
| 17 | Texaco Producing Inc. | Rock Springs, WY 82901 | Oil & Gas Operator | Dec 2000 |
| 18 | Texas General Petroleum Corp | | Oil & Gas Operator | Aug 1984 |
| 19 | Texas Oil & Gas Corporation | Dallas, TX 75201 | Oil & Gas Operator | Feb 2001 |
| 20 | The Goro Corporation | | Oil & Gas Operator | Jul 1978 |
| 21 | The Hunter Company, Inc. | | Oil & Gas Operator | Sep 1985 |
| 22 | The Romanoff Corporation | | Oil & Gas Operator | Nov 1989 |
| 23 | Thornton & Brooks, Inc. | | Oil & Gas Operator | Oct 1990 |
| 24 | Tide West Oil Company | Tulsa, OK 74136 | Oil & Gas Operator | Mar 2021 |
| 25 | TMR Exploration, Inc. | Bossier City, LA 71171 | Oil & Gas Operator | Oct 2025 |
| 26 | Tola Production Company | Dallas, TX 75367 | Oil & Gas Operator | Oct 2025 |
| 27 | Torch Operating Company | Houston, TX 77010 | Oil & Gas Operator | Mar 2015 |
| 28 | Trans-Gulf Petroleum Corp | | Oil & Gas Operator | Sep 1999 |
| 29 | Trans-Pacific Oil & Gas Inc. | | Oil & Gas Operator | Mar 1982 |
| 30 | Transco Exploration Company | | Oil & Gas Operator | Jul 1989 |
| 31 | Tri-Par Exploration, Inc. | | Oil Operator | Oct 2001 |
| 32 | Trinity River Energy Oper, LLC | Houston, TX 77008 | Oil & Gas Operator | May 2018 |
| 33 | Tristar Energy 1 | | Oil Operator | Sep 1987 |
| 34 | Txo Production Corp. | Ganado, TX 77962 | Oil & Gas Operator | Aug 2022 |