| 1 | Tabco Exploration Inc. | New Orleans, LA 70131 | Oil & Gas Operator | Dec 1998 |
| 2 | Taylor Energy Co. | | Oil & Gas Operator | May 1991 |
| 3 | Tee Operating Company | | Oil & Gas Operator | Jun 1989 |
| 4 | Terra Resources, Inc. | Casper, WY 82601 | Oil & Gas Operator | Jun 1990 |
| 5 | Tesla Resources, Inc. | | Oil & Gas Operator | Aug 1996 |
| 6 | Texaco E & P Inc | Houston, TX 77099 | Oil & Gas Operator | Oct 2025 |
| 7 | Texaco Inc | Kingfisher, OK 73750 | Oil & Gas Operator | Dec 2017 |
| 8 | Texas Crude Exploration, Inc. | Fort Worth, TX 76116 | Oil & Gas Operator | Aug 1992 |
| 9 | Texas Crude, Inc. | Houston, TX 77256 | Oil & Gas Operator | Oct 1995 |
| 10 | Texas Gas Transmission Corp. | | Oil Operator | Aug 2003 |
| 11 | Texas Petroleum Investment Company | Houston, TX 77057 | Oil & Gas Operator | Oct 2025 |
| 12 | The Meridian Res. & Exp. LLC | | Oil & Gas Operator | Sep 2010 |
| 13 | The Meridian Resource & Exp Co | | Oil & Gas Operator | Dec 2000 |
| 14 | The Stone Oil Corporation | | Oil & Gas Operator | May 1985 |
| 15 | The WM G Helis Company, L.L.C. | | Oil & Gas Operator | Nov 2003 |
| 16 | Thrall Texas Oil, LLC | | Oil & Gas Operator | Jan 2025 |
| 17 | Tiger Petroleum | | Oil Operator | Sep 2002 |
| 18 | Toce Oil Company | | Oil & Gas Operator | Dec 2014 |
| 19 | Torch Operating Company | Houston, TX 77010 | Oil & Gas Operator | Mar 2015 |
| 20 | Transco Exploration Company | | Oil & Gas Operator | Jul 1989 |
| 21 | Transfuel Resources Co | Houston, TX 77215 | Oil & Gas Operator | Aug 2013 |
| 22 | Triton Oil & Gas Corp. | Houston, TX 77002 | Oil & Gas Operator | Nov 2014 |
| 23 | TXP Operating Company | | Oil & Gas Operator | Jul 1992 |