| 1 | T & B Resources | | Oil & Gas Operator | Jul 1990 |
| 2 | Tabco Exploration Inc. | New Orleans, LA 70131 | Oil & Gas Operator | Dec 1998 |
| 3 | Targa Midstream Services LLC | Houston, TX 77002 | Oil Operator | Mar 2023 |
| 4 | Tarpon Oil Of Texas | | Oil & Gas Operator | Aug 1994 |
| 5 | Tee Operating Company | | Oil & Gas Operator | Jun 1989 |
| 6 | Telico Minerals, L.L.C. | | Oil & Gas Operator | Oct 2019 |
| 7 | Tenneco Oil Company | Oklahoma City, OK 73125 | Oil & Gas Operator | Dec 2024 |
| 8 | Tennessee Gas Pipeline Company | Houston, TX 77252 | Oil & Gas Operator | Dec 2011 |
| 9 | Tennessee Gas Pipeline Company, LLC | Houston, TX 77252 | Oil Operator | Dec 2024 |
| 10 | Tensas Exploraton & Production Co LLC | | Oil & Gas Operator | Nov 2009 |
| 11 | Tesla Resources, Inc. | | Oil & Gas Operator | Aug 1996 |
| 12 | Tex/Con Oil & Gas Company | Houston, TX 77074 | Oil & Gas Operator | Feb 2001 |
| 13 | Texaco Inc | Kingfisher, OK 73750 | Oil & Gas Operator | Dec 2017 |
| 14 | Texaco Producing Inc. | Rock Springs, WY 82901 | Oil & Gas Operator | Dec 2000 |
| 15 | Texas Gas Exploration Corp. | | Oil & Gas Operator | Nov 1986 |
| 16 | Texas Pacific Oil Company Inc. | | Oil & Gas Operator | Dec 1980 |
| 17 | Texas Petroleum Investment Company | Houston, TX 77057 | Oil & Gas Operator | Mar 2025 |
| 18 | Texasgulf Inc. | Newgulf, TX 77462 | Oil & Gas Operator | Jul 1994 |
| 19 | The Ballard & Cordell Corp | | Oil & Gas Operator | Feb 1982 |
| 20 | The Meridian Res. & Exp. LLC | | Oil & Gas Operator | Sep 2010 |
| 21 | The Meridian Resource & Exp Co | | Oil & Gas Operator | Dec 2000 |
| 22 | The Southern Louisiana Expl. Company LLC | | Oil & Gas Operator | Nov 2024 |
| 23 | Thomas C. Hoffpauir | | Oil & Gas Operator | Mar 1991 |
| 24 | Tiger Petroleum | | Oil Operator | Sep 2002 |
| 25 | Tipco | Shreveport, LA 71104-3047 | Oil & Gas Operator | May 1988 |
| 26 | Tom Brown Inc | Denver, CO 80202 | Oil & Gas Operator | Dec 2004 |
| 27 | Tom Littlepage Oil Properties | | Oil & Gas Operator | Dec 1984 |
| 28 | Torch Operating Company | Houston, TX 77010 | Oil & Gas Operator | Mar 2015 |
| 29 | Total Minatome Corporation | Houston, TX 77210 | Oil & Gas Operator | Dec 1998 |
| 30 | Trace Operators, Inc. | | Oil & Gas Operator | Nov 2024 |
| 31 | Traillour Oil Co. | | Oil & Gas Operator | Mar 1990 |
| 32 | Tribal Oil Company | | Oil & Gas Operator | Dec 1981 |
| 33 | Triumph Energy, Inc. | Lafayette, LA 70505 | Oil & Gas Operator | Nov 2015 |
| 34 | Txo Production Corp. | Ganado, TX 77962 | Oil & Gas Operator | Aug 2022 |