| 201 | Tipco | Shreveport, LA 71104-3047 | Oil & Gas Operator | May 1988 |
| 202 | Tipco Operating Co. | Marshall, TX 75671 | Oil & Gas Operator | Jun 2026 |
| 203 | Tipperary Oil & Gas Corporation | Denver, CO 80202 | Oil & Gas Operator | May 2014 |
| 204 | Titan Oil Corp. | | Oil & Gas Operator | Jan 2025 |
| 205 | Tma Production, LLC | | Oil Operator | Dec 2024 |
| 206 | TMR Exploration, Inc. | Bossier City, LA 71171 | Oil & Gas Operator | Sep 2025 |
| 207 | TNC Energy, LLC | Lubbock, TX 79401 | Oil & Gas Operator | Nov 2016 |
| 208 | Toc, Inc. (TN) | | Oil Operator | Apr 1995 |
| 209 | Toce Energy, L.L.C. | | Oil & Gas Operator | Dec 2017 |
| 210 | Toce Oil Company | | Oil & Gas Operator | Dec 2014 |
| 211 | Todd Bertolet | | Gas Operator | Apr 1999 |
| 212 | Todd Oil Corp. Of La. Inc. | | Oil & Gas Operator | Jul 2000 |
| 213 | Todd Oil Production Co | | Oil Operator | Aug 2001 |
| 214 | Tola Production Company | Dallas, TX 75367 | Oil & Gas Operator | Jun 2026 |
| 215 | Tolar Corporation | | Oil & Gas Operator | Sep 1999 |
| 216 | Tolar Energy, L.L.C. | | Oil & Gas Operator | Dec 2001 |
| 217 | Tolbert & Associates | | Oil Operator | Dec 2024 |
| 218 | Tolbert Et Al | | Oil Operator | Jun 2000 |
| 219 | Tolbert Well Service | | Oil Operator | Jan 2025 |
| 220 | Toledo Bend Well Service | | Oil Operator | Aug 2000 |
| 221 | Tom Brown Inc | Denver, CO 80202 | Oil & Gas Operator | Dec 2004 |
| 222 | Tom Littlepage Oil Properties | | Oil & Gas Operator | Dec 1984 |
| 223 | Tom Moore Trustee | | Oil Operator | Apr 1986 |
| 224 | Tom West | | Oil & Gas Operator | Nov 1989 |
| 225 | Tomlinson Oil Co Inc | Great Bend, KS 67530 | Oil & Gas Operator | May 2025 |
| 226 | Tommy A. Paul | | Oil Operator | Oct 2020 |
| 227 | Tommy Joe Jenny | | Gas Operator | Nov 2024 |
| 228 | Topaz Oil Company | Diboll, TX 75941 | Oil & Gas Operator | Apr 1994 |
| 229 | Torch Energy Services, Inc. | Houston, TX 77010 | Oil & Gas Operator | Sep 2011 |
| 230 | Torch Oil & Gas Company | Houston, TX 77010 | Oil & Gas Operator | Aug 1997 |
| 231 | Torch Operating Company | Houston, TX 77010 | Oil & Gas Operator | Mar 2015 |
| 232 | Torch Opr Co-Stone Petr Corp | | Oil & Gas Operator | Jul 1997 |
| 233 | Torrid Energy Company | | Oil & Gas Operator | Jun 1988 |
| 234 | Tortuga Operating Company | Houston, TX 77055 | Oil & Gas Operator | Jun 2026 |
| 235 | Total E&P USA, Inc. | Houston, TX 77210 | Oil & Gas Operator | May 2025 |
| 236 | Total Minatome Corporation | Houston, TX 77210 | Oil & Gas Operator | Dec 1998 |
| 237 | Totalfinaelf E&P USA Inc | Houston, TX 77024 | Oil & Gas Operator | Jul 2007 |
| 238 | Touchstone Properties, Inc. | | Oil Operator | Mar 1988 |
| 239 | Trace Operators, Inc. | | Oil & Gas Operator | Nov 2024 |
| 240 | Tracer Energy, Inc. | Graham, TX 76450 | Oil & Gas Operator | Nov 1998 |
| 241 | Trade & Development Corp | | Oil & Gas Operator | Nov 1996 |
| 242 | Tradestar Energy, Inc. | Hot Springs, AR 71913 | Oil Operator | Feb 2021 |
| 243 | Tradition Resources Oper, LLC | Houston, TX 77002 | Oil & Gas Operator | Jul 2017 |
| 244 | Trafalgar House Oil & Gas Inc | Houston, TX 77002-7346 | Oil & Gas Operator | Jan 1992 |
| 245 | Traillour Oil Co. | | Oil & Gas Operator | Mar 1990 |
| 246 | Trans Ocean Oil, Inc. | | Oil & Gas Operator | Sep 1980 |
| 247 | Trans-Gulf Petroleum Corp | | Oil & Gas Operator | Sep 1999 |
| 248 | Trans-Pacific Oil & Gas Inc. | | Oil & Gas Operator | Mar 1982 |
| 249 | Trans-Sabine Pipeline Corp | | Oil Operator | Mar 2009 |
| 250 | Trans-Western Exploration Inc | Dallas, TX 75240 | Oil & Gas Operator | Mar 1993 |
| 251 | Transamerican Energy/Toce Oil | | Oil & Gas Operator | Dec 1994 |
| 252 | Transamerican-Swepi-Toce Oil | | Oil & Gas Operator | Apr 1990 |
| 253 | Transco Exploration Company | | Oil & Gas Operator | Jul 1989 |
| 254 | Transcontinental Gas P/L Corp. | | Oil & Gas Operator | Dec 2009 |
| 255 | Transcontinental Gas Pipeline Co LLC | | Oil Operator | Jan 2025 |
| 256 | Transcontinental Oil Corp. | | Oil & Gas Operator | Sep 1985 |
| 257 | Transfuel Resources Co | Houston, TX 77215 | Oil & Gas Operator | Aug 2013 |
| 258 | Transtexas Gas Corporation | Houston, TX 77265 | Oil & Gas Operator | Aug 2005 |
| 259 | Transworld Expl. & Prod., Inc. | | Oil & Gas Operator | Mar 2004 |
| 260 | Traver Oil & Gas Corporation | | Oil & Gas Operator | Sep 2000 |
| 261 | Traver Oil Company | | Oil & Gas Operator | Sep 2000 |
| 262 | Traver-Patterson Petroleum Inc | | Oil & Gas Operator | May 1990 |
| 263 | Travis E. Duren | | Oil Operator | Jul 1995 |
| 264 | Trebole Operating Company | | Oil Operator | Jul 1979 |
| 265 | Tredegar Properties, Inc. | | Oil Operator | Jun 1990 |
| 266 | Trek Resources, Inc. | Dallas, TX 75207 | Oil & Gas Operator | Jun 2026 |
| 267 | Trendsetter Production Co, Inc | | Oil & Gas Operator | Jul 2008 |
| 268 | Tri Investment Company | | Oil Operator | Mar 1980 |
| 269 | Tri-C Resources, Inc. | Houston, TX 77024 | Oil & Gas Operator | Aug 2009 |
| 270 | Tri-C Resources, LLC | Houston, TX 77024 | Oil & Gas Operator | Jun 2026 |
| 271 | Tri-Par Exploration, Inc. | | Oil Operator | Oct 2001 |
| 272 | Tri-Production Company | | Oil Operator | Apr 1994 |
| 273 | Tri-State Exploration & Prod Inc | Marshall, TX 75671 | Oil & Gas Operator | Aug 2003 |
| 274 | Tri-State Sales & Production | Rodessa, LA 71069 | Oil & Gas Operator | Dec 2008 |
| 275 | Tri-Union Development Corp. | Houston, TX 77002 | Oil & Gas Operator | Jun 2026 |
| 276 | Triad Energy Corp Of Texas | Houston, TX 77057-2696 | Oil & Gas Operator | Sep 2014 |
| 277 | Triad Resources Inc | Spring, TX 77389 | Oil & Gas Operator | Dec 2020 |
| 278 | Triangle Oil & G G Cornwell | | Oil & Gas Operator | Nov 1981 |
| 279 | Triangle Oil Of Hosston | | Oil Operator | Jul 2014 |
| 280 | Triangle Oil Producers Inc | | Oil & Gas Operator | Jun 1998 |
| 281 | Tribal Oil Company | | Oil & Gas Operator | Dec 1981 |
| 282 | Tricentrol Resources Inc | Englewood, CO 80111 | Oil & Gas Operator | Jun 1984 |
| 283 | Trich Production, Inc. | Longview, TX 75606 | Oil & Gas Operator | Jan 2025 |
| 284 | Trichel Contracting Company | | Oil & Gas Operator | Sep 1987 |
| 285 | Trickle Down Oil, Inc. | | Oil & Gas Operator | Feb 2016 |
| 286 | Trico Energy Corporation | | Oil Operator | May 1984 |
| 287 | Trico Oil & Gas Inc. | Kilgore, TX 75662 | Oil & Gas Operator | Jun 2026 |
| 288 | Trident Oil & Gas Corp. | | Oil & Gas Operator | Sep 2000 |
| 289 | Trigon Exploration, Inc. | | Oil & Gas Operator | Jan 1999 |
| 290 | Trinidad Petroleum Corporation | | Oil & Gas Operator | Apr 1990 |
| 291 | Trinity Operating (Usg), LLC | Houston, TX 77002 | Oil & Gas Operator | Jun 2026 |
| 292 | Trinity Resources, Inc. | Houston, TX 77277 | Oil & Gas Operator | May 2020 |
| 293 | Trinity River Energy Oper, LLC | Houston, TX 77008 | Oil & Gas Operator | May 2018 |
| 294 | Triple J Investments Inc | Longview, TX 75606 | Oil & Gas Operator | Feb 2023 |
| 295 | Triple J Oil Co. | Pampa, TX 79065 | Oil & Gas Operator | Aug 1996 |
| 296 | Triple L Oil Company | Corpus Christ, TX 78469 | Oil & Gas Operator | Jan 1998 |
| 297 | Triple L Operating Company LLC | Kilgore, TX 75663 | Oil Operator | Jun 2026 |
| 298 | Triple S Oil Company | | Oil & Gas Operator | Feb 1979 |
| 299 | Tripower Resources, Inc. | Ardmore, OK 73402 | Oil & Gas Operator | Mar 2020 |
| 300 | Tristar Energy 1 | | Oil Operator | Sep 1987 |