| 201 | DKW Energy, Inc. | Sherman Oaks, CA 91403 | Oil & Gas Operator | Dec 2025 |
| 202 | DML Exploration, Inc. | San Antonio, TX 78217 | Oil & Gas Operator | Dec 2025 |
| 203 | Dogwood Operating Company, Inc. | Houston, TX 77069 | Oil & Gas Operator | Dec 2025 |
| 204 | Dolphin Petroleum | Alice, TX 78333 | Oil & Gas Operator | Jun 2008 |
| 205 | Dominion Exploration & Production Inc | Houston, TX 77060 | Oil & Gas Operator | Apr 2015 |
| 206 | Dominion Oklahoma Texas E&P, Inc | Richmond, VA 23219 | Oil & Gas Operator | Sep 2018 |
| 207 | Donna-Lynne Oil Co. | George West, TX 78022 | Oil & Gas Operator | Jun 2018 |
| 208 | Dorado Oil Company | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Oct 2013 |
| 209 | Double Play Oil & Gas, Inc | Portland, TX 78374 | Oil & Gas Operator | Dec 2025 |
| 210 | Dreyfus, Louis Natural Gas Corp | Oklahoma City, OK 73134 | Oil & Gas Operator | Nov 2001 |
| 211 | Drillers Energy Search, Inc | Denver, CO 80202 | Oil & Gas Operator | Aug 1996 |
| 212 | Dugger, Glenn | Alice, TX 78332 | Oil & Gas Operator | Nov 2013 |
| 213 | Dunigan Petroleum, Inc. | Dallas, TX 75201 | Oil & Gas Operator | Aug 2003 |
| 214 | Duster Production, Inc. | Refugio, TX 78377 | Oil & Gas Operator | Oct 2011 |
| 215 | Duval Gas Gathering Corporation | Austin, TX 78711 | Oil & Gas Operator | Dec 2025 |
| 216 | Dynamic Production, Inc. | Fort Worth, TX 76102 | Oil & Gas Operator | Dec 2025 |
| 217 | Edge Petroleum Oper. Co., Inc. | Houston, TX 77042 | Oil & Gas Operator | Nov 2010 |
| 218 | Eex Corporation | Houston, TX 77060 | Oil & Gas Operator | Feb 2000 |
| 219 | Eex E&P Company, L.P. | Houston, TX 77060 | Oil & Gas Operator | Jul 2003 |
| 220 | Eex Operating, L.P. | Houston, TX 77060 | Oil & Gas Operator | Jul 2003 |
| 221 | El Campo Operating, LLC | Dallas, TX 75206 | Oil & Gas Operator | Feb 2011 |
| 222 | El Dorado Resources Inc. | Waco, TX 76710 | Oil & Gas Operator | Oct 2009 |
| 223 | El Mesteno Energy LLC | Three Rivers, TX 78071 | Oil Operator | Dec 2025 |
| 224 | El Paso E&P Company, L.P. | Houston, TX 77002 | Oil & Gas Operator | Mar 2013 |
| 225 | El Paso Production Company | Houston, TX 77002 | Oil & Gas Operator | Mar 2016 |
| 226 | El Paso Production Oil & Gas Co. | Houston, TX 77252 | Oil & Gas Operator | Dec 2025 |
| 227 | Eland Energy Inc | Dallas, TX 75248 | Oil & Gas Operator | Nov 2025 |
| 228 | Eldon Oil Co. | Three Rivers, TX 78071 | Oil & Gas Operator | Dec 2025 |
| 229 | Elliott Oil & Gas Company | The Woodlands, TX 77380 | Oil & Gas Operator | Sep 2006 |
| 230 | Ellsworth, H. P. O&G Properties | Corpus Chrsti, TX 78413 | Oil & Gas Operator | Dec 2025 |
| 231 | Emerald Oil & Gas LC | Fort Worth, TX 76109 | Oil & Gas Operator | Dec 2025 |
| 232 | Encino Exploration, Inc. | George West, TX 78022 | Oil & Gas Operator | Dec 2025 |
| 233 | Energy 2000, Inc. | Reno, NV 89501 | Oil & Gas Operator | Dec 2025 |
| 234 | Energy Development Corporation | Houston, TX 77067 | Oil & Gas Operator | Dec 2024 |
| 235 | Energyquest II, LLC | The Woodlands, TX 77381 | Oil & Gas Operator | Oct 2025 |
| 236 | Enerquest Operating, LLC | Oklahoma City, OK 73114 | Oil & Gas Operator | Dec 2025 |
| 237 | Engroup Resources, L.P. | Houston, TX 77002 | Oil & Gas Operator | Dec 2025 |
| 238 | Enron Oil & Gas Company | Houston, TX 77210 | Oil & Gas Operator | Dec 1999 |
| 239 | Enserch Exploration Inc | Dallas, TX 75206 | Oil & Gas Operator | Apr 2015 |
| 240 | EOG Resources Inc | Midland, TX 79702 | Oil & Gas Operator | Dec 2025 |
| 241 | EP Energy E&P Company, LP | Houston, TX 77210 | Oil & Gas Operator | Jan 2023 |
| 242 | Erin Oil Co. | Midland, TX 79707 | Oil & Gas Operator | Dec 2025 |
| 243 | Esenjay Petroleum Corp. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Jul 1998 |
| 244 | Etc Field Services LLC | San Antonio, TX 78258 | Oil Operator | Jun 2018 |
| 245 | Etoco, L.P. | Houston, TX 77002 | Oil & Gas Operator | Dec 2025 |
| 246 | European-Southwest Co. | Houston, TX 77254 | Oil & Gas Operator | Dec 2025 |
| 247 | Everest Minerals Corp. | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Apr 2001 |
| 248 | Excalibur E & P, LLC | Johnson City, TX 78636 | Oil & Gas Operator | Dec 2025 |
| 249 | Exok Inc | Oklahoma City, OK 73116 | Oil & Gas Operator | Oct 2025 |
| 250 | Express Oil Co. | Hallettsville, TX 77964 | Oil & Gas Operator | Dec 2025 |
| 251 | Exxon Corporation | Houston, TX 77210 | Oil & Gas Operator | Jun 2024 |
| 252 | Exxon Mobil Corporation | Spring, TX 77389 | Oil & Gas Operator | Dec 2025 |
| 253 | Fair Operating, Inc. | Boerne, TX 78015 | Oil & Gas Operator | Dec 2025 |
| 254 | Faoc Operating LLC | Houston, TX 77057 | Oil Operator | Jun 2018 |
| 255 | Fargo Oil & Gas, LLC | Corpus Chrsti, TX 78415 | Oil & Gas Operator | Dec 2025 |
| 256 | Faulconer Energy, LLC | Tyler, TX 75711 | Oil & Gas Operator | Dec 2025 |
| 257 | Faulconer, Vernon E., Inc. | Tyler, TX 75711 | Oil & Gas Operator | Nov 2025 |
| 258 | Fesco, LTD. | Alice, TX 78332 | Oil Operator | Dec 2025 |
| 259 | Field Petroleum Corp. | San Antonio, TX 78216 | Oil & Gas Operator | Dec 2025 |
| 260 | Fina Oil And Chemical Company | Dallas, TX 75221 | Oil & Gas Operator | May 2019 |
| 261 | Finaly Resources LLC | Sunset Beach, CA 90742 | Oil & Gas Operator | Dec 2025 |
| 262 | Finley Resources Inc | Fort Worth, TX 76113 | Oil & Gas Operator | Dec 2025 |
| 263 | First Rock, Inc. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Dec 2025 |
| 264 | Firstrike Energy Corporation | Cleburne, TX 76033 | Oil & Gas Operator | Jan 2025 |
| 265 | Fischer Operating Corporation | Victoria, TX 77902 | Oil & Gas Operator | Jan 1999 |
| 266 | Flavian Oil Company | Dallas, TX 75206 | Gas Operator | Jan 1997 |
| 267 | Fletcher Operating, LLC | Fairhope, AL 36532 | Oil & Gas Operator | Dec 2025 |
| 268 | Fletcher Petroleum Corp. | Fairhope, AL 36533 | Oil & Gas Operator | Nov 2025 |
| 269 | Flournoy Production Co. | Alice, TX 78333 | Oil & Gas Operator | Dec 2002 |
| 270 | Forbes Producing, LLC | Corpus Chrsti, TX 78410 | Oil Operator | Sep 2025 |
| 271 | Forbes, C. C. Company | Alice, TX 78333 | Oil & Gas Operator | Sep 2015 |
| 272 | Forbes, Charles C. | Hebbronville, TX 78361 | Oil & Gas Operator | Jul 2011 |
| 273 | Forest Oil Corporation | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 274 | Forest Oil Permian Corporation | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 275 | Forney & McCombs | Houston, TX 77056 | Oil & Gas Operator | Jan 1998 |
| 276 | Forney Oil Corporation | Houston, TX 77056 | Oil & Gas Operator | Jan 1998 |
| 277 | Fort Apache Energy, Inc. | Boerne, TX 78015 | Oil & Gas Operator | Dec 2025 |
| 278 | Forza Operating, LLC | The Woodlands, TX 77380 | Oil & Gas Operator | Dec 2025 |
| 279 | Foster Energy Company | Tilden, TX 78072 | Oil & Gas Operator | Sep 2024 |
| 280 | Four Sevens Oil Co., LTD. | Fort Worth, TX 76102 | Oil & Gas Operator | Dec 2001 |
| 281 | Fox, Hewitt B., Inc. | Corpus Chrsti, TX 78411 | Oil & Gas Operator | Dec 2025 |
| 282 | Frank Louis L | Kingsville, TX 78364 | Oil & Gas Operator | Aug 2003 |
| 283 | Fredco | Louise, TX 77455 | Oil & Gas Operator | Dec 2025 |
| 284 | Frio Production Co. | Alice, TX 78333 | Oil & Gas Operator | Sep 1998 |
| 285 | Gaither Petroleum Corporation | Katy, TX 77493 | Oil & Gas Operator | Dec 2025 |
| 286 | Galindo Brothers, Inc. | Alice, TX 78333 | Oil & Gas Operator | Dec 2025 |
| 287 | Galloway Energy Co. | Tomball, TX 77377 | Oil & Gas Operator | Dec 2025 |
| 288 | Garcia, A. H. | San Diego, TX 78384 | Oil & Gas Operator | May 2006 |
| 289 | Garzaco Operating, LLC | Concepcion, TX 78349 | Oil & Gas Operator | Dec 2025 |
| 290 | Gasper Rice Resources, LTD. | Houston, TX 77068 | Oil & Gas Operator | Dec 2025 |
| 291 | Geiser Operating, Inc. | Portland, TX 78374 | Oil & Gas Operator | Sep 2019 |
| 292 | Genesis Producing Company | Houston, TX 77024 | Oil & Gas Operator | Oct 2007 |
| 293 | Geodyne Operating Company | Tulsa, OK 74103 | Oil & Gas Operator | Jun 2015 |
| 294 | Gillring Oil Company | Fort Worth, TX 76102 | Oil & Gas Operator | May 1994 |
| 295 | Global Natural Resources Corp. | Houston, TX 77002 | Oil & Gas Operator | May 1998 |
| 296 | Go-Energy Co. | San Antonio, TX 78232 | Oil & Gas Operator | Mar 2002 |
| 297 | Golden Gas Production Company | Tulsa, OK 74136 | Oil & Gas Operator | Sep 2025 |
| 298 | Goldking Prod. Co. | Houston, TX 77002 | Oil & Gas Operator | Apr 1998 |
| 299 | Gonzalez, Elia G. Mineral Trust | Laredo, TX 78041 | Oil & Gas Operator | May 2012 |
| 300 | Gould Oil Inc. | Wichita, KS 67278 | Oil & Gas Operator | Oct 2019 |