| 201 | Cross Timbers Operating Company | Fort Worth, TX 76102 | Oil & Gas Operator | Sep 2025 |
| 202 | Cross Timbers Production Co | Oklahoma City, OK 73102-5605 | Oil & Gas Operator | Mar 2005 |
| 203 | Crouch Petroleum Company | Amarillo, TX 79110 | Oil & Gas Operator | Mar 2015 |
| 204 | Crow Creek Operating Co III LLC | Tulsa, OK 74137-8432 | Oil & Gas Operator | Apr 2015 |
| 205 | Crown Central Pet Corp | Bellaire, TX 77401 | Oil & Gas Operator | Dec 2016 |
| 206 | Crusader Energy Corporation | Oklahoma City, OK 73102 | Oil & Gas Operator | Sep 2011 |
| 207 | Crusader Energy Group Inc. | Austin, TX 78746 | Oil & Gas Operator | Mar 2015 |
| 208 | Crusader Energy Group LLC | Oklahoma City, OK 73142 | Oil & Gas Operator | Mar 2015 |
| 209 | Csoda Operating Company LLC | Amarillo, TX 79114-7506 | Oil & Gas Operator | Aug 2021 |
| 210 | Cudd Operating Corp | Oklahoma City, OK 73118 | Oil & Gas Operator | Apr 2020 |
| 211 | Cummings Oil Company | Oklahoma City, OK 73112-6113 | Oil & Gas Operator | Dec 2025 |
| 212 | Curran Oil Co | Great Falls, MT 59401 | Gas Operator | May 2001 |
| 213 | D & B Oil Company | Graham, TX 76450 | Oil & Gas Operator | Feb 2026 |
| 214 | D & D Oil Company | Dayton, TX 77535 | Oil & Gas Operator | Feb 2026 |
| 215 | D C Energy, Inc. | Oklahoma City, OK 73134 | Oil & Gas Operator | Apr 2020 |
| 216 | Dab And Associates Inc | Crescent, OK 73028-0580 | Oil & Gas Operator | Nov 2014 |
| 217 | Dab Limited | Oklahoma City, OK 73116-9082 | Oil & Gas Operator | Aug 2013 |
| 218 | Dalcor Energy LLC | Duncan, OK 73534 | Oil & Gas Operator | Nov 2025 |
| 219 | Dalen Resources Oil & Gas Co | Dallas, TX 75206 | Oil & Gas Operator | Jun 2010 |
| 220 | Dallas Production, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Mar 2021 |
| 221 | Damson Oil Corporation | Houston, TX 77210 | Oil & Gas Operator | Mar 2005 |
| 222 | Daniels Earlene Inc | Follett, TX 79034-9736 | Oil & Gas Operator | Mar 2015 |
| 223 | Darnell Bobby J | Oklahoma City, OK 73112-8884 | Oil & Gas Operator | Dec 2025 |
| 224 | Darrah Oil Company, LLC | Wichita, KS 67201 | Oil & Gas Operator | Feb 2026 |
| 225 | Davis Operating Company | Elysian Field, TX 75642 | Oil & Gas Operator | Feb 2026 |
| 226 | Dawson Resources Inc | Franktown, CO 80116 | Oil & Gas Operator | Mar 2015 |
| 227 | Dawson-Markwell Exploration Co. | Oklahoma City, OK 73101 | Oil & Gas Operator | Nov 2025 |
| 228 | DCP Operating Co LP | Houston, TX 77042 | Oil & Gas Operator | Nov 2025 |
| 229 | Decalta International Corp | Denver, CO 80202 | Oil & Gas Operator | Mar 2015 |
| 230 | Dedica Energy Corporation | Mattoon, IL 61938 | Oil & Gas Operator | Mar 2008 |
| 231 | Dehart Company (The) | Ardmore, OK 73402 | Oil & Gas Operator | Dec 2025 |
| 232 | Deka Exploration Inc | Oklahoma City, OK 73113-0057 | Oil & Gas Operator | Nov 2019 |
| 233 | Denveramerican Petro LLC | | Oil & Gas Operator | May 2006 |
| 234 | Dette Oil Corporation | Oklahoma City, OK 73162-6249 | Oil & Gas Operator | Oct 2015 |
| 235 | Devon Energy Corp (Nevada) | Oklahoma City, OK 73102 | Oil & Gas Operator | Feb 2017 |
| 236 | Devon Energy Operating Corp | Oklahoma City, OK 73102 | Oil & Gas Operator | Apr 2013 |
| 237 | Devon Energy Production Company, L.P. | Oklahoma City, OK 73102 | Oil & Gas Operator | Feb 2026 |
| 238 | Devon Louisiana Corporation | Houston, TX 77002 | Oil & Gas Operator | Oct 2019 |
| 239 | Devon SFS Operating Inc | Oklahoma City, OK 73102 | Oil & Gas Operator | Mar 2008 |
| 240 | Dexxon Inc | Kiefer, OK 74041 | Oil & Gas Operator | Nov 2025 |
| 241 | Dillingham Ranch LC | Tulsa, OK 74152 | Oil & Gas Operator | May 2013 |
| 242 | Diversified Production LLC | Keithville, LA 71047 | Oil & Gas Operator | Feb 2026 |
| 243 | DLB Energy Corporation | Oklahoma City, OK 73118-1401 | Oil & Gas Operator | Dec 2014 |
| 244 | DLB Oil & Gas, Inc. | Big Lake, TX 76932 | Oil & Gas Operator | Feb 2026 |
| 245 | DMS Oil Company | Houston, TX 77042 | Oil & Gas Operator | Dec 2025 |
| 246 | Dominion Exploration & Production Inc | Houston, TX 77060 | Oil & Gas Operator | Apr 2015 |
| 247 | Dominion Ok TX E & P Inc | Oklahoma City, OK 73134 | Oil & Gas Operator | Nov 2018 |
| 248 | Dorchester Resources LP | Oklahoma City, OK 73154-8879 | Oil & Gas Operator | Aug 2021 |
| 249 | Double "C" Energy | Coweta, OK 74429 | Oil & Gas Operator | Mar 2015 |
| 250 | Drake Exploration Inc | Tulsa, OK 74105-4250 | Oil & Gas Operator | Dec 2025 |
| 251 | Drover Corporation (The) | Edmond, OK 73034 | Oil & Gas Operator | Aug 1992 |
| 252 | Duggan Stephen F | Boston, MA 2131 | Oil & Gas Operator | Jun 2010 |
| 253 | Duncan Jr J Walter | Oklahoma City, OK 73102 | Oil & Gas Operator | Dec 2016 |
| 254 | Dyco Petroleum Corporation | Tulsa, OK 74103 | Oil & Gas Operator | Mar 2015 |
| 255 | E R Operating Company | Dallas, TX 75225 | Oil & Gas Operator | Jan 2025 |
| 256 | E2 Operating LLC | Tulsa, OK 74135 | Oil & Gas Operator | Feb 2026 |
| 257 | Eagle Rock Mid-Continent Operating LLC | Tulsa, OK 74103-3703 | Oil & Gas Operator | Nov 2025 |
| 258 | Edinger Engineering, Inc. | Oklahoma City, OK 73102 | Oil & Gas Operator | Dec 2025 |
| 259 | Edinger Inc. | Oklahoma City, OK 73102 | Oil & Gas Operator | Jun 2007 |
| 260 | Ehrlich, Mitchell | Perryton, TX 79070 | Oil & Gas Operator | May 1999 |
| 261 | Eight Round Corporation | Seminole, OK 74818-1482 | Oil & Gas Operator | Jul 2012 |
| 262 | Ekg Operating Inc | Seminole, OK 74818-1028 | Oil & Gas Operator | Nov 2015 |
| 263 | El Paso Production Company | Houston, TX 77002 | Oil & Gas Operator | Mar 2016 |
| 264 | Eland Energy Inc | Dallas, TX 75248 | Oil & Gas Operator | Dec 2025 |
| 265 | Elder & Vaughn Inc | Oklahoma City, OK 73154-0938 | Oil & Gas Operator | Mar 2008 |
| 266 | Elite Tank Trucks, Inc | | Oil & Gas Operator | Nov 2025 |
| 267 | Elvera Stiles Trust | Broken Arrow, OK 74011 | Oil & Gas Operator | Apr 2025 |
| 268 | Encana Energy Resources Inc | Denver, CO 80202-2828 | Oil & Gas Operator | Feb 2024 |
| 269 | Encino Operating, LLC | Houston, TX 77057 | Oil & Gas Operator | Feb 2026 |
| 270 | Encore Operating LP | Plano, TX 75024 | Oil & Gas Operator | Dec 2025 |
| 271 | Energon Oil, Inc. | Amarillo, TX 79114 | Oil & Gas Operator | Feb 2026 |
| 272 | Energy Production Services LLC | Oklahoma City, OK 73162-4736 | Oil & Gas Operator | Apr 2020 |
| 273 | Energyquest II, LLC | The Woodlands, TX 77381 | Oil & Gas Operator | Nov 2025 |
| 274 | Enervest Operating LLC | Houston, TX 77002 | Oil & Gas Operator | Feb 2026 |
| 275 | Enex Resources Corporation | Houston, TX 77002 | Oil & Gas Operator | Dec 2009 |
| 276 | Enexco, Inc. | Dallas, TX 75243 | Oil & Gas Operator | Mar 2017 |
| 277 | Enserch Exploration Inc | Dallas, TX 75206 | Oil & Gas Operator | Apr 2015 |
| 278 | Ensource Inc | Midland, TX 79705 | Oil & Gas Operator | Aug 1998 |
| 279 | EOG (Oklahoma) Inc. | Oklahoma City, OK 73112 | Oil & Gas Operator | Oct 2016 |
| 280 | EOG Resources, Inc. | Midland, TX 79702 | Oil & Gas Operator | Feb 2026 |
| 281 | Eott Energy Corporation | Oklahoma City, OK 73118 | Oil & Gas Operator | Dec 1995 |
| 282 | Eott Energy Operating LP | Houston, TX 77210-4666 | Oil & Gas Operator | Oct 2009 |
| 283 | EP Energy E&P Company, LP | Houston, TX 77210 | Oil & Gas Operator | Jan 2023 |
| 284 | Esenjay Exploration, Inc | Houston, TX 77042 | Oil & Gas Operator | Nov 2025 |
| 285 | Esis Inc | | Oil & Gas Operator | Feb 2017 |
| 286 | Esperanza Energy Corp. | Prosper, TX 75078 | Oil & Gas Operator | Mar 2015 |
| 287 | Evolution Energy LLC | Oklahoma City, OK 73116 | Oil & Gas Operator | Nov 2025 |
| 288 | Ew Carter Oil Co;Inc | | Oil & Gas Operator | Nov 2025 |
| 289 | Exco Resources Inc | Dallas, TX 75251 | Oil & Gas Operator | Nov 2025 |
| 290 | Executive Properties Inc | Amarillo, TX 79110 | Oil & Gas Operator | Aug 1994 |
| 291 | Export Petroleum Corporation | Fort Worth, TX 76147 | Oil & Gas Operator | Feb 2026 |
| 292 | Exxon Mobil Corporation | Spring, TX 77389 | Oil & Gas Operator | Feb 2026 |
| 293 | Exxonmobil Oil Corp | Houston, TX 77210 | Oil & Gas Operator | Sep 2025 |
| 294 | F C D Oil Corporation | Oklahoma City, OK 73112 | Oil & Gas Operator | Feb 1995 |
| 295 | Fail W T Inc | | Oil & Gas Operator | Mar 2015 |
| 296 | Fairway Resources Operating III LLC | Houston, TX 77002-2728 | Oil & Gas Operator | Nov 2025 |
| 297 | Falcon Oil & Gas Company, Inc. | Houston, TX 77002 | Oil & Gas Operator | Nov 2022 |
| 298 | Farris Well Service LLC | Liberal, KS 67901-5644 | Oil & Gas Operator | Jul 2016 |
| 299 | Faulconer Energy, LLC | Tyler, TX 75711 | Oil & Gas Operator | Feb 2026 |
| 300 | Faulconer, Vernon E., Inc. | Tyler, TX 75711 | Oil & Gas Operator | Dec 2025 |