| 201 | Cox Gas Corporation | Dallas, TX 75201-7306 | Oil & Gas Operator | Apr 2015 |
| 202 | Cox Oil & Gas Inc | Dallas, TX 75201 | Oil & Gas Operator | Mar 2014 |
| 203 | Cox, John L. | Midland, TX 79702 | Oil & Gas Operator | Mar 2015 |
| 204 | CPRC Inc | Tulsa, OK 74103-5037 | Oil & Gas Operator | Apr 1997 |
| 205 | Crawley Petroleum Corporation | Oklahoma City, OK 73102 | Oil & Gas Operator | Apr 2026 |
| 206 | CRB Resources Inc | Oklahoma City, OK 73118 | Oil & Gas Operator | Jan 2026 |
| 207 | Cross Timbers Oil Company | Dallas, TX 75284 | Oil & Gas Operator | May 2013 |
| 208 | Cross Timbers Operating Company | Fort Worth, TX 76102 | Oil & Gas Operator | Dec 2025 |
| 209 | Cross Timbers Production Co | Oklahoma City, OK 73102-5605 | Oil & Gas Operator | Mar 2005 |
| 210 | Crown Central Pet Corp | Bellaire, TX 77401 | Oil & Gas Operator | Dec 2016 |
| 211 | Crown Energy Company | Oklahoma City, OK 73106 | Oil & Gas Operator | Feb 2026 |
| 212 | Crusader Energy Corporation | Oklahoma City, OK 73102 | Oil & Gas Operator | Sep 2011 |
| 213 | Crusader Energy Group Inc. | Austin, TX 78746 | Oil & Gas Operator | Mar 2015 |
| 214 | Crusader Energy Group LLC | Oklahoma City, OK 73142 | Oil & Gas Operator | Mar 2015 |
| 215 | Crusader Energy II LLC | Oklahoma City, OK 73102 | Oil & Gas Operator | Mar 2015 |
| 216 | Crusader Energy III LLC | Oklahoma City, OK 73142-1856 | Oil & Gas Operator | Feb 2011 |
| 217 | Cudd Operating Corp | Oklahoma City, OK 73118 | Oil & Gas Operator | Apr 2020 |
| 218 | Culebra Oil & Gas, LLC | Kerrville, TX 78028 | Oil & Gas Operator | Apr 2026 |
| 219 | Cummings Oil Company | Oklahoma City, OK 73112-6113 | Oil & Gas Operator | Feb 2026 |
| 220 | Curzon Operating Company LTD | Oklahoma City, OK 73118-4821 | Oil & Gas Operator | Jan 2026 |
| 221 | D & B Operating LLC | Ringwood, OK 73768 | Oil Operator | Jan 2023 |
| 222 | D & D Pipe & Equipment Inc | Kingfisher, OK 73750 | Oil & Gas Operator | Mar 2005 |
| 223 | D & J Oil Company | Kermit, TX 79745 | Oil & Gas Operator | Apr 2026 |
| 224 | D & J Oil Company Of Okla Inc | Enid, OK 73706-0129 | Oil & Gas Operator | May 1999 |
| 225 | D & T Swabbing & Well Serv Inc | Hennessey, OK 73742-0124 | Oil & Gas Operator | Dec 2025 |
| 226 | D C Energy, Inc. | Oklahoma City, OK 73134 | Oil & Gas Operator | Apr 2020 |
| 227 | Dalcor Energy LLC | Duncan, OK 73534 | Oil & Gas Operator | Nov 2025 |
| 228 | Damson Oil Corporation | Houston, TX 77210 | Oil & Gas Operator | Mar 2005 |
| 229 | Dance Oil Co | Denver, CO 80202 | Oil & Gas Operator | May 1993 |
| 230 | Darrah Oil Company, LLC | Wichita, KS 67201 | Oil & Gas Operator | Apr 2026 |
| 231 | Dash Operating LLC | Oklahoma City, OK 73118-5031 | Oil & Gas Operator | Dec 2025 |
| 232 | David E Morgan Inc | Danville, CA 94506-2035 | Oil & Gas Operator | Feb 2026 |
| 233 | Dawson Resources Inc | Franktown, CO 80116 | Oil & Gas Operator | Mar 2015 |
| 234 | Dawson-Markwell Exploration Co. | Oklahoma City, OK 73101 | Oil & Gas Operator | Jan 2026 |
| 235 | DCP Operating Co LP | Houston, TX 77042 | Oil & Gas Operator | Nov 2025 |
| 236 | Delta D Operations | Wilson, OK 73463 | Oil & Gas Operator | Jul 2014 |
| 237 | Deminex U S Oil Company | | Oil & Gas Operator | Jan 1998 |
| 238 | Dette Oil Corporation | Oklahoma City, OK 73162-6249 | Oil & Gas Operator | Oct 2015 |
| 239 | Devon Energy Corp (Nevada) | Oklahoma City, OK 73102 | Oil & Gas Operator | Feb 2017 |
| 240 | Devon Energy Production Company, L.P. | Oklahoma City, OK 73102 | Oil & Gas Operator | Apr 2026 |
| 241 | Devon Louisiana Corporation | Houston, TX 77002 | Oil & Gas Operator | Oct 2019 |
| 242 | Dinsmore C E | Enid, OK 73702 | Oil & Gas Operator | May 2009 |
| 243 | Diversified Production LLC | Keithville, LA 71047 | Oil & Gas Operator | Apr 2026 |
| 244 | Dixie Petroleum Inc | Cashion, OK 73016 | Oil & Gas Operator | May 2001 |
| 245 | DLB Energy Corporation | Oklahoma City, OK 73118-1401 | Oil & Gas Operator | Dec 2014 |
| 246 | DLB Oil & Gas, Inc. | Big Lake, TX 76932 | Oil & Gas Operator | Apr 2026 |
| 247 | DMS Oil Company | Houston, TX 77042 | Oil & Gas Operator | Jan 2026 |
| 248 | Dominion Exploration & Production Inc | Houston, TX 77060 | Oil & Gas Operator | Apr 2015 |
| 249 | Dominion Ok TX E & P Inc | Oklahoma City, OK 73134 | Oil & Gas Operator | Nov 2018 |
| 250 | Dorchester Resources LP | Oklahoma City, OK 73154-8879 | Oil & Gas Operator | Aug 2021 |
| 251 | Dorey Oil Corporation | Healdton, OK 73438-0856 | Oil Operator | Apr 2014 |
| 252 | Douglass Dietz & Daley Inc | Oklahoma City, OK 73154-0125 | Oil & Gas Operator | Aug 2023 |
| 253 | Draco Production Company | Tulsa, OK 74133 | Oil & Gas Operator | Jul 2012 |
| 254 | Drake Exploration Inc | Tulsa, OK 74105-4250 | Oil & Gas Operator | Feb 2026 |
| 255 | Driver Energy Of Texas | Dallas, TX 75379-5951 | Oil & Gas Operator | Apr 2011 |
| 256 | Duncan Jr J Walter | Oklahoma City, OK 73102 | Oil & Gas Operator | Dec 2016 |
| 257 | Duncan Oil Properties, Inc. | Oklahoma City, OK 73102 | Oil & Gas Operator | Apr 2026 |
| 258 | Dyco Petroleum Corporation | Tulsa, OK 74103 | Oil & Gas Operator | Mar 2015 |
| 259 | E Lyle Johnson Inc | Oklahoma City, OK 73142 | Oil & Gas Operator | Jan 2026 |
| 260 | Ea Petroleum Inc | Norman, OK 73072-4147 | Oil & Gas Operator | May 2006 |
| 261 | Eagle Creek Resources, LLC | Sewickley, PA 15143 | Oil & Gas Operator | Dec 2024 |
| 262 | Eagle Petroleum Corporation | Holliday, TX 76366 | Oil & Gas Operator | Oct 2005 |
| 263 | Eagle Rock Mid-Continent Operating LLC | Tulsa, OK 74103-3703 | Oil & Gas Operator | Jan 2026 |
| 264 | Earlsboro Energies Corporation | Oklahoma City, OK 73116-3605 | Oil & Gas Operator | Jan 2026 |
| 265 | Edinger Engineering, Inc. | Oklahoma City, OK 73102 | Oil & Gas Operator | Feb 2026 |
| 266 | Edinger Inc. | Oklahoma City, OK 73102 | Oil & Gas Operator | Jun 2007 |
| 267 | Edisto Resources Corporation | Houston, TX 77057 | Oil & Gas Operator | Oct 1999 |
| 268 | Eec Inc | Norman, OK 73072 | Oil & Gas Operator | Feb 2026 |
| 269 | El Coqui' Oil Company | Tussy, OK 73088 | Oil & Gas Operator | Oct 2009 |
| 270 | El Paso Production Company | Houston, TX 77002 | Oil & Gas Operator | Mar 2016 |
| 271 | Elder & Vaughn Inc | Oklahoma City, OK 73154-0938 | Oil & Gas Operator | Mar 2008 |
| 272 | Elite Tank Trucks, Inc | | Oil & Gas Operator | Dec 2025 |
| 273 | Emc Exploration Company Inc | Oklahoma City, OK 73103-3775 | Oil & Gas Operator | Jul 2007 |
| 274 | Encore Operating LP | Plano, TX 75024 | Oil & Gas Operator | Feb 2026 |
| 275 | Energy Production Services LLC | Oklahoma City, OK 73162-4736 | Oil & Gas Operator | Apr 2020 |
| 276 | Enervest Operating LLC | Houston, TX 77002 | Oil & Gas Operator | Apr 2026 |
| 277 | Enex Resources Corporation | Houston, TX 77002 | Oil & Gas Operator | Dec 2009 |
| 278 | Enexco, Inc. | Dallas, TX 75243 | Oil & Gas Operator | Mar 2017 |
| 279 | Enserch Exploration Inc | Dallas, TX 75206 | Oil & Gas Operator | Apr 2015 |
| 280 | Entex Petroleum Inc | Oklahoma City, OK 73113 | Oil & Gas Operator | Nov 1997 |
| 281 | EOG (Oklahoma) Inc. | Oklahoma City, OK 73112 | Oil & Gas Operator | Oct 2016 |
| 282 | EOG Resources Inc | Midland, TX 79702 | Oil & Gas Operator | Apr 2026 |
| 283 | Eott Energy Corporation | Oklahoma City, OK 73118 | Oil & Gas Operator | Dec 1995 |
| 284 | EP Energy E&P Company, LP | Houston, TX 77210 | Oil & Gas Operator | Jan 2023 |
| 285 | EP Operating LP | Dallas, TX 75201 | Oil & Gas Operator | Mar 2015 |
| 286 | Esco Exploration, Inc | Dallas, TX 75201 | Oil & Gas Operator | Mar 2015 |
| 287 | Esenjay Exploration, Inc | Houston, TX 77042 | Oil & Gas Operator | Jan 2026 |
| 288 | Esis Inc | | Oil & Gas Operator | Feb 2017 |
| 289 | Essman Energy, LLC | Tulsa, OK 74136 | Oil & Gas Operator | Sep 2019 |
| 290 | Evolution Energy LLC | Oklahoma City, OK 73116 | Oil & Gas Operator | Feb 2026 |
| 291 | Excalibur Resources LLC | Houston, TX 77002-5220 | Oil & Gas Operator | Feb 2026 |
| 292 | Excelco Energy Inc. | Kingwood, TX 77339 | Oil & Gas Operator | Jul 2018 |
| 293 | Exco Resources Inc | Dallas, TX 75251 | Oil & Gas Operator | Jan 2026 |
| 294 | Exok Inc | Oklahoma City, OK 73116 | Oil & Gas Operator | Jan 2026 |
| 295 | Exploration Associates II LLC | Oklahoma City, OK 73102-8815 | Oil & Gas Operator | Jan 2013 |
| 296 | Exxon Mobil Corporation | Spring, TX 77389 | Oil & Gas Operator | Apr 2026 |
| 297 | F C D Oil Corporation | Oklahoma City, OK 73112 | Oil & Gas Operator | Feb 1995 |
| 298 | Fairway Resources Operating III LLC | Houston, TX 77002-2728 | Oil & Gas Operator | Jan 2026 |
| 299 | Farmers Energy Corporation | Tulsa, OK 74103-3525 | Oil & Gas Operator | Nov 2021 |
| 300 | Faulconer Energy, LLC | Tyler, TX 75711 | Oil & Gas Operator | Apr 2026 |