| 301 | Abercrombie Drilling, Inc. | Wichita, KS 67202 | Oil Operator | May 1997 |
| 302 | Abercrombie Energy, LLC | Wichita, KS 67212 | Oil & Gas Operator | Mar 2025 |
| 303 | Abercrombie, A. L., Inc | Wichita, KS 67202 | Oil & Gas Operator | Jan 2025 |
| 304 | Aberdeen American Petroleum Co., Inc. | | Oil & Gas Operator | Dec 1989 |
| 305 | Aberdeen Petroleum (USA) Inc. | Abilene, TX 79608 | Oil & Gas Operator | Sep 1994 |
| 306 | Aberlour Operating Inc. | Pampa, TX 79066 | Oil & Gas Operator | Jul 2025 |
| 307 | Abernathy Auto, Inc. | Abilene, TX 79604 | Oil & Gas Operator | Jul 2025 |
| 308 | Abernathy Exploration Company | Abilene, TX 79608 | Oil & Gas Operator | Mar 2002 |
| 309 | Abilene American Energy, LLC | Abilene, TX 79602 | Oil Operator | Jul 2025 |
| 310 | Ablaze Drilling Company | Garland, TX 75044-2912 | Oil & Gas Operator | Aug 2013 |
| 311 | Ableready, Inc. | Houston, TX 77269 | Oil & Gas Operator | Jul 2025 |
| 312 | Abney Oil Company, Inc. | | Oil Operator | Mar 1981 |
| 313 | Abng Inc | Chickasha, OK 73023-0926 | Oil & Gas Operator | Feb 2017 |
| 314 | Abo Petroleum Corp | Artesia, NM 88210 | Oil & Gas Operator | Jul 1988 |
| 315 | Abps Energy Inc | Chickasha, OK 73023-1658 | Oil & Gas Operator | Apr 2015 |
| 316 | Abraxas Petroleu | | Oil Operator | May 1986 |
| 317 | Abraxas Petroleum Corporation | San Antonio, TX 78259 | Oil & Gas Operator | Jul 2025 |
| 318 | Abraxas Production Corporation | San Antonio, TX 78270 | Oil & Gas Operator | Sep 1999 |
| 319 | Abs Oil, Inc. | Piqua, KS 66761 | Oil Operator | Apr 2022 |
| 320 | Absolute Energy Corp | Columbus, OH 43213 | Oil & Gas Operator | Dec 1997 |
| 321 | Abtex Energy, Inc. | Abilene, TX 79608 | Oil & Gas Operator | May 2006 |
| 322 | Abundance Energy I LLC | Tulsa, OK 74114 | Gas Operator | Apr 2025 |
| 323 | Abundance Energy LLC | Bartlesville, OK 74005-1087 | Oil & Gas Operator | Jul 2018 |
| 324 | Abundance Energy Services LLC | Tulsa, OK 74114 | Gas Operator | May 2025 |
| 325 | Abx Oil & Gas, Inc. | Dallas, TX 75240 | Oil & Gas Operator | Jul 2025 |
| 326 | Ac Exploration, LLC | Houston, TX 77024 | Oil & Gas Operator | Jul 2025 |
| 327 | Ac Oil & Gas LLC | Hennessey, OK 73742 | Oil & Gas Operator | May 2025 |
| 328 | Ac Oil LLC | Limestone, NY 14753 | Oil & Gas Operator | Dec 2024 |
| 329 | Ac Operating Company LLC | Houston, TX 77024-2851 | Oil Operator | May 2025 |
| 330 | Acacia Exploration Partners LLC | Oklahoma City, OK 73102-5804 | Oil & Gas Operator | Nov 2021 |
| 331 | Acacia Operating Company, LLC | Midland, TX 79701 | Oil Operator | Jul 2024 |
| 332 | Acacia Operating, LLC | | Oil & Gas Operator | Apr 2025 |
| 333 | Acadia Oil Company | Wichita Falls, TX 76309 | Oil & Gas Operator | Sep 2007 |
| 334 | Acadia Oil, LLC | Wichita Falls, TX 76310 | Oil Operator | Jul 2025 |
| 335 | Acadian Gas Pipeline System | | Oil Operator | Jan 2025 |
| 336 | Acadian Land & Expl., Inc. | | Oil & Gas Operator | May 1992 |
| 337 | Acadiana Gas Systems, Inc. | | Oil & Gas Operator | Jan 1999 |
| 338 | Acadiana Reserves, Inc. | | Oil & Gas Operator | Oct 1984 |
| 339 | Acadienergy, Inc. | | Oil & Gas Operator | Jun 1988 |
| 340 | Accell Natural Gas Company | Houston, TX 77042 | Oil & Gas Operator | Sep 1998 |
| 341 | Access Petroleum Corporation | | Oil & Gas Operator | Mar 2015 |
| 342 | Access Resources Inc. | Healdton, OK 73438 | Oil & Gas Operator | Sep 2005 |
| 343 | Accidental Oil Company Inc | Newcastle, WY 82701 | Oil & Gas Operator | Feb 2021 |
| 344 | Accidie Exploration And Dev.,Inc | Plano, TX 75023 | Oil & Gas Operator | Jul 2025 |
| 345 | Acco Oil & Gas Company | Houston, TX 77056 | Oil & Gas Operator | Sep 2001 |
| 346 | Ace Drilling Services, Inc. | | Oil & Gas Operator | Sep 1987 |
| 347 | Ace Energy LLC | Leawood, KS 66211 | Oil & Gas Operator | Apr 2025 |
| 348 | Ace Oil Company | | Oil Operator | Mar 2025 |
| 349 | Ace Production | | Oil Operator | Jul 1993 |
| 350 | Ace Productions | Beaumont, TX 77707 | Oil & Gas Operator | Jul 2025 |
| 351 | Aceco Petroleum Co | Artesia, NM 88210 | Oil & Gas Operator | Sep 2002 |
| 352 | Aceite Energy Corp | | Oil & Gas Operator | Feb 2007 |
| 353 | Aceite Inc | Farmington, NM 87499 | Oil & Gas Operator | Apr 1998 |
| 354 | Acelco Inc | Norman, OK 73070 | Oil & Gas Operator | Oct 1996 |
| 355 | Achen Oil & Gas Inc. | Artesia, NM 88211 | Oil & Gas Operator | Feb 1999 |
| 356 | Achilles Oil, LLC | | Oil & Gas Operator | Apr 2025 |
| 357 | Acierto Resources Company, LLC | Houston, TX 77070 | Oil & Gas Operator | Jul 2025 |
| 358 | Acirema Corporation | Longview, TX 75608 | Oil & Gas Operator | Jul 2025 |
| 359 | Acker, H. E. Well Service | | Oil & Gas Operator | Dec 2007 |
| 360 | Ackerly Service Company, Inc. | Big Spring, TX 79721 | Oil & Gas Operator | Nov 1997 |
| 361 | Ackerman, Albert C. | Boerne, TX 78006 | Oil & Gas Operator | Oct 1995 |
| 362 | Ackley Earl H & Glenora Trust | Cushing, OK 74023-5230 | Oil & Gas Operator | Mar 2015 |
| 363 | Acl Production, LLC | Independence, KS 67301 | Oil Operator | Sep 2017 |
| 364 | Acme Petroleum Co. | Gonzales, TX 78629 | Oil & Gas Operator | Mar 2008 |
| 365 | Acock Engineering & Assoc., Inc. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Jul 2002 |
| 366 | Acock Operating Limited | San Antonio, TX 78270 | Oil & Gas Operator | Jul 2025 |
| 367 | Acock/Anaqua Operating Co., LC | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Apr 2004 |
| 368 | Acock/Anaqua Operating Co., LP | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Jul 2025 |
| 369 | Acoma Oil Corporation | Saint Paul, MN 55102 | Oil & Gas Operator | Jul 2025 |
| 370 | Acoma Operating, LLC | Lubbock, TX 79424 | Oil & Gas Operator | Jul 2025 |
| 371 | Acorn Oil & Gas, Inc. | Orchard, TX 77464 | Oil Operator | Sep 2017 |
| 372 | Acorn Oil & Gas, LLC | Iraan, TX 79744 | Oil & Gas Operator | Jul 2025 |
| 373 | Acott, Melvin E | | Oil Operator | Aug 2014 |
| 374 | Actagon Corp | Monroeville, PA 15146 | Oil & Gas Operator | Dec 2024 |
| 375 | Action Oil Co Inc | Farmington, NM 87499 | Oil Operator | Mar 2021 |
| 376 | Action Petroleum Inc | Atwater, OH 44201 | Oil & Gas Operator | Dec 1986 |
| 377 | Action Petroleum Service Corp | Ardmore, OK 73401 | Oil Operator | Apr 2025 |
| 378 | Activa Resources, LLC | San Antonio, TX 78205 | Oil & Gas Operator | Jul 2025 |
| 379 | Activa Resources, LTD. | San Antonio, TX 78205 | Oil & Gas Operator | Mar 2008 |
| 380 | Ad Astra Resources LLC | Wichita, KS 67212 | Oil & Gas Operator | May 2025 |
| 381 | Ada Belle Oil & Gas Company | Sourlake, TX 77659 | Oil Operator | Dec 2023 |
| 382 | Ada Energy Exploration And Production LLC | Ada, OK 74820-0867 | Oil Operator | Apr 2025 |
| 383 | Ada Exploration | Olney, TX 76374 | Oil & Gas Operator | Jul 2025 |
| 384 | Ada Oil Exploration Corp | | Oil & Gas Operator | Jan 1986 |
| 385 | Adair E H Oil Co | | Oil & Gas Operator | Aug 1994 |
| 386 | Adair Resources Inc. | Ennis, TX 75120 | Oil & Gas Operator | Apr 2018 |
| 387 | Adair W C & Co Inc. | Logan, OH 43138 | Oil & Gas Operator | Dec 1991 |
| 388 | Adam Petroleum Services, Inc. | | Oil Operator | Aug 1989 |
| 389 | Adam'S Gas Corporation, Inc. | Albert, KS 67511 | Gas Operator | Mar 2004 |
| 390 | Adami Compressor Service | Weatherford, TX 76086 | Gas Operator | Jul 2025 |
| 391 | Adams & McGahey | Amarillo, TX 79114 | Oil & Gas Operator | Nov 1998 |
| 392 | Adams Affiliates, Inc. | Tulsa, OK 74121 | Oil & Gas Operator | Jul 2025 |
| 393 | Adams Branch Exploration Company | Abilene, TX 79608 | Oil & Gas Operator | Jul 2002 |
| 394 | Adams Energy LLC | | Oil & Gas Operator | Dec 2021 |
| 395 | Adams Evertte | Tulsa, OK 74103 | Oil & Gas Operator | Mar 2015 |
| 396 | Adams G C Oil & | | Oil & Gas Operator | Nov 1996 |
| 397 | Adams H D LLC | Moorcroft, WY 82721 | Oil & Gas Operator | May 2025 |
| 398 | Adams Res & Energy Co | Houston, TX 77001-0844 | Oil & Gas Operator | Mar 2015 |
| 399 | Adams Resources Expl. Corp. | Houston, TX 77001 | Oil & Gas Operator | Apr 2020 |
| 400 | Adams, Frank B | Corpus Christi, TX 78476 | Oil & Gas Operator | Feb 1988 |