| 301 | Adamson Exploration Co. | Kilgore, TX 75662 | Oil Operator | Feb 2019 |
| 302 | Adamson Exploration Corporation | Kilgore, TX 75663 | Oil & Gas Operator | Mar 2008 |
| 303 | Adamson, Michael A. | Sapulpa, OK 74066 | Oil Operator | Oct 2015 |
| 304 | Adco LTD. | | Oil & Gas Operator | Dec 1983 |
| 305 | Adco Producing Co. | Natchez, MS 39120 | Oil & Gas Operator | Mar 1989 |
| 306 | Adcock, Carol | Ozona, TX 76943 | Oil & Gas Operator | Feb 2019 |
| 307 | Adcock, Leroy | | Oil & Gas Operator | Jun 2009 |
| 308 | Add Energy Co | Butler, PA 16002-0471 | Gas Operator | Dec 2018 |
| 309 | Addax Operating, LLC | Wichita Falls, TX 76307 | Oil & Gas Operator | Feb 2019 |
| 310 | Addie, James & John Thornton | | Oil & Gas Operator | Oct 2018 |
| 311 | Addington Exploration, LLC | | Oil & Gas Operator | Dec 2016 |
| 312 | Addis Family Tru | | Oil Operator | Apr 1992 |
| 313 | Addis, Icer Estate Of | Wichita, KS 67208 | Gas Operator | Jun 2015 |
| 314 | Addison - Graves, L.L.C. | Archer City, TX 76351 | Oil Operator | Feb 2019 |
| 315 | Addison Oil, LLC | Addison, TX 75001 | Oil & Gas Operator | Mar 2013 |
| 316 | Addison Resources Inc. | | Oil & Gas Operator | Jul 1998 |
| 317 | Addison, Kenneth | | Oil & Gas Operator | Dec 2017 |
| 318 | Adeco, Inc. | Hays, KS 67601 | Oil Operator | Nov 2018 |
| 319 | Adela Oil | | Oil & Gas Operator | Jun 2000 |
| 320 | Adena Petroleum Inc | Vienna, WV 26105 | Oil & Gas Operator | Dec 2017 |
| 321 | Adenryen, LTD. Co. | Sulphur SPGS, TX 75483 | Oil Operator | Feb 2019 |
| 322 | Adexco Operating Company | Fort Worth, TX 76102 | Oil & Gas Operator | Feb 2019 |
| 323 | Adgo Resources LLC | Midland, TX 79701 | Oil Operator | Nov 2018 |
| 324 | Adkins Production Co. | | Oil Operator | Aug 2015 |
| 325 | Adkins, Franklin | Ona, WV 25545-0070 | Oil & Gas Operator | Dec 2017 |
| 326 | Adkins, Michael H. | Austin, TX 78767 | Gas Operator | Feb 2019 |
| 327 | Adkins, R. L. Corp. | Lubbock, TX 79408 | Oil & Gas Operator | Jun 2013 |
| 328 | Adkins, Russell M & Mary | Louisa, KY 41230 | Oil Operator | Dec 2014 |
| 329 | Adkins, Teddy | Spencer, WV 25276 | Oil & Gas Operator | Dec 2017 |
| 330 | Adm Industrial O | | Oil Operator | Nov 1989 |
| 331 | Admiral Bay (USA) Inc. | Centennial, CO 80112 | Gas Operator | Jun 2011 |
| 332 | Adobe Energy Company | | Oil & Gas Operator | Sep 2010 |
| 333 | Adobe Energy, Inc. | | Oil & Gas Operator | Nov 2004 |
| 334 | Adobe Operating Company | Pampa, TX 79066-1817 | Oil & Gas Operator | Feb 2019 |
| 335 | Adobe Resources Corporation | Midland, TX 79701 | Oil & Gas Operator | Dec 2000 |
| 336 | Adparo LLC | | Gas Operator | Jan 2019 |
| 337 | Adr Operating, Inc. | Independence, KS 67301 | Oil & Gas Operator | Sep 2013 |
| 338 | Ads | | Oil & Gas Operator | Dec 2010 |
| 339 | Ads Oil & Gas, Inc. | Caldwell, TX 77836 | Oil & Gas Operator | Feb 2019 |
| 340 | Advance Energy Partners Hat Mesa, LLC | Houston, TX 77077 | Oil & Gas Operator | Aug 2018 |
| 341 | Advance Exploration | Abilene, TX 79601 | Oil & Gas Operator | Feb 2019 |
| 342 | Advance Oil Corporation | Kiefer, OK 74041-4105 | Oil & Gas Operator | May 2017 |
| 343 | Advanced Petro Corp | Hamburg, NY 14075-5003 | Oil & Gas Operator | Dec 1992 |
| 344 | Advanced Petroleum Enhancement, Inc | Madisonville, KY 42431 | Oil & Gas Operator | Dec 2015 |
| 345 | Advanced Wireless Communications, L.L.C. | Farmington, NM 87402 | Oil & Gas Operator | Sep 2018 |
| 346 | Advantage Oil & Gas, Inc. | Pinehurst, TX 77362-3917 | Oil & Gas Operator | Feb 2019 |
| 347 | Advantage Resour | | Oil & Gas Operator | May 1994 |
| 348 | Advantage Resources Inc | Denver, CO 80203 | Oil & Gas Operator | Nov 2018 |
| 349 | Advantagewon Oil, Us, Corp. | Batson, TX 77519 | Oil Operator | Feb 2019 |
| 350 | Adventure Expl Partners II, LLC | Midland, TX 79701 | Oil & Gas Operator | Oct 2014 |
| 351 | Adventure Exploration Partners, LLC | Midland, TX 79702 | Oil & Gas Operator | Oct 2011 |
| 352 | Adventure Exploration PTRS, LLC | | Oil & Gas Operator | Aug 2012 |
| 353 | Adventure Operating Company, LLC | Midland, TX 79702 | Oil & Gas Operator | Feb 2019 |
| 354 | Adventure Properties Inc | Seminole, OK 74868-1296 | Oil Operator | Sep 2017 |
| 355 | Aec Operating Company | Roswell, NM 88202-1973 | Oil & Gas Operator | Sep 2006 |
| 356 | Aed Development Inc | Columbus, OH 43220 | Oil & Gas Operator | Dec 1995 |
| 357 | Aegean Oil & Gas Inc | Brunswick, OH 44212 | Oil & Gas Operator | Dec 1993 |
| 358 | Aegean Petroleum | | Oil Operator | Mar 1982 |
| 359 | Aegis Energy, Inc. | | Oil & Gas Operator | Sep 1998 |
| 360 | Aegis Fluids Management, LLC | Plano, TX 75093 | Oil & Gas Operator | Feb 2019 |
| 361 | Aegis Operating Co., Inc. | Puckett, MS 39151 | Oil & Gas Operator | Dec 2018 |
| 362 | Aeon Energy Corp. | | Oil & Gas Operator | Jan 2019 |
| 363 | Aeon Operating, Inc. | Plano, TX 75093 | Oil & Gas Operator | Feb 2019 |
| 364 | Aera Energy LLC | Bakersfield, CA 93311-1301 | Oil & Gas Operator | Jan 2018 |
| 365 | Aerie Energy | Floresville, TX 78114 | Oil Operator | Feb 2019 |
| 366 | Aesir Energy | | Oil Operator | Sep 2011 |
| 367 | Aethon Energy Operating LLC | Dallas, TX 75251 | Oil & Gas Operator | Dec 2019 |
| 368 | Aethon I LP | Dallas, TX 75206-5170 | Oil & Gas Operator | Nov 2007 |
| 369 | Aexco Petroleum Inc | Denver, CO 80202 | Oil & Gas Operator | Jan 2019 |
| 370 | Af Operating, LLC | | Oil Operator | Sep 2012 |
| 371 | Afco Energy Prod Co | Indiana, PA 15701-0538 | Oil & Gas Operator | Dec 2016 |
| 372 | Afe Management Limited | Concord, Ontario, L4K 4G4 | Oil & Gas Operator | Sep 1987 |
| 373 | Afe Oil & Gas Consultants | | Gas Operator | Jan 2003 |
| 374 | Affiliated Holdings, Inc. | | Oil & Gas Operator | Sep 2014 |
| 375 | Afg Energy, Inc. | Houston, TX 77002 | Oil & Gas Operator | Dec 2009 |
| 376 | Afo LLC | Velma, OK 73491-0155 | Oil Operator | Dec 2015 |
| 377 | Agape Energy Inc. | | Oil Operator | Feb 2019 |
| 378 | Agape Inc | Broken Arrow, OK 74011-4256 | Oil Operator | Nov 2015 |
| 379 | Agape Service Incorporated | Denver, CO 80201 | Gas Operator | Nov 2018 |
| 380 | Agate Petroleum, Inc. | Tulsa, OK 74136-5741 | Oil & Gas Operator | Aug 2015 |
| 381 | Agave Energy Inc | Stigler, OK 74462 | Gas Operator | Dec 2018 |
| 382 | Agave Operating Company, Inc. | Holliday, TX 76366 | Oil Operator | Feb 2019 |
| 383 | Ageron Energy, LLC | San Antonio, TX 78209 | Oil & Gas Operator | Feb 2019 |
| 384 | Agey Petroleum Company | | Oil & Gas Operator | Dec 1998 |
| 385 | Aggietech Oil, LTD. | Midland, TX 79701 | Oil & Gas Operator | Aug 2016 |
| 386 | Aghorn Operating, Inc. | Odessa, TX 79768 | Oil & Gas Operator | Feb 2019 |
| 387 | Agip Petroleum Co., Inc. | | Oil & Gas Operator | Jan 2003 |
| 388 | Agnew-Sullivan Inc | | Oil Operator | Dec 2003 |
| 389 | Agon Oil Company, LLC | Big Spring, TX 79721 | Oil Operator | Feb 2019 |
| 390 | Agricultural Energy Services | Edmond, OK 73003 | Oil & Gas Operator | Nov 2018 |
| 391 | Agricultural Energy Services Inc | Edmond, OK 73003-0032 | Gas Operator | Dec 2018 |
| 392 | Agroil, Inc. | | Oil & Gas Operator | Feb 2019 |
| 393 | Agua Sucia LLC | Lovington, NM 88260 | Oil & Gas Operator | Jul 2018 |
| 394 | Agv Corp. | Attica, KS 67009 | Oil & Gas Operator | Nov 2018 |
| 395 | Ahabb Oil | | Oil & Gas Operator | Dec 1998 |
| 396 | Aiello Bros Oil & Gas Inc | Bradford, PA 16701-2925 | Oil & Gas Operator | Dec 2018 |
| 397 | Aikins Drilling Company | Mohave Valley, AZ 86440 | Oil Operator | Dec 2018 |
| 398 | Aikman Brothers | Midland, TX 79705 | Gas Operator | Apr 1996 |
| 399 | Aikman Brothers, LLC | Amarillo, TX 79109 | Oil & Gas Operator | Dec 2018 |
| 400 | Aikman Oil Corp. | Oklahoma City, OK 73157-2922 | Oil & Gas Operator | Feb 2019 |