| 501 | Alinet Corporation | | Oil & Gas Operator | Oct 2017 |
| 502 | All Am, Inc. | | Gas Operator | Feb 2016 |
| 503 | All Exploration LLC | Oklahoma City, OK 73120-7829 | Oil & Gas Operator | Dec 2018 |
| 504 | All In Energy Production, LLP | Red Rock, TX 78662 | Oil Operator | Feb 2019 |
| 505 | All State Energy Corp. | | Oil & Gas Operator | Dec 2017 |
| 506 | All States Oil & Producing Co | Canton, OH 44702 | Oil & Gas Operator | Dec 2018 |
| 507 | All-Southwest Petroleum, Inc. | | Oil & Gas Operator | Oct 1997 |
| 508 | Allam Carl Oil C | | Oil Operator | Mar 1986 |
| 509 | Allam Kevin T Oi | | Oil Operator | Jun 1988 |
| 510 | Allam Production, Inc. | Hutchinson, KS 67504 | Oil & Gas Operator | Nov 2018 |
| 511 | Allam WM Robt Jr | | Oil Operator | Aug 1993 |
| 512 | Allar Co., The | Graham, TX 76450 | Oil & Gas Operator | Dec 2004 |
| 513 | Alleder Inc. | Midland, TX 79702 | Oil & Gas Operator | Feb 2019 |
| 514 | Allegany Yankee Holdings LTD | Wellsville, NY 14895 | Oil & Gas Operator | Dec 2017 |
| 515 | Allegheny & Western Energy Corp | | Oil & Gas Operator | Dec 2017 |
| 516 | Allegheny Enterprises Inc | Corsica, PA 15829-3833 | Oil & Gas Operator | Dec 2018 |
| 517 | Allegheny Natural Resources Inc | Sewickley, PA 15143-8676 | Gas Operator | Dec 2017 |
| 518 | Allegheny Producers Inc | Cambridge, OH 43725 | Oil & Gas Operator | Dec 1984 |
| 519 | Allegro Investments, Inc. | Victoria, TX 77903-4085 | Oil & Gas Operator | Feb 2019 |
| 520 | Allegro Operating, Inc. | | Oil & Gas Operator | Feb 2019 |
| 521 | Allen & Grace Oil Company | | Oil & Gas Operator | Jul 1997 |
| 522 | Allen & Shumate, Inc. | | Oil & Gas Operator | Jan 1996 |
| 523 | Allen And Crouch | | Oil & Gas Operator | Dec 2018 |
| 524 | Allen And Schramm Inc | | Oil & Gas Operator | Dec 1989 |
| 525 | Allen Brothers | | Oil & Gas Operator | Aug 2018 |
| 526 | Allen Brothers Company | Oil City, LA 71061 | Oil & Gas Operator | Apr 1997 |
| 527 | Allen Drilling C | | Oil & Gas Operator | Nov 1994 |
| 528 | Allen Drilling Company | Great Bend, KS 67530 | Oil & Gas Operator | Dec 2009 |
| 529 | Allen J D & Comp | | Oil Operator | Jan 1983 |
| 530 | Allen K Trobaugh | Midland, TX 79705 | Oil & Gas Operator | Mar 1997 |
| 531 | Allen Mabel C | Dublin, OH 43017 | Oil Operator | Dec 1988 |
| 532 | Allen Michael | Broken Arrow, OK 74014-2239 | Oil & Gas Operator | Dec 2015 |
| 533 | Allen Operating Company, LLC | Natchez, MS 39121 | Oil & Gas Operator | Dec 2018 |
| 534 | Allen Petroleum Company | | Oil Operator | Apr 1996 |
| 535 | Allen Petroleum Services Inc. | Natchez, MS 39121 | Gas Operator | Aug 2000 |
| 536 | Allen Petroleum, Inc. | | Oil Operator | Jul 2010 |
| 537 | Allen, C. L. (Doie) | Nocona, TX 76255 | Oil & Gas Operator | Feb 2019 |
| 538 | Allen, Mabel F. | | Oil & Gas Operator | Jul 2002 |
| 539 | Allenco Energy, Inc. | Signal Hill, CA 90755-3517 | Oil & Gas Operator | Dec 2017 |
| 540 | Allenergy Operating Co Inc | Coffeyville, KS 67337-6653 | Oil & Gas Operator | Aug 2015 |
| 541 | Allenergy, Inc. | Grove, OK 74345 | Oil & Gas Operator | Jul 2012 |
| 542 | Alliance Exploration Co., LLC | Tulsa, OK 74119 | Oil Operator | Apr 2017 |
| 543 | Alliance Exploration Corp. | | Oil & Gas Operator | Mar 1983 |
| 544 | Alliance Oil & Gas Co Inc | Corinth, TX 76205 | Oil & Gas Operator | Mar 2015 |
| 545 | Alliance Operating Corporation | | Oil & Gas Operator | Jan 1995 |
| 546 | Alliance Petroleum Corporation | Canton, OH 44718-2553 | Oil & Gas Operator | Dec 2018 |
| 547 | Alliance Resources (USA), Inc. | | Oil & Gas Operator | Oct 2002 |
| 548 | Alliance Resources Corporation | Dallas, TX 75367-249 | Oil & Gas Operator | Feb 2019 |
| 549 | Allied Energy Corporation | | Oil & Gas Operator | Dec 2007 |
| 550 | Allied Energy, Inc. | Belpre, OH 45714- 000 | Oil & Gas Operator | Dec 2017 |
| 551 | Allied Exploration, Inc. | | Oil & Gas Operator | Oct 2018 |
| 552 | Allied Materials Corp | Oklahoma City, OK 73157-2340 | Gas Operator | Dec 2009 |
| 553 | Allied Oil Compa | | Oil & Gas Operator | Feb 1995 |
| 554 | Allied Oil Company, Inc. | Taneyville, MO 65759 | Oil Operator | Apr 1996 |
| 555 | Allied Oil Field Services LTD | Willoughby, OH 44094 | Oil & Gas Operator | Dec 2018 |
| 556 | Allied Operating LLC | Bowling Green, KY 42101-3980 | Oil & Gas Operator | Nov 2015 |
| 557 | Allied Operating Texas, LLC | Kilgore, TX 75663 | Oil & Gas Operator | Feb 2019 |
| 558 | Allied Petroleum Company | | Gas Operator | Jan 1992 |
| 559 | Allied Western Petroleum | Tiburon, CA 94920 | Oil & Gas Operator | Feb 2017 |
| 560 | Allied-Gulf Energy, LLC | Lafayette, LA 70508 | Oil & Gas Operator | Feb 2019 |
| 561 | Allison Bros DRLG Co Inc | | Oil & Gas Operator | Dec 2015 |
| 562 | Allison Dean Oil | | Oil & Gas Operator | Nov 1994 |
| 563 | Allison J A | | Oil & Gas Operator | Nov 1995 |
| 564 | Allison Oil Comp | | Oil Operator | Dec 1986 |
| 565 | Allison Operating Co., L.C. | Wichita, KS 67202 | Oil & Gas Operator | Dec 1998 |
| 566 | Allison/Hobbs Inc. | Alba, TX 75410-5796 | Oil & Gas Operator | Feb 2019 |
| 567 | Allsop Oil And Gas Company, Inc. | | Oil & Gas Operator | Nov 1996 |
| 568 | Allstar Oil And Gas Inc. | Tickfaw, LA 70466 | Oil & Gas Operator | Nov 1992 |
| 569 | Alltex Exploration, Inc. | Houston, TX 77056-4390 | Oil & Gas Operator | Feb 2019 |
| 570 | Alltex Operating Company | Houston, TX 77269 | Oil & Gas Operator | Feb 2019 |
| 571 | Alma Gas Co Inc | Olean, NY 14760-9309 | Gas Operator | Dec 2017 |
| 572 | Alma Gas, Inc. | Olean, NY 14760 | Gas Operator | Dec 2017 |
| 573 | Alme, Henry A. | Cut Bank, MT 59427 | Gas Operator | Oct 2018 |
| 574 | Almont Energy LLC | | Oil & Gas Operator | Sep 2018 |
| 575 | Alna Energy LLC | New Lexington, OH 43764 | Oil & Gas Operator | Dec 2017 |
| 576 | Alog, LLC | Brewton, AL 36427 | Oil & Gas Operator | Dec 2018 |
| 577 | Alon Bakersfield Property Inc. | Bakersfield, CA 93308 | Oil & Gas Operator | Feb 2018 |
| 578 | Alpar Resources, Inc. | Perryton, TX 79070-906 | Oil & Gas Operator | Aug 2018 |
| 579 | Alpha Coal West Inc | | Oil & Gas Operator | Dec 2018 |
| 580 | Alpha Energy | | Oil & Gas Operator | Oct 2016 |
| 581 | Alpha Energy, LLC | Overland Park, KS 66206 | Oil Operator | Dec 2009 |
| 582 | Alpha Exploration Co. | | Oil & Gas Operator | Oct 1998 |
| 583 | Alpha Gamma Onshore, LLC | Midland, TX 79702 | Oil Operator | Feb 2019 |
| 584 | Alpha Gas Corporation | Jane Lew, WV 26378 | Oil & Gas Operator | Dec 2014 |
| 585 | Alpha Management | | Oil & Gas Operator | Jan 1994 |
| 586 | Alpha Oil & Gas Inc. | | Oil & Gas Operator | Sep 1989 |
| 587 | Alpha Omega Petroleum, Inc. | | Oil & Gas Operator | Mar 1996 |
| 588 | Alpha Petroleum | | Oil & Gas Operator | Sep 2018 |
| 589 | Alpha Petrovision Us Inc | Canada, 100 | Oil & Gas Operator | May 2013 |
| 590 | Alpha Resources, Inc | | Oil & Gas Operator | Jun 2003 |
| 591 | Alpha Shale Res LP | Canonsburg, PA 15317 | Gas Operator | Aug 2017 |
| 592 | Alphin, Don R | El Dorado, AR 71730 | Oil Operator | Jan 2019 |
| 593 | Alpine Drilling | | Oil & Gas Operator | May 1994 |
| 594 | Alpine Drilling Company, Inc. | Wichita, KS 67202 | Oil & Gas Operator | Apr 2000 |
| 595 | Alpine Energy Corp. | | Oil & Gas Operator | Jun 2004 |
| 596 | Alpine Energy, Inc. | | Oil & Gas Operator | Dec 1999 |
| 597 | Alpine Expl. Companies, Inc. | | Oil & Gas Operator | Sep 2018 |
| 598 | Alpine Exploration Co, Inc. | Dallas, TX 75360-13 | Oil & Gas Operator | Nov 2017 |
| 599 | Alpine Gas Company, LLC | | Oil & Gas Operator | Oct 2006 |
| 600 | Alpine Gas Operator, LLC | Dallas, TX 75201 | Oil & Gas Operator | Dec 2018 |