| 501 | Alfaro Oil & Gas | Burkburnett, TX 76354 | Oil & Gas Operator | Jan 2019 |
| 502 | Alfaro Production LLC | Burkburnett, TX 76354 | Oil Operator | Jan 2019 |
| 503 | Alford Josh Enterprises | | Gas Operator | Sep 2018 |
| 504 | Alfred C. Glassell, Jr. | | Oil & Gas Operator | Apr 2007 |
| 505 | Alfred Lamson-James A. Crocker | | Oil & Gas Operator | Sep 1986 |
| 506 | Alfred, Dewayne L | Weston, WV 26542-0478 | Oil & Gas Operator | Dec 1996 |
| 507 | Algoa Operating Company, LLC | Houston, TX 77077 | Oil & Gas Operator | Sep 2002 |
| 508 | Alice & Andrew & George Hazer | Girard, PA 16417-9801 | Gas Operator | Dec 2017 |
| 509 | Alinet Corporation | | Oil & Gas Operator | Oct 2017 |
| 510 | All Am, Inc. | | Gas Operator | Feb 2016 |
| 511 | All Exploration LLC | Oklahoma City, OK 73120-7829 | Oil & Gas Operator | Oct 2018 |
| 512 | All In Energy Production, LLP | Red Rock, TX 78662 | Oil Operator | Jan 2019 |
| 513 | All Oil & Gas Inc. | | Oil & Gas Operator | Jul 1989 |
| 514 | All State Energy Corp. | | Oil & Gas Operator | Dec 2017 |
| 515 | All States Oil & Prod | Canton, OH 44702 | Oil & Gas Operator | Dec 2018 |
| 516 | All-Southwest Petroleum, Inc. | | Oil & Gas Operator | Oct 1997 |
| 517 | Allam Carl Oil C | | Oil Operator | Mar 1986 |
| 518 | Allam Kevin T Oi | | Oil Operator | Jun 1988 |
| 519 | Allam Production, Inc. | Hutchinson, KS 67504 | Oil & Gas Operator | Sep 2018 |
| 520 | Allam WM Robt Jr | | Oil Operator | Aug 1993 |
| 521 | Allar Co., The | Graham, TX 76450 | Oil & Gas Operator | Dec 2004 |
| 522 | Alleder Inc. | Midland, TX 79702 | Oil & Gas Operator | Jan 2019 |
| 523 | Allegany Yankee Holdings LTD | Wellsville, NY 14895 | Oil & Gas Operator | Dec 2017 |
| 524 | Allegheny & Western Energy Corp | | Oil & Gas Operator | Dec 2017 |
| 525 | Allegheny Enterprises Inc | Corsica, PA 15829-3833 | Oil & Gas Operator | Dec 2017 |
| 526 | Allegheny Natural Resources Inc | Sewickley, PA 15143-8676 | Gas Operator | Dec 2017 |
| 527 | Allegheny Producers Inc | Cambridge, OH 43725 | Oil & Gas Operator | Dec 1984 |
| 528 | Allegro Investments, Inc. | Victoria, TX 77903-4085 | Oil & Gas Operator | Jan 2019 |
| 529 | Allegro Operating, Inc. | | Oil & Gas Operator | Jan 2019 |
| 530 | Allen & Grace Oil Company | | Oil & Gas Operator | Jul 1997 |
| 531 | Allen & Shumate, Inc. | | Oil & Gas Operator | Jan 1996 |
| 532 | Allen And Crouch | | Oil & Gas Operator | Dec 2018 |
| 533 | Allen And Schramm Inc | | Oil & Gas Operator | Dec 1989 |
| 534 | Allen Brothers | | Oil & Gas Operator | Aug 2018 |
| 535 | Allen Brothers Company | Oil City, LA 71061 | Oil & Gas Operator | Apr 1997 |
| 536 | Allen Drilling C | | Oil & Gas Operator | Nov 1994 |
| 537 | Allen Drilling Company | Great Bend, KS 67530 | Oil & Gas Operator | Dec 2009 |
| 538 | Allen J D & Comp | | Oil Operator | Jan 1983 |
| 539 | Allen K Trobaugh | Midland, TX 79705 | Oil & Gas Operator | Mar 1997 |
| 540 | Allen Mabel C | Dublin, OH 43017 | Oil Operator | Dec 1988 |
| 541 | Allen Michael | Broken Arrow, OK 74014-2239 | Oil & Gas Operator | Dec 2015 |
| 542 | Allen Operating Company, LLC | Natchez, MS 39121 | Oil & Gas Operator | Oct 2018 |
| 543 | Allen Petroleum Company | | Oil Operator | Apr 1996 |
| 544 | Allen Petroleum Services Inc. | Natchez, MS 39121 | Gas Operator | Aug 2000 |
| 545 | Allen Petroleum, Inc. | | Oil Operator | Jul 2010 |
| 546 | Allen, C. L. (Doie) | Nocona, TX 76255 | Oil & Gas Operator | Jan 2019 |
| 547 | Allen, Mabel F. | | Oil & Gas Operator | Jul 2002 |
| 548 | Allenco Energy, Inc. | Signal Hill, CA 90755-3517 | Oil & Gas Operator | Dec 2017 |
| 549 | Allenergy Operating Co Inc | Coffeyville, KS 67337-6653 | Oil & Gas Operator | Aug 2015 |
| 550 | Allenergy, Inc. | Grove, OK 74345 | Oil & Gas Operator | Jul 2012 |
| 551 | Allgood Oil And Gas, LLC | Euless, TX 76040 | Oil Operator | Jan 2019 |
| 552 | Alliance Exploration Co., LLC | Tulsa, OK 74119 | Oil Operator | Apr 2017 |
| 553 | Alliance Exploration Corp. | | Oil & Gas Operator | Mar 1983 |
| 554 | Alliance Ogo, LP | Pleasanton, CA 94588 | Oil & Gas Operator | Jan 2019 |
| 555 | Alliance Oil & Gas Co Inc | Corinth, TX 76205 | Oil & Gas Operator | Mar 2015 |
| 556 | Alliance Operating Corporation | | Oil & Gas Operator | Jan 1995 |
| 557 | Alliance Petroleum Corporation | Canton, OH 44718-2553 | Oil & Gas Operator | Oct 2018 |
| 558 | Alliance Resources (USA), Inc. | | Oil & Gas Operator | Oct 2002 |
| 559 | Alliance Resources Corporation | Dallas, TX 75367-249 | Oil & Gas Operator | Jan 2019 |
| 560 | Allied Energy Corporation | | Oil & Gas Operator | Dec 2007 |
| 561 | Allied Energy, Inc. | Belpre, OH 45714- 000 | Oil & Gas Operator | Dec 2017 |
| 562 | Allied Exploration, Inc. | | Oil & Gas Operator | Oct 2018 |
| 563 | Allied Materials Corp | Oklahoma City, OK 73157-2340 | Gas Operator | Dec 2009 |
| 564 | Allied Oil Compa | | Oil & Gas Operator | Feb 1995 |
| 565 | Allied Oil Company, Inc. | Taneyville, MO 65759 | Oil Operator | Apr 1996 |
| 566 | Allied Oil Field Services LTD | Willoughby, OH 44094 | Oil & Gas Operator | Dec 2017 |
| 567 | Allied Operating LLC | Bowling Green, KY 42101-3980 | Oil & Gas Operator | Nov 2015 |
| 568 | Allied Operating Texas, LLC | Kilgore, TX 75663 | Oil & Gas Operator | Jan 2019 |
| 569 | Allied Petroleum Company | | Gas Operator | Jan 1992 |
| 570 | Allied Western Petroleum | Tiburon, CA 94920 | Oil & Gas Operator | Feb 2017 |
| 571 | Allied-Gulf Energy, LLC | Lafayette, LA 70505 | Oil & Gas Operator | Jan 2019 |
| 572 | Alligator Rock Well Service LLC | | Gas Operator | Oct 2018 |
| 573 | Allison Bros DRLG Co Inc | | Oil & Gas Operator | Dec 2015 |
| 574 | Allison Dean Oil | | Oil & Gas Operator | Nov 1994 |
| 575 | Allison J A | | Oil & Gas Operator | Nov 1995 |
| 576 | Allison Oil Comp | | Oil Operator | Dec 1986 |
| 577 | Allison Operating Co., L.C. | Wichita, KS 67202 | Oil & Gas Operator | Dec 1998 |
| 578 | Allison/Hobbs Inc. | Alba, TX 75410-5796 | Oil & Gas Operator | Jan 2019 |
| 579 | Allsop Oil And Gas Company, Inc. | | Oil & Gas Operator | Nov 1996 |
| 580 | Allstar Oil And Gas Inc. | Tickfaw, LA 70466 | Oil & Gas Operator | Nov 1992 |
| 581 | Alltex Exploration, Inc. | Houston, TX 77056-4390 | Oil & Gas Operator | Jan 2019 |
| 582 | Alltex Operating Company | Houston, TX 77269 | Oil & Gas Operator | Jan 2019 |
| 583 | Alma Gas Co Inc | Olean, NY 14760-9309 | Gas Operator | Dec 2017 |
| 584 | Alma Gas, Inc. | Olean, NY 14760 | Gas Operator | Dec 2017 |
| 585 | Alme, Henry A. | Cut Bank, MT 59427 | Gas Operator | Sep 2018 |
| 586 | Almont Energy LLC | | Oil & Gas Operator | Nov 2018 |
| 587 | Alna Energy LLC | New Lexington, OH 43764 | Oil & Gas Operator | Dec 2017 |
| 588 | Alog, LLC | Brewton, AL 36427 | Oil & Gas Operator | Sep 2018 |
| 589 | Alon Bakersfield Property Inc. | Bakersfield, CA 93308 | Oil & Gas Operator | Feb 2018 |
| 590 | Alpar Resources, Inc. | Perryton, TX 79070-906 | Oil & Gas Operator | Aug 2018 |
| 591 | Alpha Coal West Inc | | Oil & Gas Operator | Dec 2018 |
| 592 | Alpha Energy | | Oil & Gas Operator | Oct 2016 |
| 593 | Alpha Energy, LLC | Overland Park, KS 66206 | Oil Operator | Dec 2009 |
| 594 | Alpha Exploration Co. | | Oil & Gas Operator | Oct 1998 |
| 595 | Alpha Gamma Onshore, LLC | Midland, TX 79702 | Oil Operator | Jan 2019 |
| 596 | Alpha Gas Corporation | Jane Lew, WV 26378 | Oil & Gas Operator | Dec 2014 |
| 597 | Alpha Management | | Oil & Gas Operator | Jan 1994 |
| 598 | Alpha Oil & Gas Inc. | | Oil & Gas Operator | Sep 1989 |
| 599 | Alpha Omega Petroleum, Inc. | | Oil & Gas Operator | Mar 1996 |
| 600 | Alpha Petroleum | | Oil & Gas Operator | Sep 2018 |