| 501 | Kersey & Company | Ellijay, GA 30540 | Oil & Gas Operator | Jan 2023 |
| 502 | Kestrel Energy Inc | Lakewood, CO 80401 | Oil & Gas Operator | Jan 2008 |
| 503 | Kestrel Resources, Inc. | Dallas, TX 75204 | Oil & Gas Operator | Sep 2015 |
| 504 | Ketal Oil Producing Company | Fort Worth, TX 76102 | Gas Operator | Sep 1995 |
| 505 | Ketcham VIctor A | Columbus, OH 43214 | Oil Operator | Dec 2021 |
| 506 | Kettlebrook Energy, Inc. | Westfield, NY 14787 | Gas Operator | Dec 2024 |
| 507 | Kevin O Butler & Assoc Inc | Midland, TX 79702 | Oil & Gas Operator | Dec 2025 |
| 508 | Kewanee Oil Comp | | Oil & Gas Operator | Nov 1996 |
| 509 | Kewanee Oil Company | Houston, TX 77001 | Oil & Gas Operator | Aug 1978 |
| 510 | Key Energy Corporation | Enid, OK 73702-5349 | Oil & Gas Operator | Oct 2017 |
| 511 | Key Energy Of Colorado, Inc. | Tulsa, OK 74103 | Oil & Gas Operator | Jun 2016 |
| 512 | Key Energy Services Inc | Midland, TX 79705-5540 | Oil Operator | Jan 2008 |
| 513 | Key Energy Services, Inc.Altd | | Oil Operator | Dec 2006 |
| 514 | Key Energy Services, LLC | Houston, TX 77042 | Oil Operator | Jan 2025 |
| 515 | Key Gas Corp. | Wichita, KS 67202 | Oil & Gas Operator | Nov 2018 |
| 516 | Key Oil Company | Duncan, OK 73533 | Oil & Gas Operator | Dec 2021 |
| 517 | Key Operating & Equipment, Inc. | Midlothian, TX 76065 | Oil & Gas Operator | Nov 2024 |
| 518 | Key Operating Company Inc | Duncan, OK 73534-1284 | Oil & Gas Operator | Jan 2025 |
| 519 | Key Petroleum Inc. | Houston, TX 77056 | Oil & Gas Operator | Aug 2003 |
| 520 | Key Production Company, Inc. | Longview, TX 75606 | Oil & Gas Operator | Nov 2025 |
| 521 | Key, J. J. | Lubbock, TX 79416 | Oil & Gas Operator | Feb 2026 |
| 522 | Keybank National Association, Trustee | Brooklyn, OH 44144 | Gas Operator | Dec 2024 |
| 523 | Keyrock Energy LLC | Johnson City, TN 37604-5749 | Oil & Gas Operator | Dec 2024 |
| 524 | Keys Gerald W Oi | | Oil Operator | Mar 1993 |
| 525 | Keys, Gerald Oil Production & Explor. | Humboldt, KS 66748 | Oil Operator | Mar 1999 |
| 526 | Keyse, Ralph L. | Lane, KS 66042 | Oil Operator | Jul 2018 |
| 527 | Keystate Inc | Davidsville, PA 15928-9655 | Gas Operator | Dec 2012 |
| 528 | Keystone Acquisitions LLC | Anita, PA 15711-9747 | Gas Operator | Dec 2025 |
| 529 | Keystone Energy LLC | Farmington, NM 87499 | Oil & Gas Operator | Dec 2025 |
| 530 | Keystone Energy Oil & Gas Inc | Pittsburgh, PA 15222 | Oil & Gas Operator | Dec 2016 |
| 531 | Keystone Exploration, Inc | College Sta, TX 77845 | Oil & Gas Operator | Feb 2026 |
| 532 | Keystone Fuel Oil Co | | Gas Operator | Nov 1997 |
| 533 | Keystone Land Resources Inc | St Clairsville, OH 43950 | Oil & Gas Operator | Dec 2025 |
| 534 | Keystone Oil And Gas Company LLC | Collinsville, OK 74021 | Oil & Gas Operator | Nov 2025 |
| 535 | Keystone Oil Co. | Eureka, KS 67045 | Oil Operator | May 2000 |
| 536 | Keystone Operating Co. | Round Rock, TX 78681 | Oil & Gas Operator | Feb 2026 |
| 537 | Keystone Petroleum GP LLC | Irving, TX 75039 | Oil & Gas Operator | May 2012 |
| 538 | Keystone Petroleum NM LLC | Irving, TX 75039 | Oil & Gas Operator | Jan 2016 |
| 539 | Keystone Production Company | Duncan, OK 73533-9117 | Oil & Gas Operator | May 2005 |
| 540 | Keystone Productions, LLC | | Gas Operator | Dec 2024 |
| 541 | Keystone Resources Inc | Cranberry Township, PA 16066-6446 | Gas Operator | Dec 1992 |
| 542 | Keyway Oil & Gas Operating LLC | Kilgore, TX 75663 | Oil Operator | Oct 2020 |
| 543 | KFG Petroleum Corporation | | Oil & Gas Operator | Dec 2025 |
| 544 | KFS Investments, L.L.C. | | Oil & Gas Operator | Jul 2009 |
| 545 | KG Oil Co | | Oil Operator | Aug 2025 |
| 546 | Kga Oil Company, Inc. | High Island, TX 77623 | Oil & Gas Operator | Aug 2004 |
| 547 | KGH Operating Company | Billings, MT 59115 | Oil & Gas Operator | Nov 2025 |
| 548 | Kiamichi Oil & Gas | Whitehouse, TX 75791 | Oil Operator | Oct 1997 |
| 549 | Kiamichi Resources Inc | Oklahoma City, OK 73143 | Oil & Gas Operator | Feb 2016 |
| 550 | Kiawah Resources, LLC | Houston, TX 77056 | Oil & Gas Operator | Nov 2017 |
| 551 | Kibbe, Anna S. | Falfurrias, TX 78355 | Oil & Gas Operator | Sep 1998 |
| 552 | Kibtec Oil & Gas Inc | Cashion, OK 73016 | Oil & Gas Operator | Aug 2024 |
| 553 | Kickapoo Oil Co | Baton Rouge, LA 70815 | Gas Operator | Feb 1994 |
| 554 | Kidd Bill R | Bristow, OK 74010-9721 | Oil Operator | Jan 2013 |
| 555 | Kidd Charlie Drilling | Utica, OH 43080 | Oil & Gas Operator | Dec 2002 |
| 556 | Kidd Johnson Oil & Gas | San Angelo, TX 76904 | Oil & Gas Operator | Feb 2013 |
| 557 | Kidd Johnson Oil & Gas, LLC | San Angelo, TX 76904 | Oil & Gas Operator | Feb 2026 |
| 558 | Kidd Oil & Gas, LC | Dallas, TX 75219 | Oil & Gas Operator | Apr 1999 |
| 559 | Kidd Production Co. | Luling, TX 78648 | Oil & Gas Operator | Feb 2026 |
| 560 | Kidd William E Production | Gambier, OH 43022 | Oil & Gas Operator | Dec 1993 |
| 561 | Kidder Exploration Inc | Jamestown, NY 14701-5613 | Gas Operator | Dec 1991 |
| 562 | Kidder, Bruce | Jamestown, NY 14701 | Gas Operator | Dec 2024 |
| 563 | Kids Future, L.L.C. | Bivins, TX 75555 | Oil Operator | Feb 2026 |
| 564 | Kiefer Oil And Gas Co Inc | Sapulpa, OK 74066 | Oil & Gas Operator | Apr 2011 |
| 565 | Kienzle John A | Shawnee, OK 74802-1265 | Oil & Gas Operator | Aug 2013 |
| 566 | Kiesling Oil Company | Osage, WY 82723 | Oil & Gas Operator | Oct 2007 |
| 567 | Kiester Operating Company | Oklahoma City, OK 73106 | Oil & Gas Operator | Nov 2025 |
| 568 | Kilbarger Investments Inc | Logan, OH 43138 | Oil & Gas Operator | Dec 2024 |
| 569 | Kilby Oil Producer | Wichita, KS 67210 | Gas Operator | Sep 1997 |
| 570 | Kilby, M. T. | Yates Center, KS 66783 | Oil Operator | Sep 1986 |
| 571 | Kilco, Inc. | | Gas Operator | Sep 1996 |
| 572 | Kile Production | Cypress, TX 77410 | Oil & Gas Operator | Aug 2014 |
| 573 | Killam Oil Co., LTD. | Laredo, TX 78042 | Oil & Gas Operator | Feb 2026 |
| 574 | Killam Oil Company | Laredo, TX 78042 | Oil & Gas Operator | Mar 1994 |
| 575 | Killbuck Creek Oil Co LLC | Wooster, OH 44691 | Oil & Gas Operator | Dec 2024 |
| 576 | Killbuck Oilfield Service | Killbuck, OH 44637 | Oil & Gas Operator | Dec 2022 |
| 577 | Killer Rabbit Fields LLC | Monahans, TX 79756 | Oil & Gas Operator | Feb 2026 |
| 578 | Killian, Jeffrey M | Bowling Green, KY 42101 | Oil & Gas Operator | Dec 2023 |
| 579 | Killingsworth Oil Co. | Longview, TX 75606 | Oil & Gas Operator | Feb 2026 |
| 580 | Killingsworth, Lee Operator | Longview, TX 75601 | Oil & Gas Operator | Jan 1999 |
| 581 | Killion Well Service Inc. | Breckenridge, TX 76424 | Oil & Gas Operator | Dec 2014 |
| 582 | Kilmarnock Oil Company, Inc. | Corsicana, TX 75110 | Oil & Gas Operator | Feb 2026 |
| 583 | Kilpatrick Production Company | Tye, TX 79563 | Oil & Gas Operator | Feb 2026 |
| 584 | Kilroy Co. Of Texas, Inc. | | Oil & Gas Operator | Jun 1991 |
| 585 | Kilroy Co.- E.L. Cox | | Oil & Gas Operator | Aug 1990 |
| 586 | Kim Ray Oil & Gas | Ada, OK 74820 | Oil & Gas Operator | Nov 2025 |
| 587 | Kimball Production Co. | Houston, TX 77042 | Oil & Gas Operator | Jul 2002 |
| 588 | Kimbark Oil & Ga | | Oil & Gas Operator | Aug 1992 |
| 589 | Kimbark Oil & Gas Company | Denver, CO 80203 | Oil & Gas Operator | May 2007 |
| 590 | Kimbell Oil Company Of Texas | Fort Worth, TX 76102 | Oil & Gas Operator | Dec 2025 |
| 591 | Kimbell Operating Company | Fort Worth, TX 76102 | Oil & Gas Operator | Feb 2026 |
| 592 | Kimberlin & Huitt | Jacksboro, TX 76458 | Oil & Gas Operator | Feb 1998 |
| 593 | Kimberlin & Miller | Dallas, TX 75230 | Oil & Gas Operator | Feb 2026 |
| 594 | Kimberlin Energy Group | Dallas, TX 75235 | Oil & Gas Operator | Feb 2026 |
| 595 | Kimble Oil Company, Inc. | Breckenridge, TX 76424 | Oil & Gas Operator | Jun 2006 |
| 596 | Kimbrel Oil Corporation | Tulsa, OK 74114 | Oil & Gas Operator | Feb 2026 |
| 597 | Kimbrough Engineering Co, LLC | New Braunfels, TX 78132 | Oil & Gas Operator | Dec 2014 |
| 598 | Kimbrough Oil Company | Iraan, TX 79744 | Oil Operator | Feb 2026 |
| 599 | Kimbrough, D. E. | Iraan, TX 79744 | Oil & Gas Operator | Feb 2026 |
| 600 | Kimco Energy Corporation | | Oil & Gas Operator | Apr 1989 |