| 21501 | Nytis Exploration Company LLC | Lexington, KY 40509 | Oil & Gas Operator | Dec 2021 |
| 21502 | NZ Operating Company Inc. | Houston, TX 77069 | Oil & Gas Operator | Feb 2026 |
| 21503 | O & G Energy, Inc. | Abilene, TX 79608 | Oil & Gas Operator | Oct 1996 |
| 21504 | O & O Operators, LLC. | Fate, TX 75132 | Oil & Gas Operator | Feb 2026 |
| 21505 | O G & E | Oklahoma City, OK 73124 | Oil & Gas Operator | Feb 2014 |
| 21506 | O H Berry | Midland, TX 79702 | Oil & Gas Operator | Feb 2003 |
| 21507 | O Hill Enterprises, Inc. | La Grange, TX 78945 | Oil & Gas Operator | Jan 2014 |
| 21508 | O I L Energy Corp | | Oil Operator | Dec 2016 |
| 21509 | O I L Niagaran LLC | | Oil Operator | Dec 2016 |
| 21510 | O K Swabbing Inc | Hennessey, OK 73742 | Oil & Gas Operator | Nov 2025 |
| 21511 | O S & J Operatin | | Oil Operator | Nov 1984 |
| 21512 | O S & S Oil Company | Electra, TX 76360 | Oil & Gas Operator | Jan 2018 |
| 21513 | O&Apos;Brien Energy Resources Corp | | Oil & Gas Operator | Dec 2024 |
| 21514 | O&G Investments Inc. | Runge, TX 78151 | Oil & Gas Operator | Feb 2003 |
| 21515 | O'Bar Operating Co., Inc. | Longview, TX 75604 | Oil & Gas Operator | Feb 2026 |
| 21516 | O'Benco, Inc. | Shreveport, LA 71136 | Oil & Gas Operator | Feb 2026 |
| 21517 | O'Blue Corp. | Kerrville, TX 78028 | Oil & Gas Operator | Mar 1998 |
| 21518 | O'Boyle Energy Corporation | | Oil Operator | Feb 1991 |
| 21519 | O'Brien Energy Company | Shreveport, LA 71136 | Oil & Gas Operator | Sep 2019 |
| 21520 | O'Brien Energy Resources Corp | Portsmouth, NH 03801 | Oil & Gas Operator | Feb 2026 |
| 21521 | O'Brien Oil Corporation | Guthrie, OK 73044-3154 | Oil & Gas Operator | Nov 2025 |
| 21522 | O'Brien Oil LLC | Guthrie, OK 73044-3154 | Oil & Gas Operator | Apr 2020 |
| 21523 | O'Brien Operating Company | Shreveport, LA 71164 | Oil & Gas Operator | Dec 2004 |
| 21524 | O'Brien Resources LLC | Shreveport, LA 71136 | Oil Operator | Nov 2017 |
| 21525 | O'Brien, George H. Jr. | Midland, TX 79701 | Oil & Gas Operator | Jun 1994 |
| 21526 | O'Brien, Mae Or Brett Strickland | Belington, WV 26250-0076 | Oil & Gas Operator | Dec 2021 |
| 21527 | O'Brien-Sill | | Oil & Gas Operator | Dec 2025 |
| 21528 | O'Connell, James P. | Vacaville, CA 95687 | Oil Operator | Nov 2009 |
| 21529 | O'Connor & Hewitt, LTD. | Victoria, TX 77901 | Oil & Gas Operator | Jun 1998 |
| 21530 | O'Connor Energy Management, LLC | Victoria, TX 77902 | Oil Operator | Feb 2026 |
| 21531 | O'Connor, Emma | Hamburg, NY 14075 | Gas Operator | Dec 2024 |
| 21532 | O'Dell, Mitchell | Cross Plains, TX 76443 | Oil & Gas Operator | Feb 2026 |
| 21533 | O'Donnell Bill C | Tulsa, OK 74135-4241 | Oil & Gas Operator | Oct 2014 |
| 21534 | O'Donnell Oil LLC | | Oil & Gas Operator | Nov 2025 |
| 21535 | O'Donohoe, Jack | Wichita Falls, TX 76301 | Oil & Gas Operator | May 2002 |
| 21536 | O'Gorman, Brendan & Wheeler, Anne | North Collins, NY 14111 | Gas Operator | Dec 2024 |
| 21537 | O'Gorman, Kevin | Eden, NY 14057 | Gas Operator | Dec 2024 |
| 21538 | O'Hare Energy Co | | Oil Operator | Dec 1983 |
| 21539 | O'Hern Morris D | Mounds, OK 74047-5163 | Oil & Gas Operator | Sep 2016 |
| 21540 | O'Leary'S Oil & Gas Inc. | Arcadia, FL 34266 | Oil & Gas Operator | May 2008 |
| 21541 | O'Malley Production Co Inc. | | Oil & Gas Operator | Mar 1988 |
| 21542 | O'Meara LLC | | Oil & Gas Operator | Oct 2022 |
| 21543 | O'Meara, Inc. | | Oil & Gas Operator | Dec 2006 |
| 21544 | O'Neal Cattle Co. | Pampa, TX 79066 | Gas Operator | Feb 2026 |
| 21545 | O'Neal Oil & Gas Co | Fort Worth, TX 76107-1479 | Oil & Gas Operator | Dec 2025 |
| 21546 | O'Neal Oil Company | Nocona, TX 76255 | Oil & Gas Operator | Feb 2026 |
| 21547 | O'Neal Operating Company | Wichita Falls, TX 76307 | Oil & Gas Operator | Dec 1999 |
| 21548 | O'Neal, Lindell | Nocona, TX 76255 | Oil & Gas Operator | Nov 2025 |
| 21549 | O'Neil Properties LTD | Midland, TX 79702 | Oil & Gas Operator | Jun 2015 |
| 21550 | O'Neil, Pat | Wichita Falls, TX 76308 | Oil & Gas Operator | Nov 2005 |
| 21551 | O'Neill Properties, LTD. | Midland, TX 79702 | Oil & Gas Operator | Feb 2026 |
| 21552 | O'Ryan Oil And Gas | Odessa, TX 79768 | Oil & Gas Operator | Feb 2026 |
| 21553 | O'Sand Production, Inc. | Tomball, TX 77377 | Oil & Gas Operator | Aug 2003 |
| 21554 | O'Sullivan & Scully, Inc. | | Oil & Gas Operator | Oct 1994 |
| 21555 | O'Sullivan Oil & Gas Co., Inc. | Houston, TX 77002 | Oil & Gas Operator | Oct 2000 |
| 21556 | O'Tool Oil & Gas, LLC | Dallas, TX 75219 | Oil & Gas Operator | Feb 2026 |
| 21557 | O-K Gas SVCS | | Gas Operator | Jun 2020 |
| 21558 | O. B. And Keith Whatley | | Oil Operator | Jul 1993 |
| 21559 | O. B. Beck | | Oil Operator | Feb 1991 |
| 21560 | O. B. Mobley | | Oil & Gas Operator | Jul 1989 |
| 21561 | O. B. Mobley, Et Al | | Oil Operator | Jul 1989 |
| 21562 | O. B. Whatley | | Oil Operator | Jul 1993 |
| 21563 | O. D. Maybrier | | Oil Operator | Dec 2011 |
| 21564 | O. F. H., Inc. | | Oil Operator | May 1990 |
| 21565 | O. G., Inc. | | Oil & Gas Operator | Nov 1992 |
| 21566 | O. H. B. Inc. | San Angelo, TX 76902 | Oil & Gas Operator | Sep 2019 |
| 21567 | O. H. M. Operating | Pampa, TX 79065 | Oil & Gas Operator | Feb 2026 |
| 21568 | O. O. Cummings | | Gas Operator | Jan 1999 |
| 21569 | O.B. Whatley Oil Company, Inc. | | Oil Operator | Feb 2013 |
| 21570 | O.B., Keith & Owen B. Whatley | | Oil Operator | Jul 1989 |
| 21571 | O.G.O. Refining | Luling, TX 78648 | Oil & Gas Operator | Jun 2013 |
| 21572 | O.G.P. Operating, Inc. | Dallas, TX 75231 | Oil & Gas Operator | Feb 2026 |
| 21573 | O.I.L. Energy, Inc. | | Oil & Gas Operator | Dec 1984 |
| 21574 | O.K. Mikeal Joint Venture | Wilmington, DE 19803 | Oil & Gas Operator | Jun 2012 |
| 21575 | O.T. Oil | Kilgore, TX 75663 | Oil Operator | Feb 2026 |
| 21576 | O7 Saltwater Disposal LLC | Marietta, OK 73448 | Oil Operator | Nov 2025 |
| 21577 | Oahe Oil Company | Texline, TX 79087 | Oil & Gas Operator | May 2004 |
| 21578 | Oak Dale Drilling Co | Logan, OH 43138-1851 | Oil & Gas Operator | Dec 2015 |
| 21579 | Oak Energy, LLC | Houston, TX 77027 | Oil & Gas Operator | Feb 2026 |
| 21580 | Oak Grove Resources, LLC | | Gas Operator | Aug 2025 |
| 21581 | Oak Hill Petroleum Corporation | Oklahoma City, OK 73116-5627 | Oil & Gas Operator | Oct 2025 |
| 21582 | Oak Hills Drilling & Oper., LLC | Holdenville, OK 74848 | Oil & Gas Operator | May 2013 |
| 21583 | Oak Hills Energy Inc | Holdenville, OK 74848-0470 | Oil & Gas Operator | Sep 2014 |
| 21584 | Oak Prairie Operations, LLC | The Woodlands, TX 77381 | Oil & Gas Operator | Feb 2026 |
| 21585 | Oak Resources Inc | Tulsa, OK 74153 | Oil & Gas Operator | Aug 2013 |
| 21586 | Oak Ridge LLC | Wellsville, KS 66092 | Oil Operator | Dec 2019 |
| 21587 | Oak Tree Natural Res LLC | Oklahoma City, OK 73120-5065 | Oil & Gas Operator | Mar 2015 |
| 21588 | Oak Valley Operating, LLC | The Woodlands, TX 77380 | Oil & Gas Operator | Jun 2015 |
| 21589 | Oak Valley SWD LLC | Enid, OK 73703-4637 | Oil Operator | Aug 2022 |
| 21590 | Oakes Gas Co Inc | Kane, PA 16735-3905 | Gas Operator | Dec 2023 |
| 21591 | Oakfield Energy LLC | | Oil Operator | Jun 2019 |
| 21592 | Oakland Corporation | | Oil & Gas Operator | Dec 1981 |
| 21593 | Oakland Petroleum Oper Co., Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Feb 2026 |
| 21594 | Oakley Oil & Gas, L.L.C. | | Oil & Gas Operator | Mar 2012 |
| 21595 | Oakmont CC | Oakmont, PA 15139-1135 | Gas Operator | Dec 2024 |
| 21596 | Oakmont Oil And Gas | Graham, TX 76450 | Oil & Gas Operator | Feb 2026 |
| 21597 | Oakridge Energy, Inc. | Wichita Falls, TX 76302 | Oil & Gas Operator | Feb 2026 |
| 21598 | Oakridge Oil And Gas, LP | Jacksboro, TX 76458 | Oil & Gas Operator | Feb 2026 |
| 21599 | Oaks Petroleum I | | Oil Operator | Jul 1987 |
| 21600 | Oaktree Oil Company | Albany, TX 76430 | Oil & Gas Operator | Feb 2026 |