| 20601 | Odyssey Operating Company | Shreveport, LA 71106 | Oil & Gas Operator | Sep 2020 |
| 20602 | Odyssey Petroleum Company | Houston, TX 77010 | Oil & Gas Operator | Apr 1995 |
| 20603 | Odyssey Petroleum Corp. | | Oil & Gas Operator | Jun 2011 |
| 20604 | Oedekoven Amerifields Resources LLC | Sugar Land, TX 77478 | Oil Operator | Apr 2026 |
| 20605 | Oedekoven Water & Hot Oil | Recluse, WY 82725 | Oil & Gas Operator | Jun 2026 |
| 20606 | Oeth DRLG Co | | Oil Operator | Dec 2018 |
| 20607 | Oex-1 LLC | Tulsa, OK 74105-5153 | Oil & Gas Operator | Mar 2024 |
| 20608 | Oexco, Inc. | Tulsa, OK 74136 | Oil & Gas Operator | Mar 2015 |
| 20609 | Off Broadway Mineral Rights LLC | | Oil & Gas Operator | Oct 2024 |
| 20610 | Offield Lease Operations LLC | Wilson, OK 73463 | Oil & Gas Operator | May 2026 |
| 20611 | Offset Oil & Gas | Big Spring, TX 79720 | Oil & Gas Operator | Aug 2003 |
| 20612 | Offshore Group, Inc. The | Houston, TX 77024 | Oil & Gas Operator | Jul 2026 |
| 20613 | Offshore Oil & Gas Inc | Houston, TX 77063 | Oil & Gas Operator | Sep 1994 |
| 20614 | Offshore Shelf LLC | | Oil & Gas Operator | Dec 2007 |
| 20615 | Ofs-Tulsa Corporation | Fort Worth, TX 76102 | Oil & Gas Operator | Feb 1997 |
| 20616 | Oft Inc. | Houston, TX 77079 | Oil & Gas Operator | Jul 2026 |
| 20617 | Og Co., Inc. | Houston, TX 77057 | Oil & Gas Operator | Jul 2026 |
| 20618 | Oga Operating L.L.C. | Midland, TX 79702 | Oil & Gas Operator | Jan 2000 |
| 20619 | Ogden Oil Co., Inc. | | Oil Operator | May 1981 |
| 20620 | Ogden Resources Corporation | Bryan, TX 77805 | Oil & Gas Operator | Jul 2026 |
| 20621 | Ogden Resources, LTD. | Bryan, TX 77802 | Oil & Gas Operator | Feb 2009 |
| 20622 | Ogh Oil Company | | Oil Operator | Sep 1995 |
| 20623 | Ogle Petroleum Inc. | | Oil & Gas Operator | Dec 1989 |
| 20624 | Oglesby Oil Company | | Oil & Gas Operator | Nov 2023 |
| 20625 | Oglesby Prod & Expl Co Inc | | Oil & Gas Operator | Nov 1987 |
| 20626 | Oglesby, Marshall | | Oil Operator | May 1990 |
| 20627 | Ogog Operating, LLC | Dallas, TX 75367 | Oil & Gas Operator | Jul 2026 |
| 20628 | Ogris Operating, LLC | Midland, TX 79710 | Oil & Gas Operator | Jul 2026 |
| 20629 | Ogs Operating Company, Inc. | Midland, TX 79701 | Oil & Gas Operator | Sep 2008 |
| 20630 | Ogx Operating, LLC | Midland, TX 79702 | Oil & Gas Operator | Jul 2026 |
| 20631 | Ogx Resources LLC | Midland, TX 79702 | Oil & Gas Operator | Oct 2011 |
| 20632 | Ohio Energy Assets, Inc. | Laurelville, OH 43135 | Oil & Gas Operator | Dec 2014 |
| 20633 | Ohio Energy Group Inc | Uniontown, OH 44685 | Oil & Gas Operator | Dec 1988 |
| 20634 | Ohio Energy Operators LLC | Colorado Spring, CO 80908 | Oil Operator | Dec 2018 |
| 20635 | Ohio Kentucky Oil Corporation | Lexington, KY 40503 | Oil & Gas Operator | Dec 2024 |
| 20636 | Ohio L & M Company Inc | Marietta, OH 45750 | Oil & Gas Operator | Dec 2008 |
| 20637 | Ohio Natural Fuel Co | Canton, OH 44718 | Oil & Gas Operator | Dec 1985 |
| 20638 | Ohio Oil & Gas | Fowler, OH 44418 | Oil & Gas Operator | Dec 1988 |
| 20639 | Ohio Production Corp | Westerville, OH 43081 | Oil & Gas Operator | Dec 2001 |
| 20640 | Ohio Production* | Newark, OH 43055 | Oil & Gas Operator | Dec 1987 |
| 20641 | Ohio Valley Energy Systems Corp | Austintown, OH 44515 | Oil & Gas Operator | Dec 2025 |
| 20642 | Ohio Valley Energy, Inc | Livermore, KY 42352 | Oil Operator | Dec 2023 |
| 20643 | Ohlhausen Oil Company | Abilene, TX 79608 | Oil & Gas Operator | Jul 2026 |
| 20644 | Oi Auburn, Inc. | Tulsa, OK 74135 | Gas Operator | Dec 2025 |
| 20645 | Oil & Gas Acquisition Group Inc | Austin, TX 78716 | Oil & Gas Operator | May 2003 |
| 20646 | Oil & Gas Development Company | | Oil & Gas Operator | May 1991 |
| 20647 | Oil & Gas Exploration Inc | Cleveland, OK 74020 | Oil & Gas Operator | Aug 2013 |
| 20648 | Oil & Gas MGMT Inc | Mount Pleasant, PA 15666-3304 | Oil & Gas Operator | Dec 2024 |
| 20649 | Oil & Gas Operations | Midland, TX 79706 | Oil & Gas Operator | Jul 2026 |
| 20650 | Oil & Gas Producers, Inc | Topeka, KS 66604 | Oil Operator | Jun 2004 |
| 20651 | Oil & Gas Properties | Midland, TX 79704 | Oil & Gas Operator | Jul 2026 |
| 20652 | Oil & Gas Property MGMT., Inc. | Dallas, TX 75201 | Oil & Gas Operator | Jul 1996 |
| 20653 | Oil & Gas Servic | | Oil Operator | Jun 1983 |
| 20654 | Oil & Gas Solutions LTD | Wooster, OH 44691 | Oil & Gas Operator | Dec 2007 |
| 20655 | Oil & Gas SVC Inc | Reelsville, IN 46171-9686 | Gas Operator | Dec 1991 |
| 20656 | Oil & Realty Devlop Inc | Columbus, OH 43212 | Oil Operator | Dec 1986 |
| 20657 | Oil And Gas Futures, Inc. | | Oil & Gas Operator | May 1977 |
| 20658 | Oil And Gas Management, Inc. | Kansas City, MO 64106 | Oil Operator | Apr 2011 |
| 20659 | Oil Capital Corporation | Littleton, CO 80122 | Gas Operator | May 2009 |
| 20660 | Oil Capital Operating, LLC | Tulsa, OK 74103 | Oil & Gas Operator | Jul 2026 |
| 20661 | Oil Center Operating Inc | Fort Worth, TX 76102-5108 | Oil & Gas Operator | Apr 2014 |
| 20662 | Oil Coast Corp. | S Houston, TX 77587 | Oil & Gas Operator | Jul 2026 |
| 20663 | Oil Company Of America, Inc. | Hays, KS 67601 | Oil Operator | Dec 2009 |
| 20664 | Oil Country Management, Inc. | | Oil & Gas Operator | Jan 2005 |
| 20665 | Oil Creek Operators LLC | Franklin, PA 16323 | Oil Operator | Dec 2025 |
| 20666 | Oil Creek Production Company | Prague, OK 74864-0667 | Oil & Gas Operator | Mar 2026 |
| 20667 | Oil Development Co | | Oil & Gas Operator | Jan 1979 |
| 20668 | Oil Drillers & D | | Oil & Gas Operator | Feb 1992 |
| 20669 | Oil Enterprises | Logan, OH 43138 | Oil & Gas Operator | Dec 2025 |
| 20670 | Oil Exploration Of America Inc | Sisseton, SD 57262-9503 | Oil & Gas Operator | Jun 2001 |
| 20671 | Oil Field Manage | | Oil Operator | Jun 1991 |
| 20672 | Oil Inc | | Oil & Gas Operator | Dec 1971 |
| 20673 | Oil Internationa | | Oil Operator | Jun 1986 |
| 20674 | Oil Investors Inc | Crescent, OK 73028 | Oil & Gas Operator | May 2026 |
| 20675 | Oil Lease Operating Co. | Coldspring, TX 77331 | Oil & Gas Operator | Aug 2003 |
| 20676 | Oil Lift Inc | Metairie, LA 70002 | Oil & Gas Operator | Apr 2020 |
| 20677 | Oil Management Corporation | Dallas, TX 75206 | Oil & Gas Operator | Apr 2022 |
| 20678 | Oil Mountain Energy Inc | Casper, WY 82609 | Oil Operator | Jun 2026 |
| 20679 | Oil Operations Inc | | Oil & Gas Operator | Apr 2011 |
| 20680 | Oil Operators Inc. | | Oil & Gas Operator | Nov 2024 |
| 20681 | Oil Palace, Inc. | | Oil Operator | Jun 2016 |
| 20682 | Oil Partners | Salina, KS 67401 | Oil Operator | Jun 2001 |
| 20683 | Oil Partners, LLC | Salina, KS 67401 | Oil Operator | Mar 2026 |
| 20684 | Oil Patch Energy LLC | Broken Arrow, OK 74014 | Oil & Gas Operator | Nov 2025 |
| 20685 | Oil Patch Operators Co., L.L.C. | Kilgore, TX 75663 | Oil & Gas Operator | Jul 2026 |
| 20686 | Oil Patch Operators, LLC | | Oil & Gas Operator | Jul 2005 |
| 20687 | Oil Pool Inc | Tulsa, OK 74132-2659 | Oil & Gas Operator | May 2026 |
| 20688 | Oil Producers In | | Oil & Gas Operator | Dec 1996 |
| 20689 | Oil Producers, Inc. Of Kansas | Wichita, KS 67206 | Oil & Gas Operator | Jul 2026 |
| 20690 | Oil Production Management Inc | Squaw Valley, CA 93675-9725 | Oil & Gas Operator | Dec 2002 |
| 20691 | Oil Production S | | Oil Operator | Sep 1993 |
| 20692 | Oil Production Systems Inc | Cushing, OK 74023 | Oil & Gas Operator | Jan 2013 |
| 20693 | Oil Projects, LLC | Houston, TX 77027 | Oil & Gas Operator | Jul 2026 |
| 20694 | Oil Prop Company | | Oil & Gas Operator | Sep 1995 |
| 20695 | Oil Prop Investm | | Oil Operator | Dec 1995 |
| 20696 | Oil Properties Co., Inc. | Wichita, KS 67208 | Gas Operator | Dec 2009 |
| 20697 | Oil Property Man | | Oil & Gas Operator | Jun 1995 |
| 20698 | Oil Property Management Inc | Attica, KS 67009 | Oil & Gas Operator | Feb 2021 |
| 20699 | Oil Recovery Systems Inc | Tulsa, OK 74145-4619 | Oil & Gas Operator | Apr 2026 |
| 20700 | Oil Recovery, Inc. | | Oil Operator | Sep 1992 |