| 20601 | O'Leary'S Oil & Gas Inc. | Arcadia, FL 34266 | Oil & Gas Operator | May 2008 |
| 20602 | O'Malley Production Co. Inc. | | Oil & Gas Operator | Mar 1988 |
| 20603 | O'Meara LLC | | Oil & Gas Operator | Oct 2022 |
| 20604 | O'Meara, Inc. | | Oil & Gas Operator | Dec 2006 |
| 20605 | O'Neal Cattle Co. | Pampa, TX 79066 | Gas Operator | Nov 2024 |
| 20606 | O'Neal Oil & Gas Co | Fort Worth, TX 76107-1479 | Oil & Gas Operator | Sep 2024 |
| 20607 | O'Neal Oil Company | Nocona, TX 76255 | Oil & Gas Operator | Nov 2024 |
| 20608 | O'Neal Operating Company | Wichita Falls, TX 76307 | Oil & Gas Operator | Dec 1999 |
| 20609 | O'Neal, Lindell | Nocona, TX 76255 | Oil & Gas Operator | Aug 2024 |
| 20610 | O'Neil Properties LTD | Midland, TX 79702 | Oil & Gas Operator | Jun 2015 |
| 20611 | O'Neil, Pat | Wichita Falls, TX 76308 | Oil & Gas Operator | Nov 2005 |
| 20612 | O'Neill Properties, LTD. | Midland, TX 79702 | Oil & Gas Operator | Nov 2024 |
| 20613 | O'Ryan Oil And Gas | Odessa, TX 79768 | Oil & Gas Operator | Nov 2024 |
| 20614 | O'Sand Production, Inc. | Tomball, TX 77377 | Oil & Gas Operator | Aug 2003 |
| 20615 | O'Sullivan & Scully, Inc. | | Oil & Gas Operator | Oct 1994 |
| 20616 | O'Sullivan Oil & Gas Co., Inc. | Houston, TX 77002 | Oil & Gas Operator | Oct 2000 |
| 20617 | O'Tool Oil & Gas, LLC | Dallas, TX 75219 | Oil & Gas Operator | Nov 2024 |
| 20618 | O. B. And Keith Whatley | | Oil Operator | Jul 1993 |
| 20619 | O. B. Beck | | Oil Operator | Feb 1991 |
| 20620 | O. B. Mobley | | Oil & Gas Operator | Jul 1989 |
| 20621 | O. B. Mobley, Et Al | | Oil Operator | Jul 1989 |
| 20622 | O. B. Whatley | | Oil Operator | Jul 1993 |
| 20623 | O. D. Maybrier | | Oil Operator | Dec 2011 |
| 20624 | O. F. H., Inc. | | Oil Operator | May 1990 |
| 20625 | O. G., Inc. | | Oil & Gas Operator | Nov 1992 |
| 20626 | O. H. B. Inc. | San Angelo, TX 76902 | Oil & Gas Operator | Sep 2019 |
| 20627 | O. H. M. Operating | Pampa, TX 79065 | Oil & Gas Operator | Nov 2024 |
| 20628 | O. O. Cummings | | Gas Operator | Jan 1999 |
| 20629 | O.B. Whatley Oil Company, Inc. | | Oil Operator | Feb 2013 |
| 20630 | O.B., Keith & Owen B. Whatley | | Oil Operator | Jul 1989 |
| 20631 | O.G.O. Refining | Luling, TX 78648 | Oil & Gas Operator | Jun 2013 |
| 20632 | O.G.P. Operating, Inc. | Dallas, TX 75231 | Oil & Gas Operator | Nov 2024 |
| 20633 | O.I.L. Energy, Inc. | | Oil & Gas Operator | Dec 1984 |
| 20634 | O.T. Oil | Kilgore, TX 75663 | Oil Operator | Nov 2024 |
| 20635 | Oahe Oil Company | Texline, TX 79087 | Oil & Gas Operator | May 2004 |
| 20636 | Oak Dale Drilling Co | Logan, OH 43138-1851-1851 | Oil & Gas Operator | Dec 2015 |
| 20637 | Oak Energy, LLC | Houston, TX 77027 | Oil & Gas Operator | Nov 2024 |
| 20638 | Oak Grove Resources, LLC | | Gas Operator | Jun 2024 |
| 20639 | Oak Hill Petroleum Corporation | Oklahoma City, OK 73116-5627 | Oil & Gas Operator | Jul 2024 |
| 20640 | Oak Hills Drilling & Oper., LLC | Holdenville, OK 74848 | Oil & Gas Operator | May 2013 |
| 20641 | Oak Hills Energy Inc | Holdenville, OK 74848-0470 | Oil & Gas Operator | Sep 2014 |
| 20642 | Oak Prairie Operations, LLC | The Woodlands, TX 77381 | Oil & Gas Operator | Nov 2024 |
| 20643 | Oak Resources Inc | Tulsa, OK 74153 | Oil & Gas Operator | Aug 2013 |
| 20644 | Oak Ridge LLC | Wellsville, KS 66092 | Oil Operator | Dec 2019 |
| 20645 | Oak Tree Natural Res LLC | Oklahoma City, OK 73120-5065 | Oil & Gas Operator | Mar 2015 |
| 20646 | Oak Valley Operating, LLC | The Woodlands, TX 77380 | Oil & Gas Operator | Jun 2015 |
| 20647 | Oak Valley SWD LLC | Enid, OK 73703-4637 | Oil Operator | Aug 2022 |
| 20648 | Oakes Gas Co Inc | Kane, PA 16735-3905 | Gas Operator | Dec 2023 |
| 20649 | Oakfield Energy LLC | | Oil Operator | Jun 2019 |
| 20650 | Oakland Corporation | | Oil & Gas Operator | Dec 1981 |
| 20651 | Oakland Petroleum Oper Co., Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Nov 2024 |
| 20652 | Oakley Oil & Gas, L.L.C. | | Oil & Gas Operator | Mar 2012 |
| 20653 | Oakmont CC | Oakmont, PA 15139-1135 | Gas Operator | Dec 2023 |
| 20654 | Oakmont Oil And Gas | Graham, TX 76450 | Oil Operator | Nov 2024 |
| 20655 | Oakridge Energy, Inc. | Wichita Falls, TX 76302 | Oil & Gas Operator | Nov 2024 |
| 20656 | Oakridge Oil And Gas, LP | Jacksboro, TX 76458 | Oil & Gas Operator | Nov 2024 |
| 20657 | Oaks Petroleum I | | Oil Operator | Jul 1987 |
| 20658 | Oaktree Oil Company | Albany, TX 76430 | Oil & Gas Operator | Nov 2024 |
| 20659 | Oakwood Resources, Inc. | Dallas, TX 75374 | Oil & Gas Operator | May 1998 |
| 20660 | Oasis Energy Resources LLC | Norman, OK 73072-9668 | Oil & Gas Operator | Aug 2024 |
| 20661 | Oasis Operating, Inc. | Lubbock, TX 79404 | Oil & Gas Operator | Nov 2020 |
| 20662 | Oasis Petroleum North America LLC | Houston, TX 77002 | Oil & Gas Operator | Oct 2024 |
| 20663 | Oasis Petroleum Permian LLC | Houston, TX 77002 | Oil & Gas Operator | Nov 2024 |
| 20664 | Oasis Production Co., Inc. | | Oil & Gas Operator | Jun 1988 |
| 20665 | Oast, Thomas H. | Greenville, NC 27835 | Oil Operator | Nov 1985 |
| 20666 | Oates, John Co., Inc. | Stinnett, TX 79083 | Oil & Gas Operator | Nov 2024 |
| 20667 | Obax Oil And Gas LLC | Saint Louis, MO 63131 | Oil Operator | Nov 2024 |
| 20668 | Obele Oil Corporation | Sedona, AZ 86336-5745 | Oil & Gas Operator | May 2017 |
| 20669 | Obele Operating Company LLC | Sedona, AZ 86336-5745 | Oil & Gas Operator | Aug 2024 |
| 20670 | Oberlander Leslie A Jake | Covington, OK 73730 | Oil Operator | Jun 2007 |
| 20671 | Obermeyer, C R | | Oil Operator | Dec 2022 |
| 20672 | Obermiller Clarence Trust | Creston, OH 44217 | Oil & Gas Operator | Dec 1987 |
| 20673 | Obermiller Paul J | Creston, OH 44217 | Oil & Gas Operator | Dec 2014 |
| 20674 | Oblaen Resources LLC | Wallis, TX 77485 | Oil & Gas Operator | Nov 2024 |
| 20675 | Obsidian Energy, LLC | McKinney, TX 75071 | Oil & Gas Operator | Jun 2024 |
| 20676 | Occ Operating Co. | | Oil & Gas Operator | Apr 2019 |
| 20677 | Occidental Energy Company, Inc. | Houston, TX 77282 | Oil & Gas Operator | Jul 2021 |
| 20678 | Occidental Energy Marketing, Inc. | Houston, TX 77227 | Gas Operator | Sep 2015 |
| 20679 | Occidental Energy MKT Inc | Houston, TX 77001 | Oil & Gas Operator | Jan 2011 |
| 20680 | Occidental Of Elk Hills Inc. | | Oil & Gas Operator | Dec 2014 |
| 20681 | Occidental Permian LTD. | Houston, TX 77046 | Oil & Gas Operator | Nov 2024 |
| 20682 | Occidental Petroleum Corporation | | Oil & Gas Operator | Dec 2021 |
| 20683 | Occidental W TX Overthrust, Inc. | Houston, TX 77210 | Oil & Gas Operator | Dec 2021 |
| 20684 | Ocean Energy Inc | Houston, TX 77002 | Oil & Gas Operator | Aug 2003 |
| 20685 | Ocean Energy Inc Ndba Devon Louisiana Corp | | Oil & Gas Operator | Jul 2001 |
| 20686 | Ocean Energy Resources Inc. | Houston, TX 77002 | Oil & Gas Operator | Jul 2024 |
| 20687 | Ocfiw Oil Company, Inc. | Hartington, NE 68739 | Oil & Gas Operator | Dec 2009 |
| 20688 | Ochiltree Oil Company | Edmond, OK 73034 | Oil & Gas Operator | Apr 2020 |
| 20689 | Oci LLC | Thermopolis, WY 82443 | Oil Operator | Jan 2024 |
| 20690 | Octagon Resources Corporation | | Oil Operator | Mar 2005 |
| 20691 | Octagon Resources LLC | Norman, OK 73071-1295 | Oil & Gas Operator | May 2015 |
| 20692 | Octane Energy Operating, LLC | Midland, TX 79701 | Oil & Gas Operator | Nov 2024 |
| 20693 | Odebralski, Michael & Connie | Fredonia, NY 14063 | Gas Operator | Dec 2023 |
| 20694 | Odegard Energy, Inc. | Houston, TX 77024 | Oil & Gas Operator | Jul 2020 |
| 20695 | Odegard Resources/Omni Exp | Columbus, OH 43207 | Oil & Gas Operator | Sep 1986 |
| 20696 | Odell Larry | Oologah, OK 74053 | Oil Operator | Apr 2011 |
| 20697 | Oden, Robin H., Inc. | Midland, TX 79702 | Oil & Gas Operator | Apr 1994 |
| 20698 | Odessa Exploration, Inc. | Midland, TX 79702 | Oil & Gas Operator | Nov 2024 |
| 20699 | Odessa Oil Investment Co., Inc. | Odessa, TX 79762 | Oil & Gas Operator | Nov 2016 |
| 20700 | Odom, Claude | | Oil Operator | Jul 1983 |