| 21601 | Omni Petroleum Corporation | Austin, TX 78738 | Oil & Gas Operator | Apr 2025 |
| 21602 | Omr Drilling & Acquisition LLC | Albany, KY 42602 | Oil Operator | Dec 2015 |
| 21603 | On Pointe Operating LLC | Jones, OK 73049 | Oil & Gas Operator | Apr 2025 |
| 21604 | On-Line Oil Inc | Oklahoma City, OK 73105-5208 | Oil & Gas Operator | Mar 2015 |
| 21605 | Onapa Gas Company LLC | Tulsa, OK 74136-7253 | Gas Operator | Nov 2019 |
| 21606 | Onaroll Operating LLC | Levelland, TX 79336 | Oil Operator | Apr 2025 |
| 21607 | Onco Petroleum USA Inc | | Oil Operator | Dec 2009 |
| 21608 | One Epoch Energy, Inc. | Abilene, TX 79604 | Oil & Gas Operator | Mar 2008 |
| 21609 | One Nickel Operating LLC | Westbrook, TX 79565 | Oil Operator | Apr 2025 |
| 21610 | One Source Financial Services Inc. | McAllen, TX 78501 | Gas Operator | Dec 2019 |
| 21611 | One Tec Operating, LLC | Houston, TX 77002 | Oil & Gas Operator | Nov 2007 |
| 21612 | One World Operating, LLC | Tampa, FL 33602 | Oil & Gas Operator | Apr 2025 |
| 21613 | Oneenergy Partners Operating, LLC | Houston, TX 77019 | Oil & Gas Operator | Nov 2018 |
| 21614 | Oneida Energy Corporation | Tulsa, OK 74137 | Oil & Gas Operator | Jul 2003 |
| 21615 | Oneok Bushton Proces | | Gas Operator | Mar 2007 |
| 21616 | Oneok Energy Service | | Gas Operator | Dec 2008 |
| 21617 | Oneok Exploratio | | Oil & Gas Operator | Mar 1995 |
| 21618 | Oneok Exploration Company | Tulsa, OK 74102 | Oil & Gas Operator | Feb 2017 |
| 21619 | Oneok Field Services Company | Tulsa, OK 74103 | Oil & Gas Operator | Jul 2022 |
| 21620 | Oneok Gas Processing LLC | Tulsa, OK 74103 | Oil & Gas Operator | May 2018 |
| 21621 | Oneok Gas Transportation Co | Tulsa, OK 74121-2089 | Oil & Gas Operator | Oct 2014 |
| 21622 | Oneok Resources Company | Tulsa, OK 74102 | Oil & Gas Operator | Feb 2017 |
| 21623 | Onexxx Prod & Exploration Corp | Jeannette, PA 15644-9691 | Gas Operator | Dec 2024 |
| 21624 | Onnen, Gerhard E. | Yates Center, KS 66783 | Oil Operator | Feb 2002 |
| 21625 | Onpoint Oil & Gas LLC | Oklahoma City, OK 73170-4848 | Oil & Gas Operator | Jan 2025 |
| 21626 | Onshore Exp Cor-La Nat Res Inc | | Oil & Gas Operator | Oct 1978 |
| 21627 | Onshore Pipeline Const Co Inc | | Oil & Gas Operator | Aug 1998 |
| 21628 | Onshore Royalties LLC | Houston, TX 77269 | Oil & Gas Operator | Feb 2025 |
| 21629 | Onshore, L.L.C. | Wichita, KS 67205 | Oil & Gas Operator | Dec 2009 |
| 21630 | Onyx Energy Corporation | Oklahoma City, OK 73157 | Oil & Gas Operator | May 1994 |
| 21631 | Onyx Energy Dev Of Texas Inc. | | Oil Operator | Dec 1996 |
| 21632 | Onyx Energy Of Texas Inc. | | Oil Operator | Dec 1996 |
| 21633 | Onyx Industries LTD, Inc. | Wichita Falls, TX 76308 | Oil & Gas Operator | Aug 2003 |
| 21634 | Onyx Int'L Exploration LLC | | Oil & Gas Operator | Dec 2015 |
| 21635 | Onyx Producing Company, Inc. | Pampa, TX 79066 | Oil & Gas Operator | Mar 2008 |
| 21636 | Onyx Properties Corp | Oklahoma City, OK 73114 | Oil & Gas Operator | May 2006 |
| 21637 | Onyxx Energy LLC | | Oil & Gas Operator | Mar 2017 |
| 21638 | Onyxx Oil Corpor | | Oil Operator | Jul 1992 |
| 21639 | Oolite Energy Corp | Amarillo, TX 79105 | Oil & Gas Operator | Apr 2022 |
| 21640 | Oonk, Harvey D. | Clymer, NY 14724 | Gas Operator | Dec 2023 |
| 21641 | Opal Energy, Inc. | Katy, TX 77494 | Oil & Gas Operator | Jun 2009 |
| 21642 | Opal Oil Inc. | | Oil Operator | Sep 2021 |
| 21643 | Opal Operating Company LLC | Oklahoma City, OK 73142 | Oil & Gas Operator | Apr 2025 |
| 21644 | Opal Resources Operating Co.,LLC | Cypress, TX 77429 | Oil & Gas Operator | Jan 2019 |
| 21645 | Opco LLC | Chase, KS 67524 | Oil Operator | Dec 2019 |
| 21646 | Opco Oil & Gas Co. | Dallas, TX 75231 | Oil & Gas Operator | Aug 2003 |
| 21647 | Opdycke Lease Partners, A General Partnership | Russell, KS 67665 | Oil Operator | Dec 2024 |
| 21648 | Opef Partnership, A General Partnership | Overland Park, KS 66221 | Oil Operator | Dec 2011 |
| 21649 | Open Door Holdings Inc | Surprise, AZ 85387-2015 | Oil & Gas Operator | Feb 2024 |
| 21650 | Open Door Productions Inc | Muskogee, OK 74401-1032 | Oil & Gas Operator | Apr 2020 |
| 21651 | Open Flow Gas Supply Corp | Du Bois, PA 15801-2442 | Oil & Gas Operator | Dec 2024 |
| 21652 | Open Range Energy LLC | Jones, OK 73049-8744 | Oil & Gas Operator | Nov 2024 |
| 21653 | Operating Engineers Local 17 Training Fund | Lake VIew, NY 14085 | Gas Operator | Dec 2023 |
| 21654 | Operator Unknown | Charleston, WV 25304-0000 | Oil & Gas Operator | Dec 2021 |
| 21655 | Opes Production Inc | Buffalo, WY 82834 | Gas Operator | Mar 2015 |
| 21656 | Opex Energy, LLC | Houston, TX 77042 | Oil & Gas Operator | Mar 2008 |
| 21657 | Opmi Operating Company | Houston, TX 77057 | Oil & Gas Operator | Jun 2008 |
| 21658 | Ops Group Limited | Houston, TX 77060 | Oil & Gas Operator | Jun 2014 |
| 21659 | Optima Conservation Resources Exploration LLC | | Oil & Gas Operator | Dec 2024 |
| 21660 | Optima Exploration LLC | Tulsa, OK 74116-5664 | Oil & Gas Operator | Mar 2015 |
| 21661 | Optimistic Oil Co. | | Oil & Gas Operator | Dec 1991 |
| 21662 | Optimum Exploration LLC | Dallas, TX 75240 | Oil & Gas Operator | Apr 2025 |
| 21663 | Opubco Resources Of TX Inc | Dallas, TX 75231 | Oil & Gas Operator | Sep 2005 |
| 21664 | Ora Oil Company | | Oil & Gas Operator | May 2017 |
| 21665 | Oracle Oil, LLC | | Oil & Gas Operator | Jul 2013 |
| 21666 | Oracle Resources Oklahoma LP | Dallas, TX 75240-5751 | Oil & Gas Operator | Feb 2008 |
| 21667 | Orange Petroleum Co. | Orangefield, TX 77639 | Oil & Gas Operator | May 1995 |
| 21668 | Orangefield Operating Corporation | Dallas, TX 75382 | Oil Operator | Apr 2025 |
| 21669 | Orason Resources Inc | Tulsa, OK 74169-1225 | Oil & Gas Operator | Nov 2006 |
| 21670 | Orb Exploration, L.L.C. | | Oil & Gas Operator | Jun 2017 |
| 21671 | Orbis Energy, L.L.C. | Austin, TX 78746 | Oil & Gas Operator | Oct 2001 |
| 21672 | Orbit Crude, Inc. | Midland, TX 79710 | Oil & Gas Operator | Apr 2025 |
| 21673 | Orbit Enterprises, Inc. | Lovington, NM 88260 | Oil & Gas Operator | Mar 2015 |
| 21674 | Orbit Gas Transmission, Inc | Owensboro, KY 42303 | Oil & Gas Operator | Dec 2023 |
| 21675 | Orbit Petroleum, Inc. | Irving, TX 75038 | Oil & Gas Operator | Sep 2010 |
| 21676 | Orbitron Operating Corp. | Fort Worth, TX 76102 | Oil & Gas Operator | Dec 1995 |
| 21677 | Orbrie Luman | Odessa, TX 79761 | Oil & Gas Operator | Feb 2025 |
| 21678 | Orca Operating Company LLC | Houston, TX 77056 | Oil & Gas Operator | Feb 2025 |
| 21679 | Oren Stone | Erick, OK 73645-4542 | Gas Operator | Jun 2022 |
| 21680 | Organic Energy Company LLC | | Oil & Gas Operator | Mar 2025 |
| 21681 | Origin Prod Co Gonzales Prop LLC | New Braunfels, TX 78132 | Oil & Gas Operator | Apr 2025 |
| 21682 | Origin Production Company, Inc. | New Braunfels, TX 78132 | Oil & Gas Operator | Apr 2025 |
| 21683 | Origin Production Group LLC | Luling, TX 78648 | Oil Operator | Apr 2025 |
| 21684 | Oringderff, Alma Oil Properties | Dallas, TX 75225 | Oil & Gas Operator | Mar 2012 |
| 21685 | Oriole Operating LLC | Wichita Falls, TX 76308 | Oil Operator | Apr 2025 |
| 21686 | Orion Energen Inc. | Austin, TX 78731 | Oil & Gas Operator | Jul 2023 |
| 21687 | Orion Energy Corp | MT Vernon, IL 62864 | Oil & Gas Operator | Dec 1984 |
| 21688 | Orion Energy Partners LP | Denver, CO 80202 | Oil & Gas Operator | Oct 2024 |
| 21689 | Orion Exploration LLC | Tulsa, OK 74105-5153 | Oil & Gas Operator | Apr 2015 |
| 21690 | Orion Exploration Partners LLC | Tulsa, OK 74105-5153 | Oil & Gas Operator | Jan 2025 |
| 21691 | Orion Oil & Gas Prop | Roswell, NM 88202 | Oil & Gas Operator | Apr 1998 |
| 21692 | Orion Oil & Gas Properties | Amarillo, TX 79109 | Gas Operator | Oct 2000 |
| 21693 | Orion Oil & Gas, LLC | Houston, TX 77042 | Oil & Gas Operator | Oct 2007 |
| 21694 | Orion Oil And Gas Corporation | Houston, TX 77082 | Oil & Gas Operator | Apr 2025 |
| 21695 | Orion Petro Corp | MT Vernon, IL 62864 | Oil & Gas Operator | Dec 2016 |
| 21696 | Orisol Oil Co. | Houston, TX 77206 | Oil Operator | Jun 2000 |
| 21697 | Orla Petco Inc & Hopi Drilling Co | Midland, TX 79702 | Oil Operator | Sep 2004 |
| 21698 | Orla Petco, Inc. | Midland, TX 79702 | Oil & Gas Operator | Apr 2025 |
| 21699 | Orland Oil & Gas LLC | FT Lauderdale, FL 33305 | Oil Operator | Apr 2025 |
| 21700 | Orleans Exploration Co., Inc. | | Oil & Gas Operator | Aug 1990 |