| 20801 | Olympus Prop Inc | | Oil & Gas Operator | Dec 1997 |
| 20802 | Omac Oil & Gas Co | Newark, OH 43055 | Oil & Gas Operator | Dec 1990 |
| 20803 | Omar Operating Company | Midland, TX 79702 | Oil & Gas Operator | Sep 2013 |
| 20804 | Omber Petroleum & Energy Corp. | New Braunfels, TX 78131 | Oil & Gas Operator | Sep 2026 |
| 20805 | Omeara Bros. | | Oil & Gas Operator | Oct 1982 |
| 20806 | Omega Alpha Resources, LLC | Dallas, TX 75219 | Oil Operator | Sep 2026 |
| 20807 | Omega Energy Corp. | Graham, TX 76450 | Oil & Gas Operator | Sep 2026 |
| 20808 | Omega Energy Incorporated | | Oil & Gas Operator | May 1998 |
| 20809 | Omega Energy, LLC | Corpus Christ, TX 78418 | Oil & Gas Operator | Sep 2026 |
| 20810 | Omega Enterprise | | Oil Operator | Sep 1990 |
| 20811 | Omega Oil Corp | Lafayette, IN 47903 | Oil & Gas Operator | Dec 1987 |
| 20812 | Omega Operating, Inc. | Odessa, TX 79769 | Oil & Gas Operator | Mar 2001 |
| 20813 | Omega Resources Inc | | Oil & Gas Operator | Nov 1998 |
| 20814 | Omimex Canada, LTD. | Fort Worth, TX 76120-3608 | Oil & Gas Operator | May 2026 |
| 20815 | Omimex Energy, Inc. | Fort Worth, TX 76120 | Oil & Gas Operator | Apr 2026 |
| 20816 | Omimex International Corp | Fort Worth, TX 76103-2300 | Oil & Gas Operator | Jun 2026 |
| 20817 | Omimex Petroleum Inc | Fort Worth, TX 76120 | Oil & Gas Operator | Aug 2022 |
| 20818 | Omimex Petroleum Inc (Co) | Newcastle, WY 82701 | Oil & Gas Operator | May 2001 |
| 20819 | Omimex Petroleum Inc (De) | Fort Worth, TX 76120 | Oil & Gas Operator | Aug 2020 |
| 20820 | Omni E & P, Inc. | San Antonio, TX 78229 | Oil Operator | Apr 2010 |
| 20821 | Omni Oil & Gas, Inc. | San Antonio, TX 78229 | Oil & Gas Operator | Oct 2017 |
| 20822 | Omni Operating Company | Osage, WY 82723 | Oil & Gas Operator | Sep 2001 |
| 20823 | Omni Operating Company(A) | Dallas, TX 75370 | Oil & Gas Operator | Sep 2026 |
| 20824 | Omni Petroleum Corporation | Austin, TX 78738 | Oil & Gas Operator | Feb 2026 |
| 20825 | Omr Drilling & Acquisition LLC | Albany, KY 42602 | Oil Operator | Dec 2015 |
| 20826 | Omta Operating Limited Liability Company | Corpus Christ, TX 78418 | Oil & Gas Operator | Sep 2026 |
| 20827 | On Pointe Operating LLC | Jones, OK 73049 | Oil & Gas Operator | Sep 2026 |
| 20828 | On-Line Oil Inc | Oklahoma City, OK 73105-5208 | Oil & Gas Operator | Mar 2015 |
| 20829 | Onapa Gas Company LLC | Tulsa, OK 74136-7253 | Gas Operator | Nov 2019 |
| 20830 | Onaroll Operating LLC | Lubbock, TX 79423 | Oil & Gas Operator | Sep 2026 |
| 20831 | Onco Petroleum USA Inc | | Oil Operator | Dec 2009 |
| 20832 | One Epoch Energy, Inc. | Abilene, TX 79604 | Oil & Gas Operator | Mar 2008 |
| 20833 | One Nickel Operating LLC | Hopkinton, MA 01748 | Oil Operator | Sep 2026 |
| 20834 | One Source Financial Services Inc. | McAllen, TX 78501 | Gas Operator | Dec 2019 |
| 20835 | One Tec Operating, LLC | Houston, TX 77002 | Oil & Gas Operator | Nov 2007 |
| 20836 | Oneenergy Partners Operating, LLC | Houston, TX 77019 | Oil & Gas Operator | Nov 2018 |
| 20837 | Oneida Energy Corporation | Tulsa, OK 74137 | Oil & Gas Operator | Jul 2003 |
| 20838 | Oneok Bushton Proces | | Gas Operator | Mar 2007 |
| 20839 | Oneok Energy Service | | Gas Operator | Dec 2008 |
| 20840 | Oneok Exploratio | | Oil & Gas Operator | Mar 1995 |
| 20841 | Oneok Exploration Company | Tulsa, OK 74102 | Oil & Gas Operator | Feb 2017 |
| 20842 | Oneok Field Services Company | Tulsa, OK 74103 | Oil & Gas Operator | Jan 2026 |
| 20843 | Oneok Gas Processing LLC | Tulsa, OK 74103 | Oil & Gas Operator | May 2018 |
| 20844 | Oneok Gas Transportation Co | Tulsa, OK 74121-2089 | Oil & Gas Operator | Oct 2014 |
| 20845 | Oneok Resources Company | Tulsa, OK 74102 | Oil & Gas Operator | Feb 2017 |
| 20846 | Onexxx Prod & Exploration Corp | Jeannette, PA 15644-9691 | Gas Operator | Dec 2025 |
| 20847 | Onnen, Gerhard E. | Yates Center, KS 66783 | Oil Operator | Feb 2002 |
| 20848 | Onpoint Oil & Gas, LLC | Oklahoma City, OK 73170 | Oil & Gas Operator | Jun 2026 |
| 20849 | Onshore Exp Cor-La Nat Res Inc | | Oil & Gas Operator | Oct 1978 |
| 20850 | Onshore Pipeline Const Co Inc | | Oil & Gas Operator | Aug 1998 |
| 20851 | Onshore Royalties LLC | Houston, TX 77269 | Oil & Gas Operator | Jun 2026 |
| 20852 | Onshore, L.L.C. | Wichita, KS 67205 | Oil & Gas Operator | Dec 2009 |
| 20853 | Onyx Energy Corporation | Oklahoma City, OK 73157 | Oil & Gas Operator | May 1994 |
| 20854 | Onyx Energy Dev Of Texas Inc. | | Oil Operator | Dec 1996 |
| 20855 | Onyx Energy Of Texas Inc. | | Oil Operator | Dec 1996 |
| 20856 | Onyx Industries LTD, Inc. | Wichita Falls, TX 76308 | Oil & Gas Operator | Aug 2003 |
| 20857 | Onyx Int'L Exploration LLC | | Oil & Gas Operator | Dec 2015 |
| 20858 | Onyx Producing Company, Inc. | Pampa, TX 79066 | Oil & Gas Operator | Mar 2008 |
| 20859 | Onyx Properties Corp | Oklahoma City, OK 73114 | Oil & Gas Operator | May 2006 |
| 20860 | Onyxx Energy LLC | | Oil & Gas Operator | Mar 2017 |
| 20861 | Onyxx Oil Corpor | | Oil Operator | Jul 1992 |
| 20862 | Oolite Energy Corp | Amarillo, TX 79105 | Oil & Gas Operator | Apr 2022 |
| 20863 | Oonk, Harvey D. | Clymer, NY 14724 | Gas Operator | Dec 2025 |
| 20864 | Opal Oil Inc. | | Oil Operator | Sep 2021 |
| 20865 | Opal Operating Company LLC | Edmond, OK 73013 | Oil & Gas Operator | Sep 2026 |
| 20866 | Opal Resources Operating Co.,LLC | Cypress, TX 77429 | Oil & Gas Operator | Jan 2019 |
| 20867 | Opco LLC | Chase, KS 67524 | Oil Operator | Dec 2019 |
| 20868 | Opco Oil & Gas Co. | Dallas, TX 75231 | Oil & Gas Operator | Aug 2003 |
| 20869 | Opdycke Lease Partners, A General Partnership | Russell, KS 67665 | Oil Operator | May 2026 |
| 20870 | Opef Partnership, A General Partnership | Overland Park, KS 66221 | Oil Operator | Dec 2011 |
| 20871 | Open Door Holdings Inc | Surprise, AZ 85387-2015 | Oil & Gas Operator | Feb 2024 |
| 20872 | Open Door Productions Inc | Muskogee, OK 74401-1032 | Oil & Gas Operator | Apr 2020 |
| 20873 | Open Flow Gas Supply Corp | | Oil & Gas Operator | Dec 2025 |
| 20874 | Open Range Energy LLC | Jones, OK 73049-8744 | Oil & Gas Operator | Dec 2024 |
| 20875 | Operating Engineers Local 17 Training Fund | Lake VIew, NY 14085 | Gas Operator | Dec 2025 |
| 20876 | Operator Unknown | Charleston, WV 253040000 | Oil & Gas Operator | Dec 2021 |
| 20877 | Opes Production Inc | Buffalo, WY 82834 | Gas Operator | Mar 2015 |
| 20878 | Opex Energy, LLC | Houston, TX 77042 | Oil & Gas Operator | Mar 2008 |
| 20879 | Opmi Operating Company | Houston, TX 77057 | Oil & Gas Operator | Jun 2008 |
| 20880 | Ops Group Limited | Houston, TX 77060 | Oil & Gas Operator | Jun 2014 |
| 20881 | Optima Conservation Resources Exploration LLC | | Oil & Gas Operator | Jul 2026 |
| 20882 | Optima Exploration LLC | Tulsa, OK 74116-5664 | Oil & Gas Operator | Mar 2015 |
| 20883 | Optimistic Oil Co. | | Oil & Gas Operator | Dec 1991 |
| 20884 | Optimum Exploration LLC | Dallas, TX 75254 | Oil & Gas Operator | Jan 2026 |
| 20885 | Opubco Resources Of TX Inc | Dallas, TX 75231 | Oil & Gas Operator | Sep 2005 |
| 20886 | Ora Oil Company | | Oil & Gas Operator | May 2017 |
| 20887 | Oracle Oil, LLC | | Oil & Gas Operator | Jul 2013 |
| 20888 | Oracle Resources Oklahoma LP | Dallas, TX 75240-5751 | Oil & Gas Operator | Feb 2008 |
| 20889 | Orange Petroleum Co. | Orangefield, TX 77639 | Oil & Gas Operator | May 1995 |
| 20890 | Orangefield East Corp | Dallas, TX 75382 | Oil Operator | Sep 2026 |
| 20891 | Orangefield Operating Corporation | Dallas, TX 75382 | Oil Operator | Sep 2026 |
| 20892 | Orason Resources Inc | Tulsa, OK 74169-1225 | Oil & Gas Operator | Nov 2006 |
| 20893 | Orb Exploration, L.L.C. | | Oil & Gas Operator | Jun 2017 |
| 20894 | Orbis Energy, L.L.C. | Austin, TX 78746 | Oil & Gas Operator | Oct 2001 |
| 20895 | Orbit Crude, Inc. | Midland, TX 79710 | Oil & Gas Operator | Sep 2026 |
| 20896 | Orbit Enterprises, Inc. | Lovington, NM 88260 | Oil & Gas Operator | Mar 2015 |
| 20897 | Orbit Gas Transmission, Inc | Owensboro, KY 42303 | Oil & Gas Operator | Dec 2023 |
| 20898 | Orbit Petroleum, Inc. | Irving, TX 75038 | Oil & Gas Operator | Sep 2010 |
| 20899 | Orbitron Operating Corp. | Fort Worth, TX 76102 | Oil & Gas Operator | Dec 1995 |
| 20900 | Orbrie Luman | Odessa, TX 79761 | Oil & Gas Operator | Apr 2026 |