| 20801 | Oil Property Man | | Oil & Gas Operator | Jun 1995 |
| 20802 | Oil Property Management, Inc. | Attica, KS 67009 | Oil & Gas Operator | Feb 2021 |
| 20803 | Oil Recovery Systems Inc | Tulsa, OK 74145-4619 | Oil & Gas Operator | Aug 2024 |
| 20804 | Oil Recovery, Inc. | | Oil Operator | Sep 1992 |
| 20805 | Oil Reserves Corp Of America | | Oil & Gas Operator | May 2002 |
| 20806 | Oil Rock Energy Inc. / O.R.E. | Dallas, TX 75208 | Oil & Gas Operator | Nov 2024 |
| 20807 | Oil Rock Oil Company, Inc. | Elizabeth, WV 26143 | Oil & Gas Operator | Dec 2021 |
| 20808 | Oil Rock Resources, LLC | Weatherford, TX 76088 | Oil & Gas Operator | Jan 2024 |
| 20809 | Oil Search Inc | Brookfield, OH 44403 | Oil & Gas Operator | Dec 2023 |
| 20810 | Oil Securities Inc. | | Gas Operator | Dec 2003 |
| 20811 | Oil State Petroleum Inc | Jennings, OK 74038 | Oil & Gas Operator | Sep 2024 |
| 20812 | Oil Tech Producers Corporation | Moundridge, KS 67107 | Gas Operator | Jul 2024 |
| 20813 | Oil Ventures LTD | | Oil & Gas Operator | Jan 2013 |
| 20814 | Oil Well Buyers Corp. | Houston, TX 77056 | Oil & Gas Operator | Jun 2024 |
| 20815 | Oil Well Management Co. | | Oil & Gas Operator | Dec 1989 |
| 20816 | Oil, Gas, Etc. LLC | Katy, TX 77449 | Oil & Gas Operator | Nov 2024 |
| 20817 | Oil,Gas & Other Minerals, Inc. | | Oil & Gas Operator | Mar 1996 |
| 20818 | Oil-Tech Prod Co | | Oil & Gas Operator | Oct 1992 |
| 20819 | Oil-X Corp., The | FT Stockton, TX 79735 | Oil & Gas Operator | Nov 2024 |
| 20820 | Oilbank Production LLC | Norman, OK 73072 | Oil Operator | Aug 2024 |
| 20821 | Oilco Energy Inc | Duncan, OK 73533 | Oil & Gas Operator | Mar 2015 |
| 20822 | Oilco Gas Co LC | Duncan, OK 73534 | Oil & Gas Operator | Dec 2014 |
| 20823 | Oildigger Resources Fund L LLLP | Billings, MT 59101 | Oil & Gas Operator | Sep 2024 |
| 20824 | Oilex Int'L Investments, Inc. | Luling, TX 78648 | Oil & Gas Operator | Nov 2024 |
| 20825 | Oilfield Consultants | | Oil & Gas Operator | Dec 1987 |
| 20826 | Oilfield Management, Inc. (A) | Midland, TX 79702 | Oil & Gas Operator | Nov 2024 |
| 20827 | Oilfield Operating Company | Cushing, OK 74023-1347 | Oil & Gas Operator | Jan 2018 |
| 20828 | Oilfield Research, Inc | | Oil Operator | Dec 2021 |
| 20829 | Oilfield Salvage & Service Company | Littleton, CO 80120 | Oil & Gas Operator | Sep 2024 |
| 20830 | Oilfield Search | | Oil Operator | Mar 1990 |
| 20831 | Oilfield Services And Supply Co. Inc. | | Oil Operator | Sep 1989 |
| 20832 | Oilfield Services, LLC | Winfield, KS 67156 | Oil Operator | Nov 2017 |
| 20833 | Oilfield Truck Service | | Oil Operator | Jun 2014 |
| 20834 | Oilrox Resources LLC | San Antonio, TX 78258 | Oil & Gas Operator | Aug 2023 |
| 20835 | Oilsearch Corporation | Albuquerque, NM 87109 | Oil & Gas Operator | Feb 1994 |
| 20836 | Oiltech Inc | Yuba City, CA 95991 | Oil & Gas Operator | Dec 1984 |
| 20837 | Oiltex, Inc. | Baltimore, MD 21221 | Oil & Gas Operator | Dec 2013 |
| 20838 | Oilton Petroleum Inc | Oilton, OK 74052-0459 | Oil & Gas Operator | Oct 2001 |
| 20839 | Oilton Resources, Inc. | Laredo, TX 78041 | Oil & Gas Operator | Nov 2024 |
| 20840 | Oilwell Acquisition Co. | | Oil & Gas Operator | Jun 1999 |
| 20841 | Oilwell Operator | | Gas Operator | Dec 1994 |
| 20842 | Oilwell Operators, Inc. | Pampa, TX 79066 | Oil & Gas Operator | Nov 2024 |
| 20843 | Oily Dog Operators Texas, LLC | Austin, TX 78746 | Oil Operator | Nov 2024 |
| 20844 | Ojai Oil Company | Camarillo, CA 93012 | Oil & Gas Operator | Sep 2024 |
| 20845 | Ojb, Inc. | Buda, TX 78610 | Oil & Gas Operator | Mar 2013 |
| 20846 | Ojt, LLC | Richmond, TX 77469 | Oil Operator | Nov 2024 |
| 20847 | Ok Arena Operating Company | Oklahoma City, OK 73101 | Oil & Gas Operator | Nov 2024 |
| 20848 | Ok Oil Company, Inc. | Bivins, TX 75555 | Oil & Gas Operator | Feb 2013 |
| 20849 | Ok Operating Co | Midland, TX 79702 | Oil & Gas Operator | Aug 1999 |
| 20850 | Ok-La-Tex Production, Inc. | | Oil & Gas Operator | Jan 1982 |
| 20851 | Okc Energy Corporation | Oklahoma City, OK 73120-3119 | Oil & Gas Operator | Nov 2014 |
| 20852 | Okemah Production Inc | | Oil Operator | Dec 2005 |
| 20853 | Okie Crude Company | Tulsa, OK 74103 | Oil & Gas Operator | Sep 2024 |
| 20854 | Okie Oil Inc | Sapulpa, OK 74067-0290 | Oil & Gas Operator | Mar 2011 |
| 20855 | Okie Operating Company, LTD. | Tulsa, OK 74103 | Oil & Gas Operator | Nov 2024 |
| 20856 | Okkatahula, Inc. | | Oil Operator | Nov 1978 |
| 20857 | Okla Petroleum Energies Corp | | Oil Operator | Jan 2013 |
| 20858 | Okla Petroleum Reclaimers Inc | Kellyville, OK 74039 | Oil Operator | Jul 2020 |
| 20859 | Okla Sub-Surface Pump & Supply Co | Seminole, OK 74804 | Oil & Gas Operator | Sep 2024 |
| 20860 | Okla. Magic Circle Energy Corp. | Shawnee, OK 74801 | Oil & Gas Operator | Jul 2004 |
| 20861 | Oklahoma & Northwestern Co. | Oklahoma City, OK 73102 | Oil & Gas Operator | Jan 1997 |
| 20862 | Oklahoma Arrowhead Energy, Inc. | Nichols Hill, OK 73116 | Oil & Gas Operator | Sep 1996 |
| 20863 | Oklahoma Basic Economy Corp | Houston, TX 77002-6003 | Oil & Gas Operator | Apr 2020 |
| 20864 | Oklahoma Cellulose Inc | Cleveland, OK 74020 | Oil Operator | Sep 2024 |
| 20865 | Oklahoma Crude Inc | Broken Arrow, OK 74012 | Oil & Gas Operator | Apr 2024 |
| 20866 | Oklahoma Crude Reclaimers, LLC | | Oil Operator | Sep 2024 |
| 20867 | Oklahoma Ea II, L.L.C. | Oklahoma City, OK 73102 | Oil & Gas Operator | Dec 2004 |
| 20868 | Oklahoma Energy & Exploration, Inc. | Tulsa, OK 74114 | Oil Operator | Jan 1996 |
| 20869 | Oklahoma Energy Acquisitions LP | Houston, TX 77094-1900 | Oil & Gas Operator | Aug 2024 |
| 20870 | Oklahoma Energy Development Co | | Oil & Gas Operator | Sep 2008 |
| 20871 | Oklahoma Energy Exchange LLC | Duncan, OK 73534-1105 | Oil & Gas Operator | Sep 2012 |
| 20872 | Oklahoma Energy LLC | Skiatook, OK 74070-3998 | Oil Operator | Jul 2024 |
| 20873 | Oklahoma Equipment & Salvage | Oklahoma City, OK 73120-5903 | Oil & Gas Operator | Mar 2015 |
| 20874 | Oklahoma Gas & Oil Corporation | Okemah, OK 74859 | Oil Operator | Oct 2018 |
| 20875 | Oklahoma Liquid Resources Inc | Collinsville, OK 74021 | Oil & Gas Operator | Aug 2024 |
| 20876 | Oklahoma Marlin Oil Corporation | Oklahoma City, OK 73113 | Oil & Gas Operator | Feb 2020 |
| 20877 | Oklahoma Natural Resources Inc | Woodward, OK 73801 | Oil & Gas Operator | Sep 1996 |
| 20878 | Oklahoma O & G Royalties Inc | Duncan, OK 73533 | Oil & Gas Operator | Nov 2000 |
| 20879 | Oklahoma Oil & Gas MGMT Inc | Edmond, OK 73083-6786 | Oil & Gas Operator | Aug 2024 |
| 20880 | Oklahoma Oil And Gas Resources LLC | Guthrie, OK 73044-8095 | Oil & Gas Operator | Sep 2024 |
| 20881 | Oklahoma Oil Company | Dallas, TX 75206 | Oil & Gas Operator | Aug 2013 |
| 20882 | Oklahoma Oil Tactics Inc | Edmond, OK 73003-1351 | Oil & Gas Operator | Mar 2015 |
| 20883 | Oklahoma Operating Company | Midland, TX 79708 | Oil & Gas Operator | Nov 2024 |
| 20884 | Oklahoma Operating, LLC | Holliday, TX 76366 | Oil Operator | Nov 2003 |
| 20885 | Oklahoma Petroleum Allies LLC | Ardmore, OK 73401 | Oil Operator | Oct 2023 |
| 20886 | Oklahoma Petroleum MGMT Corp | Tulsa, OK 74119 | Oil & Gas Operator | Jun 1993 |
| 20887 | Oklahoma Prime Energy LLC | Ardmore, OK 73401 | Oil Operator | May 2020 |
| 20888 | Oklahoma RB Operating Company | Midland, TX 79701 | Oil & Gas Operator | Jan 1998 |
| 20889 | Oklahoma Rig & Salvage, Inc. | Oklahoma City, OK 73114 | Oil & Gas Operator | Mar 2015 |
| 20890 | Oklahoma SWD Systems Inc | Odessa, TX 79762-8132 | Oil & Gas Operator | Aug 2024 |
| 20891 | Oklahoma Tank Service Inc | Oklahoma City, OK 73143 | Oil Operator | Aug 1997 |
| 20892 | Okland Oil Company | Oklahoma City, OK 73102-9022 | Oil & Gas Operator | Sep 2024 |
| 20893 | Oklaoleum Oil And Gas Inc | Bristow, OK 74010-0057 | Oil Operator | Jan 2016 |
| 20894 | Oklatex Energy, Inc. | Beaumont, TX 77702 | Oil Operator | Nov 2024 |
| 20895 | Okmar Oil Compan | | Oil & Gas Operator | Feb 1995 |
| 20896 | Okmar Oil Company | Marietta, OH 45750 | Oil & Gas Operator | Jun 2005 |
| 20897 | Okreek Oil Company | Weatherford, TX 76086 | Oil & Gas Operator | Nov 2024 |
| 20898 | Okt Petroleum Company Inc | Oklahoma City, OK 73118-7425 | Oil & Gas Operator | Oct 2013 |
| 20899 | Okt Resources, LLC | Edmond, OK 73013 | Oil & Gas Operator | Nov 2024 |
| 20900 | Oktex Operating LLC | Edmond, OK 73013-1961 | Oil & Gas Operator | May 2020 |