| 20901 | Opal Oil Inc. | | Oil Operator | Sep 2021 |
| 20902 | Opal Operating Company LLC | Oklahoma City, OK 73142 | Oil & Gas Operator | Sep 2024 |
| 20903 | Opal Resources Operating Co.,LLC | Cypress, TX 77429 | Oil & Gas Operator | Jan 2019 |
| 20904 | Opco LLC | Chase, KS 67524 | Oil Operator | Dec 2019 |
| 20905 | Opco Oil & Gas Co. | Dallas, TX 75231 | Oil & Gas Operator | Aug 2003 |
| 20906 | Opdycke Lease Partners, A General Partnership | Russell, KS 67665 | Oil Operator | May 2024 |
| 20907 | Opef Partnership, A General Partnership | Overland Park, KS 66221 | Oil Operator | Dec 2011 |
| 20908 | Open Door Holdings Inc | Surprise, AZ 85387-2015 | Oil & Gas Operator | Feb 2024 |
| 20909 | Open Door Productions Inc | Muskogee, OK 74401-1032 | Oil & Gas Operator | Apr 2020 |
| 20910 | Open Flow Gas Supply Corp | Du Bois, PA 15801-2442 | Oil & Gas Operator | Dec 2022 |
| 20911 | Open Range Energy LLC | Jones, OK 73049-8744 | Oil & Gas Operator | Jul 2024 |
| 20912 | Operating Engineers Local 17 Training Fund | Lake VIew, NY 14085 | Gas Operator | Dec 2023 |
| 20913 | Operating Services Inc | | Oil Operator | Sep 2003 |
| 20914 | Operator Unknown | Charleston, WV 25304-0000 | Oil & Gas Operator | Dec 2021 |
| 20915 | Opes Production Inc | Buffalo, WY 82834 | Gas Operator | Mar 2015 |
| 20916 | Opex Energy, LLC | Houston, TX 77042 | Oil & Gas Operator | Mar 2008 |
| 20917 | Opmi Operating Company | Houston, TX 77057 | Oil & Gas Operator | Jun 2008 |
| 20918 | Ops Group Limited | Houston, TX 77060 | Oil & Gas Operator | Jun 2014 |
| 20919 | Optima Conservation Resources Exploration LLC | | Oil & Gas Operator | Jul 2024 |
| 20920 | Optima Exploration LLC | Tulsa, OK 74116-5664 | Oil & Gas Operator | Mar 2015 |
| 20921 | Optimistic Oil Co. | | Oil & Gas Operator | Dec 1991 |
| 20922 | Optimum Exploration LLC | Dallas, TX 75240 | Oil & Gas Operator | Sep 2024 |
| 20923 | Opubco Resources Of TX Inc | Dallas, TX 75231 | Oil & Gas Operator | Sep 2005 |
| 20924 | Ora Oil Company | | Oil & Gas Operator | May 2017 |
| 20925 | Oracle Oil, LLC | | Oil & Gas Operator | Jul 2013 |
| 20926 | Oracle Resources Oklahoma LP | Dallas, TX 75240-5751 | Oil & Gas Operator | Feb 2008 |
| 20927 | Orange Petroleum Co. | Orangefield, TX 77639 | Oil & Gas Operator | May 1995 |
| 20928 | Orangefield Operating Corporatio | Dallas, TX 75241 | Oil Operator | Sep 2024 |
| 20929 | Orason Resources Inc | Tulsa, OK 74169-1225 | Oil & Gas Operator | Nov 2006 |
| 20930 | Orb Exploration, L.L.C. | | Oil & Gas Operator | Jun 2017 |
| 20931 | Orbis Energy, L.L.C. | Austin, TX 78746 | Oil & Gas Operator | Oct 2001 |
| 20932 | Orbit Crude, Inc. | Midland, TX 79710 | Oil & Gas Operator | Sep 2024 |
| 20933 | Orbit Enterprises, Inc. | Lovington, NM 88260 | Oil & Gas Operator | Mar 2015 |
| 20934 | Orbit Gas Transmission, Inc | Owensboro, KY 42303 | Oil & Gas Operator | Dec 2021 |
| 20935 | Orbit Petroleum, Inc. | Irving, TX 75038 | Oil & Gas Operator | Sep 2010 |
| 20936 | Orbitron Operating Corp. | Fort Worth, TX 76102 | Oil & Gas Operator | Dec 1995 |
| 20937 | Orbrie Luman | Odessa, TX 79761 | Oil & Gas Operator | Aug 2024 |
| 20938 | Orca Operating Company LLC | Houston, TX 77056 | Oil & Gas Operator | Jul 2024 |
| 20939 | Oren Stone | Erick, OK 73645-4542 | Gas Operator | Jun 2022 |
| 20940 | Organic Energy Company LLC | | Oil & Gas Operator | Jul 2024 |
| 20941 | Origin Prod Co Gonzales Prop LLC | New Braunfels, TX 78132 | Oil & Gas Operator | Sep 2024 |
| 20942 | Origin Production Company, Inc. | New Braunfels, TX 78132 | Oil & Gas Operator | Sep 2024 |
| 20943 | Origin Production Group LLC | Luling, TX 78648 | Oil Operator | Sep 2024 |
| 20944 | Oringderff, Alma Oil Properties | Dallas, TX 75225 | Oil & Gas Operator | Mar 2012 |
| 20945 | Oriole Operating LLC | Wichita Falls, TX 76308 | Oil Operator | Sep 2024 |
| 20946 | Orion Energen Inc. | Austin, TX 78731 | Oil & Gas Operator | Jul 2023 |
| 20947 | Orion Energy Corp | MT Vernon, IL 62864 | Oil & Gas Operator | Dec 1984 |
| 20948 | Orion Energy Partners LP | Denver, CO 80202 | Oil & Gas Operator | Jul 2024 |
| 20949 | Orion Exploration LLC | Tulsa, OK 74105-5153 | Oil & Gas Operator | Apr 2015 |
| 20950 | Orion Exploration Partners LLC | Tulsa, OK 74105-5153 | Oil & Gas Operator | Jun 2024 |
| 20951 | Orion Oil & Gas Prop | Roswell, NM 88202 | Oil & Gas Operator | Apr 1998 |
| 20952 | Orion Oil & Gas Properties | Amarillo, TX 79109 | Gas Operator | Oct 2000 |
| 20953 | Orion Oil & Gas, LLC | Houston, TX 77042 | Oil & Gas Operator | Oct 2007 |
| 20954 | Orion Oil And Gas Corporation | Houston, TX 77082 | Oil & Gas Operator | Sep 2024 |
| 20955 | Orion Petro Corp | MT Vernon, IL 62864 | Oil & Gas Operator | Dec 2016 |
| 20956 | Orisol Oil Co. | Houston, TX 77206 | Oil Operator | Jun 2000 |
| 20957 | Orla Petco Inc & Hopi Drilling Co | Midland, TX 79702 | Oil Operator | Sep 2004 |
| 20958 | Orla Petco, Inc. | Midland, TX 79702 | Oil & Gas Operator | Sep 2024 |
| 20959 | Orland Oil & Gas LLC | FT Lauderdale, FL 33305 | Oil Operator | Sep 2024 |
| 20960 | Orleans Exploration Co., Inc. | | Oil & Gas Operator | Aug 1990 |
| 20961 | Orloski John C | Bartlesville, OK 74006 | Oil & Gas Operator | Jun 2024 |
| 20962 | Ormand, Don R. | Midland, TX 79705 | Oil & Gas Operator | Jan 2016 |
| 20963 | Oro Negro Inc. | | Oil & Gas Operator | Dec 2004 |
| 20964 | Oro Resources, LLC | Austin, TX 78746 | Oil & Gas Operator | Sep 2024 |
| 20965 | Orr Energy LLC | | Oil & Gas Operator | Nov 2012 |
| 20966 | Orr Production Company | Austin, TX 78746 | Oil & Gas Operator | Dec 2000 |
| 20967 | Orr Robert W Jr | Zanesville, OH 43702-2683-2683 | Oil & Gas Operator | Dec 2023 |
| 20968 | Orr, Jr., Donald R. | Batavia, NY 14020 | Gas Operator | Dec 2023 |
| 20969 | Orsburn, Wade Inc. | Gainesville, TX 76240 | Oil & Gas Operator | Nov 2002 |
| 20970 | Orson Leasing & Supply | Rockdale, TX 76567 | Oil & Gas Operator | Dec 2006 |
| 20971 | Orth Oil Company, Inc. | Cisco, TX 76437 | Oil & Gas Operator | Sep 2024 |
| 20972 | Orville S Slaughter Jr | Denver, CO 80205 | Oil & Gas Operator | Aug 2000 |
| 20973 | Orwig Oil Company Inc | Bradenton, FL 34212 | Oil & Gas Operator | Dec 2022 |
| 20974 | Orx Resources, Inc. | | Oil & Gas Operator | Dec 2009 |
| 20975 | Orx Resources, L.L.C. | Houston, TX 77067 | Oil & Gas Operator | Sep 2024 |
| 20976 | Oryx Crude Trading & Transporation LP | Dallas, TX 75221 | Oil & Gas Operator | Jun 1999 |
| 20977 | Oryx Energy Comp | | Oil & Gas Operator | Apr 1991 |
| 20978 | Oryx Energy Company | Dallas, TX 75221 | Oil & Gas Operator | May 2002 |
| 20979 | Os&S Operating Inc. | Electra, TX 76360 | Oil & Gas Operator | Sep 2024 |
| 20980 | Osa Oil & Gas LLC | Tulsa, OK 74131 | Oil & Gas Operator | Aug 2023 |
| 20981 | Osage Energy LLC | Colony, KS 66015 | Oil Operator | Nov 2023 |
| 20982 | Osage Energy Resources LLC | Bartlesville, OK 74005-2527 | Oil & Gas Operator | Jun 2024 |
| 20983 | Osage Exploration & Development Inc | San Diego, CA 92131-3807 | Oil & Gas Operator | Oct 2016 |
| 20984 | Osage Hot Oil Service | Newcastle, WY 82701 | Oil & Gas Operator | Jul 1997 |
| 20985 | Osage Oil & Transportation Inc | Cleveland, OK 74020 | Oil & Gas Operator | Nov 2000 |
| 20986 | Osage Operating | Virginia Beach, VA 23452 | Oil & Gas Operator | Oct 2003 |
| 20987 | Osage Operating Company LLC | Seattle, WA 98133 | Oil Operator | May 2006 |
| 20988 | Osage Partners LLC | | Oil & Gas Operator | Jul 2024 |
| 20989 | Osage Petroleum Corporation | Saint Louis, MO 63131-4691 | Oil & Gas Operator | Mar 2009 |
| 20990 | Osage Resources, LLC | Wichita, KS 67202 | Oil & Gas Operator | Mar 2024 |
| 20991 | Osair Inc | Mentor, OH 44061 | Oil & Gas Operator | Dec 2021 |
| 20992 | Osborn Energy, L.L.C. | Bucyrus, KS 66013 | Oil & Gas Operator | Jul 2017 |
| 20993 | Osborn Heirs Co | San Antonio, TX 78217 | Oil & Gas Operator | Aug 2024 |
| 20994 | Osborn Heirs Com | | Oil & Gas Operator | May 1995 |
| 20995 | Osborn Heirs Company LTD | San Antonio, TX 78217 | Oil & Gas Operator | May 2024 |
| 20996 | Osborn Oil & Gas | | Oil & Gas Operator | Jun 1991 |
| 20997 | Osborn,W.B. Oil & Gas Operations | San Antonio, TX 78217 | Oil & Gas Operator | Sep 2024 |
| 20998 | Osborne Oil Co. | Dallas, TX 75244 | Oil & Gas Operator | Aug 2003 |
| 20999 | Osburn Gerald Dba Ozzy & Son Oil & Gas | Drumright, OK 74030-5467 | Oil Operator | Oct 2020 |
| 21000 | Oscar Oil Company | Iowa Park, TX 76367 | Oil & Gas Operator | Sep 2004 |