| 801 | Century Exploration Company | | Oil & Gas Operator | Dec 2003 |
| 802 | Century Exploration Houston, Inc | The Woodlands, TX 77380 | Oil & Gas Operator | Oct 2011 |
| 803 | Century Exploration Houston, LLC | Austin, TX 78702 | Oil & Gas Operator | Jan 2016 |
| 804 | Century Exploration N.O. LLC | | Oil & Gas Operator | Jun 2017 |
| 805 | Century Exploration N.O., Inc. | | Oil & Gas Operator | Sep 2011 |
| 806 | Century Mineral Corporation | | Oil & Gas Operator | Dec 1990 |
| 807 | Century Offshore MGMT. Corp. | | Oil & Gas Operator | Dec 1999 |
| 808 | Century Oil, Inc. | | Oil Operator | Apr 2022 |
| 809 | Cerro Oil Co., Inc. | | Oil Operator | Dec 1987 |
| 810 | Chadco, Inc. | | Oil Operator | Dec 2024 |
| 811 | Chain Oil & Gas, Inc. | Houston, TX 77024 | Oil & Gas Operator | Mar 2025 |
| 812 | Challenge Operating Inc | Tulsa, OK 74103 | Oil & Gas Operator | Feb 2024 |
| 813 | Chambers Exploration Inc. | | Oil & Gas Operator | Dec 1986 |
| 814 | Champ Operating Company | Dallas, TX 75208 | Oil & Gas Operator | Oct 2020 |
| 815 | Champlin Petroleum Co. | Rock Springs, WY 82902 | Oil & Gas Operator | Mar 1991 |
| 816 | Channel Exploration Company | | Oil & Gas Operator | Feb 1997 |
| 817 | Chanse Energy Corporation | Shreveport, LA 71165-1572 | Oil & Gas Operator | Sep 2021 |
| 818 | Chaparral Energy, Inc. | Oklahoma City, OK 73114 | Oil & Gas Operator | Dec 2009 |
| 819 | Chaparral Energy, L.L.C. | Oklahoma City, OK 73142 | Oil & Gas Operator | Mar 2025 |
| 820 | Chaparral Expl & C L Morris In | | Oil & Gas Operator | Nov 1994 |
| 821 | Chaparral Exploration, Inc. | | Oil & Gas Operator | Jun 2000 |
| 822 | Chaparral Operating, Inc. | Shreveport, LA 71166 | Oil & Gas Operator | Mar 2025 |
| 823 | Charing Cross Properties | | Oil Operator | Aug 1995 |
| 824 | Charles A. O'Niell, Jr. | | Oil & Gas Operator | Apr 2001 |
| 825 | Charles B. Bice | | Oil & Gas Operator | Jul 1983 |
| 826 | Charles E. Mayfield | | Oil & Gas Operator | Mar 2001 |
| 827 | Charles F. Word & Associates | | Oil Operator | Dec 1978 |
| 828 | Charles G. Dannelly | | Oil & Gas Operator | Mar 1998 |
| 829 | Charles Holston, Inc. | | Oil Operator | Jan 2025 |
| 830 | Charles Holston, Inc. Dba GTTS | | Oil Operator | Apr 2009 |
| 831 | Charles M. Nolan | | Oil Operator | Aug 1984 |
| 832 | Charleston Oil & Gas, Inc. | | Oil & Gas Operator | Mar 1997 |
| 833 | Chateau Oil And Gas, Inc. | Dallas, TX 75225 | Oil & Gas Operator | Feb 2017 |
| 834 | CHC Energy, LLC | | Gas Operator | Nov 2012 |
| 835 | Cheniere Petroleum Corporation | | Oil & Gas Operator | Feb 1989 |
| 836 | Chesapeake Operating LLC | Oklahoma City, OK 73154 | Oil & Gas Operator | Mar 2025 |
| 837 | Chesapeake Operating, Inc. | Oklahoma City, OK 73154 | Oil & Gas Operator | Nov 2024 |
| 838 | Chester Floyd | | Oil Operator | Feb 1996 |
| 839 | Chestnut Exploration And Production, Inc. | Richardson, TX 78081 | Oil & Gas Operator | Nov 2020 |
| 840 | Chestnut Petroleum, Inc. | Richardson, TX 75080 | Oil & Gas Operator | Nov 2011 |
| 841 | Chevron Pipe Line Company | Houston, TX 77001 | Oil Operator | Feb 2015 |
| 842 | Chevron USA Inc | Midland, TX 79706 | Oil & Gas Operator | Mar 2025 |
| 843 | Chiles Oil Field Supply | | Oil & Gas Operator | Jan 2025 |
| 844 | Chinn Exploration Company | Longview, TX 75605 | Oil & Gas Operator | Nov 2015 |
| 845 | Chisos, LTD | Houston, TX 77098 | Oil & Gas Operator | Mar 2025 |
| 846 | Cholla Resources, Inc. | Denver, CO 80202 | Oil & Gas Operator | Jan 1997 |
| 847 | Christeve Oil Company, Inc. | Houston, TX 77068 | Oil & Gas Operator | Dec 2022 |
| 848 | Christopher Oil & Gas Inc | Fulshear, TX 77441 | Oil & Gas Operator | Apr 2015 |
| 849 | Chroma Operating, Inc. | Washington, DC 20036 | Oil & Gas Operator | Jun 2016 |
| 850 | Churchill Energy Inc | | Oil & Gas Operator | Sep 2020 |
| 851 | Cibco Resources, LLC | | Oil & Gas Operator | Nov 2024 |
| 852 | Cibolo Energy Operating, Inc. | Bulverde, TX 78163 | Oil & Gas Operator | Mar 2025 |
| 853 | Cico Oil & Gas Company | Houston, TX 77057 | Oil & Gas Operator | Aug 2019 |
| 854 | Ciera Resources, Inc. | | Gas Operator | Nov 1998 |
| 855 | Cimarex Energy Co | Midland, TX 79706 | Oil & Gas Operator | Mar 2025 |
| 856 | Cimarex Energy Co Of Colorado | Midland, TX 79706 | Oil & Gas Operator | Mar 2025 |
| 857 | Cimic Energy, LLC | | Oil Operator | Jan 2025 |
| 858 | Cinder Production Company | | Oil & Gas Operator | Apr 2014 |
| 859 | Cisco Petroleum, Inc. | | Oil & Gas Operator | Oct 2010 |
| 860 | Citation Oil & Gas Corp. | Houston, TX 77269 | Oil & Gas Operator | Mar 2025 |
| 861 | Cities Service Company | | Oil & Gas Operator | Mar 1983 |
| 862 | Cities Service Oil & Gas Corp | | Oil & Gas Operator | Mar 1988 |
| 863 | Cities Service Oil Co. | | Oil & Gas Operator | Dec 1986 |
| 864 | Cits BK & Trust Of Springhill | | Oil & Gas Operator | Jun 1990 |
| 865 | Civego, Inc. | | Oil & Gas Operator | Jul 1994 |
| 866 | Clarence F. Routon, Jr. | | Oil Operator | Apr 1990 |
| 867 | Clark Oil Producing Company | | Oil & Gas Operator | Oct 1979 |
| 868 | Claron Corporation | Houston, TX 77219 | Oil & Gas Operator | Mar 2025 |
| 869 | Classic Hydrocarbons, Inc. | | Gas Operator | Dec 2007 |
| 870 | Classic Oil & Gas, Inc. | Tyler, TX 75701 | Oil & Gas Operator | Jan 2004 |
| 871 | Claude Debeaux, Jr. Et Al | | Oil Operator | Dec 1999 |
| 872 | Claude S. Hinds | | Oil Operator | Aug 1985 |
| 873 | Clayton W. Williams, Jr. | | Oil & Gas Operator | Sep 1986 |
| 874 | Clayton W. Williams, Jr., Inc. | | Oil & Gas Operator | May 1993 |
| 875 | Clayton Williams Energy, Inc. | Houston, TX 77070 | Oil & Gas Operator | Apr 2017 |
| 876 | Clear Lake Oil Co. | | Oil Operator | Jan 2025 |
| 877 | Clearly Petroleum, LLC | Houston, TX 77086 | Oil & Gas Operator | Jun 2020 |
| 878 | Clements Energy, Inc. | | Oil & Gas Operator | Oct 1987 |
| 879 | Clements-B & MCK - Luffey | | Gas Operator | Apr 1979 |
| 880 | Click Corp | Monroe, LA 71207 | Oil & Gas Operator | Jan 2025 |
| 881 | Cliffs Drilling Company | | Oil & Gas Operator | Dec 1984 |
| 882 | Cliffs Oil And Gas Company | | Oil & Gas Operator | Oct 1997 |
| 883 | Cliffwood Production Co. | Houston, TX 77090 | Oil & Gas Operator | Aug 2013 |
| 884 | CLK Energy Partners, LLC | | Oil & Gas Operator | Aug 2018 |
| 885 | Clovelly DRLG & Dev Co Inc | | Oil & Gas Operator | Oct 1983 |
| 886 | Clovelly Oil Co. LLC | | Oil & Gas Operator | Nov 2024 |
| 887 | Clovelly Oil Co., Inc. | | Oil & Gas Operator | Nov 2008 |
| 888 | Clovelly Oil Co., Inc. - Ripco | | Oil & Gas Operator | Nov 1991 |
| 889 | Clover Energy Corp | | Oil & Gas Operator | May 1980 |
| 890 | CM Oil Co., L.L.C. | | Oil Operator | Jan 2025 |
| 891 | CMS Nomeco Oil & Gas Co. | Jackson, MI 49201 | Oil & Gas Operator | Jan 2015 |
| 892 | CMS Oil And Gas Company | Jackson, MI 49201 | Oil & Gas Operator | Oct 2002 |
| 893 | CN Operating Company | Drumright, OK 74030 | Oil & Gas Operator | Nov 1998 |
| 894 | CNC Oil Co., Inc. | | Oil Operator | Aug 1991 |
| 895 | CNG Producing Co.-Tulsa Div. | | Oil & Gas Operator | Jun 1986 |
| 896 | CNG Producing Company | New Orleans, LA 70112 | Oil & Gas Operator | Dec 2015 |
| 897 | CNR Resources, Inc. | Houston, TX 77002-4103 | Oil & Gas Operator | May 2005 |
| 898 | Co-Wil-Co, Incorporated | | Oil Operator | Dec 1990 |
| 899 | Coalinga Corporation | Houston, TX 77002 | Oil & Gas Operator | May 1999 |
| 900 | Coast Exploration Co. | | Oil & Gas Operator | Nov 1997 |