| 1001 | Corum Production Co.-Tepco | | Oil & Gas Operator | Dec 1989 |
| 1002 | Corum Production Company | Houston, TX 77002 | Oil & Gas Operator | Feb 2026 |
| 1003 | Costa Energy, LLC | Irving, TX 75063 | Oil & Gas Operator | Feb 2026 |
| 1004 | Costilla Petroleum Corporation | Midland, TX 79702 | Oil & Gas Operator | Mar 2015 |
| 1005 | Coteau Energy LLC | | Oil & Gas Operator | Dec 2024 |
| 1006 | Cotton Petroleum Corporation | Tulsa, OK 74102 | Oil & Gas Operator | Jan 2005 |
| 1007 | Cougar Exploration, Inc. | | Oil & Gas Operator | Jun 1988 |
| 1008 | Courtney Oil Co. | | Oil Operator | Dec 1998 |
| 1009 | Coushatta Oil & Gas Inc. | | Oil & Gas Operator | Jan 2007 |
| 1010 | Covey Energy, Inc. | | Oil & Gas Operator | Jun 1998 |
| 1011 | Covey Park Gas LLC | | Oil & Gas Operator | Aug 2019 |
| 1012 | Cox & Perkins Exploration, Inc. | Houston, TX 77057 | Oil & Gas Operator | Feb 2026 |
| 1013 | Cox Oil & Gas Inc | Dallas, TX 75201 | Oil & Gas Operator | Mar 2014 |
| 1014 | Cox Operating, L.L.C. | | Oil & Gas Operator | Jan 2024 |
| 1015 | Cox Resources Corporation | Dallas, TX 75244 | Oil & Gas Operator | Mar 2015 |
| 1016 | Coy W. Hale | | Oil Operator | Nov 2024 |
| 1017 | CPBG, LLC | | Oil Operator | Oct 2019 |
| 1018 | Cpi 5, L.L.C | | Oil Operator | Dec 2023 |
| 1019 | Cpi Operating Co. | | Oil & Gas Operator | Mar 2003 |
| 1020 | Cpi Operating Company, LLC | | Oil Operator | Jan 2025 |
| 1021 | Cra International, LTD | | Oil & Gas Operator | Mar 1983 |
| 1022 | Crab Run Gas Company | | Oil & Gas Operator | Feb 1982 |
| 1023 | Crain & Dore Production Co Inc | | Oil & Gas Operator | Oct 1990 |
| 1024 | Cranford Exploration, Inc. | | Oil & Gas Operator | Jul 2002 |
| 1025 | Crawford Energy Operating Co | Houston, TX 77056 | Oil & Gas Operator | Aug 2008 |
| 1026 | Crawford Hughes Operating Co. | The Woodlands, TX 77380 | Oil & Gas Operator | Feb 2026 |
| 1027 | Crebbs Oil Company | Batson, TX 77519 | Oil & Gas Operator | Jun 2024 |
| 1028 | Credo Petroleum Corporation | Denver, CO 80202 | Oil & Gas Operator | Jan 2013 |
| 1029 | Creek Operating Company, Inc. | Dallas, TX 75205 | Oil & Gas Operator | Sep 1998 |
| 1030 | Creole Operating, LLC | | Oil & Gas Operator | Dec 2024 |
| 1031 | Crescent Drilling Company, Inc. | | Gas Operator | Dec 2024 |
| 1032 | Crescent DRLG & DVLPMNT, Inc. | | Oil & Gas Operator | Oct 1992 |
| 1033 | Crescent Energy Company | | Oil Operator | May 1993 |
| 1034 | Crescent Pass Energy, LLC | Houston, TX 77070 | Oil & Gas Operator | Feb 2026 |
| 1035 | Creslenn Oil Co | | Oil & Gas Operator | Nov 1998 |
| 1036 | Crest Resources & Expl. Corp. | Houston, TX 77079 | Oil & Gas Operator | Dec 1998 |
| 1037 | Crestmont Operating LLC | New York, NY 10151 | Oil Operator | Feb 2026 |
| 1038 | Crimson Explor Operating, Inc. | | Oil & Gas Operator | Dec 2009 |
| 1039 | Criswell E. White | | Gas Operator | Jun 2015 |
| 1040 | Cross Development Co. | | Oil Operator | Dec 1989 |
| 1041 | Cross Development-MMHS PRTSHP. | | Oil Operator | May 1987 |
| 1042 | Cross Development1984-1 PRTSHP | | Oil & Gas Operator | Sep 1990 |
| 1043 | Cross Timbers Operating Company | Fort Worth, TX 76102 | Oil & Gas Operator | Sep 2025 |
| 1044 | Crossroads Energy Development, LLC | | Oil Operator | Mar 2018 |
| 1045 | Crosstex Lig, LLC | | Oil Operator | Mar 2014 |
| 1046 | Crosstex Processing SVCS, LLC | | Oil Operator | Mar 2014 |
| 1047 | Crosstex Treating Services, L.P. | | Oil Operator | Sep 2009 |
| 1048 | Crow-Eason | | Oil & Gas Operator | Feb 1984 |
| 1049 | Crow-Gulf Coast Venture | | Oil & Gas Operator | Aug 1985 |
| 1050 | Crow-Pittman | | Oil Operator | Aug 1993 |
| 1051 | Crowder Oil Co. | | Oil Operator | Sep 2008 |
| 1052 | Crowder Oil L.L.C. | | Oil Operator | Apr 2015 |
| 1053 | Crown Central Petroleum Corp | Richmond, TX 77469 | Oil & Gas Operator | Dec 1999 |
| 1054 | Crown Zellerbach | | Oil & Gas Operator | May 1986 |
| 1055 | Crown Zellerbach & Newton | | Oil Operator | May 1986 |
| 1056 | Crumpler Oil | | Oil & Gas Operator | Nov 2024 |
| 1057 | Crystal Gas, L.L.C. | | Oil & Gas Operator | Apr 2000 |
| 1058 | Crystal Oil And Land Company | | Oil & Gas Operator | May 1992 |
| 1059 | Crystal Oil Company | Shreveport, LA 71120 | Oil & Gas Operator | Jul 1995 |
| 1060 | CSC Energy Corp. | | Oil & Gas Operator | Dec 2009 |
| 1061 | CSC, Inc. | | Oil Operator | Jan 2000 |
| 1062 | CSL Exploration, LP | Houston, TX 77002 | Oil & Gas Operator | Apr 2018 |
| 1063 | CSM, Inc. | | Gas Operator | Oct 1990 |
| 1064 | CSV Holdings, Inc. | | Oil & Gas Operator | Dec 2014 |
| 1065 | CSX Oil & Gas Corporation | Houston, TX 77210-4326 | Oil & Gas Operator | Mar 1993 |
| 1066 | Cti Associates | | Gas Operator | Jan 1990 |
| 1067 | Cuatro Petro Corp. | Richardson, TX 75080 | Oil & Gas Operator | Feb 2026 |
| 1068 | Culoco, Inc. | Dallas, TX 75374 | Oil & Gas Operator | Nov 2024 |
| 1069 | Cummins & Walker Oil Co., Inc. | Austin, TX 78746 | Oil & Gas Operator | Jan 2021 |
| 1070 | Curt Weaver Et Al | | Oil Operator | Apr 1982 |
| 1071 | Curtis Beard & Huston P. Ganey | | Oil Operator | Mar 1987 |
| 1072 | Curtis F. Adams | | Oil & Gas Operator | Oct 2024 |
| 1073 | Custer K. Primos | | Oil & Gas Operator | Oct 2002 |
| 1074 | CWJ Operating Co., Inc. | | Oil & Gas Operator | Sep 2001 |
| 1075 | CX Operating, Inc. | | Oil & Gas Operator | Oct 2023 |
| 1076 | Cxy Energy, Inc. | Dallas, TX 75251 | Oil & Gas Operator | Nov 2000 |
| 1077 | Cygnus Producing Corporation | | Oil & Gas Operator | Feb 1990 |
| 1078 | Cymri Corporation, The | Houston, TX 77057 | Oil & Gas Operator | Mar 2008 |
| 1079 | Cypress E & P Corporation | Leander, TX 78646 | Oil & Gas Operator | Sep 2016 |
| 1080 | Cypress Gas Pipeline Company | | Oil Operator | Dec 1998 |
| 1081 | Cypress Gas Pipeline, LLC | | Oil Operator | Sep 2019 |
| 1082 | Cypress Oil Company, Inc. | | Oil & Gas Operator | Aug 2003 |
| 1083 | Cypress Operating, Inc. | Shreveport, LA 71101 | Oil & Gas Operator | Feb 2026 |
| 1084 | Cypress Partners, Inc. | Houston, TX 77068 | Oil & Gas Operator | May 1999 |
| 1085 | Cypress Production, Inc. | Azle, TX 76020 | Oil & Gas Operator | Feb 2026 |
| 1086 | Cypress Resources | | Oil & Gas Operator | Jul 2004 |
| 1087 | Czar Resources Inc | Houston, TX 77060 | Oil & Gas Operator | Oct 1992 |
| 1088 | D & C Operating, Inc. | | Oil & Gas Operator | Apr 1999 |
| 1089 | D & D DRLG Co & Saye Oil Co | | Oil Operator | Apr 1982 |
| 1090 | D & D Expl Co-Mba Energy | | Oil Operator | Nov 1985 |
| 1091 | D & D Exploration Co. | | Oil & Gas Operator | Nov 1986 |
| 1092 | D & D Oil Company | Dayton, TX 77535 | Oil & Gas Operator | Feb 2026 |
| 1093 | D & G Energy Corporation | Houston, TX 77056 | Oil & Gas Operator | Dec 1995 |
| 1094 | D & J Producing Company | | Oil Operator | Sep 2006 |
| 1095 | D & L Partnership | Rhome, TX 76078 | Oil Operator | May 1987 |
| 1096 | D & T Company | | Oil & Gas Operator | Jun 1983 |
| 1097 | D & V Petroleum Corporation | | Oil & Gas Operator | May 1992 |
| 1098 | D & W Oil & Gas Co. | | Gas Operator | Jan 1990 |
| 1099 | D C Bintliff & W W F Oil Corp. | | Oil & Gas Operator | Dec 1989 |
| 1100 | D H & L Operating, Inc. | | Oil & Gas Operator | Sep 1983 |