| 1001 | Century Well Service | Cumberland, WV 26047 | Oil & Gas Operator | Dec 2006 |
| 1002 | Ceo Operating, Co. | | Oil & Gas Operator | Dec 1999 |
| 1003 | Cep Mid-Continent LLC | Skiatook, OK 74070 | Oil & Gas Operator | Feb 2025 |
| 1004 | Cerberus Engineering, LLC | San Antonio, TX 78209 | Oil & Gas Operator | Jun 2025 |
| 1005 | Cerro Oil Co., Inc. | | Oil Operator | Dec 1987 |
| 1006 | Certified Petroleum Inc. | Mineral Wells, TX 76067 | Oil & Gas Operator | May 2006 |
| 1007 | Cesinger Exploration Service, In | Dallas, TX 75208 | Oil & Gas Operator | Mar 2006 |
| 1008 | Cet Energy Corporation | Spring, TX 77391 | Oil & Gas Operator | Nov 2003 |
| 1009 | Cewell Energy LLC | Houston, TX 77042 | Oil & Gas Operator | Jul 2024 |
| 1010 | Cex Operating Company | Dallas, TX 75206 | Oil & Gas Operator | Mar 2008 |
| 1011 | CFC Oil Inc | Cyril, OK 73029-5601 | Oil & Gas Operator | Mar 2025 |
| 1012 | CFG Energy, Inc | | Oil & Gas Operator | Apr 2006 |
| 1013 | CFM 66 LLC | McPherson, KS 67460 | Oil & Gas Operator | Dec 2024 |
| 1014 | CFM Oil, LLC | Artesia, NM 88210 | Oil & Gas Operator | Mar 2025 |
| 1015 | Cfo Resources, Inc. | Corpus Chrsti, TX 78412 | Oil & Gas Operator | Jun 2025 |
| 1016 | CFT Oil & Gas LLC | | Oil Operator | Apr 2025 |
| 1017 | CG Oil Co. | San Antonio, TX 78232 | Oil & Gas Operator | Mar 2011 |
| 1018 | CG Operating, Inc. | Austin, TX 78759 | Oil & Gas Operator | Jun 2025 |
| 1019 | CG Technical Operating Co, LLC | Stamford, TX 79553 | Oil Operator | Jun 2025 |
| 1020 | CG&G Oil LLC | New Matamoras, OH 45767 | Oil & Gas Operator | Dec 2021 |
| 1021 | Cgas Expl Inc | Columbus, OH 43214-1862 | Oil & Gas Operator | Dec 2006 |
| 1022 | Cgas Exploration | Charleston, WV 25301 | Oil & Gas Operator | Dec 2006 |
| 1023 | CGS Operating, LLC | Kilgore, TX 75663 | Oil & Gas Operator | May 2023 |
| 1024 | CGT Inc | | Oil & Gas Operator | May 2015 |
| 1025 | CH-Seon Inc. | Dallas, TX 75251 | Oil & Gas Operator | Jun 2025 |
| 1026 | CH4 Energy II LLC | Fort Worth, TX 76109 | Oil & Gas Operator | Apr 2018 |
| 1027 | CH4 Energy LLC | Fort Worth, TX 76102 | Oil & Gas Operator | May 2006 |
| 1028 | CH4 Energy Six, LLC | Fort Worth, TX 76107 | Oil & Gas Operator | Jun 2025 |
| 1029 | CH4 Production Company Inc | Tulsa, OK 74170-1955 | Gas Operator | May 2007 |
| 1030 | Chace Oil Co Inc | Dallas, TX 75229 | Oil & Gas Operator | Mar 2006 |
| 1031 | Chaco Energy Company | Denver, CO 80201 | Oil & Gas Operator | Apr 2025 |
| 1032 | Chadco, Inc. | | Oil Operator | Dec 2024 |
| 1033 | Chaim Nathan & Edie Bato | | Oil & Gas Operator | Apr 2025 |
| 1034 | Chain Oil & Gas, Inc. | Houston, TX 77024 | Oil & Gas Operator | Jun 2025 |
| 1035 | Chalice Petroleum Corporation | Dallas, TX 75202 | Oil & Gas Operator | May 1998 |
| 1036 | Chalk, Otis, Estate | Big Spring, TX 79721 | Oil & Gas Operator | Jan 2006 |
| 1037 | Chalker Energy Management II,LLC | Houston, TX 77002 | Oil & Gas Operator | Feb 2008 |
| 1038 | Chalker Energy Management,LLC | Houston, TX 77002 | Oil & Gas Operator | Dec 2006 |
| 1039 | Chalker Operating Inc. | Richmond, TX 77406 | Oil & Gas Operator | Jul 2016 |
| 1040 | Challenge Operating Inc | Tulsa, OK 74103 | Oil & Gas Operator | Feb 2024 |
| 1041 | Challenger Energy SVCS Co., LLC | Kilgore, TX 75663 | Oil Operator | Jun 2025 |
| 1042 | Challenger Exploration | | Oil Operator | Nov 2014 |
| 1043 | Challenger Minerals Inc. | | Oil & Gas Operator | Dec 1991 |
| 1044 | Challenger Point Energy, LLC | | Oil & Gas Operator | Apr 2025 |
| 1045 | Chalmers Exploration Company | Abilene, TX 79608 | Oil & Gas Operator | Apr 1997 |
| 1046 | Chalmers-Santa Fe LLC | | Oil & Gas Operator | Dec 2007 |
| 1047 | Chama Resources | Dallas, TX 75354 | Oil & Gas Operator | Apr 2009 |
| 1048 | Chamberlain Dba/Old South Oil | Marietta, OH 45750 | Oil & Gas Operator | Dec 2008 |
| 1049 | Chambers & Hendrix Oil & Gas | Skiatook, OK 74070-0726 | Oil & Gas Operator | Aug 2022 |
| 1050 | Chambers & Mouren | | Oil & Gas Operator | Apr 2025 |
| 1051 | Chambers Exploration Inc. | | Oil & Gas Operator | Dec 1986 |
| 1052 | Chambers Jerry | Denver, CO 80237 | Oil & Gas Operator | Dec 1993 |
| 1053 | Chambers Jerry Expl Co | | Oil & Gas Operator | Sep 2000 |
| 1054 | Chambers Operating, Inc. | Westbrook, TX 79565 | Oil & Gas Operator | Mar 2006 |
| 1055 | Chambers, R. H. | Abilene, TX 79606 | Oil & Gas Operator | Apr 2006 |
| 1056 | Chambers, R. H. LLC | Abilene, TX 79606 | Oil & Gas Operator | Jun 2025 |
| 1057 | Champ Oil Co, Inc | Hickory Creek, TX 75065 | Oil & Gas Operator | Dec 2020 |
| 1058 | Champ Operating Company | Dallas, TX 75208 | Oil & Gas Operator | Oct 2020 |
| 1059 | Champion Lone Star Operating,LLC | Midland, TX 79702 | Oil & Gas Operator | Mar 2020 |
| 1060 | Champion Petrole | | Oil Operator | Jan 1992 |
| 1061 | Champion Reserves-Cri Inc | Oklahoma City, OK 73123 | Oil & Gas Operator | Jun 1994 |
| 1062 | Champion-Park Gas Corporation | Warren, OH 44483 | Oil & Gas Operator | Dec 2023 |
| 1063 | Champlin Exploration, Inc. | Enid, OK 73702 | Oil & Gas Operator | Mar 2025 |
| 1064 | Champlin Petroleum Co. | Rock Springs, WY 82902 | Oil & Gas Operator | Mar 1991 |
| 1065 | Champlin SR., Bryan | Kennedy, NY 14747 | Gas Operator | Dec 2023 |
| 1066 | Chan West Oil Corporation | Irving, TX 75016 | Oil & Gas Operator | Jun 2025 |
| 1067 | Chanc West, Inc. | Iraan, TX 79744 | Oil & Gas Operator | Mar 1995 |
| 1068 | Chance Drilling Company | Commerce City, CO 80022 | Oil Operator | Sep 2009 |
| 1069 | Chance Energy Co. Inc. | Amarillo, TX 79114 | Oil & Gas Operator | Sep 1999 |
| 1070 | Chance Oil Co., Inc. | Vernon, TX 76385 | Oil & Gas Operator | Mar 2025 |
| 1071 | Chance Properties Co. | Kermit, TX 79745 | Oil & Gas Operator | Jun 2025 |
| 1072 | Chancellor & Dolezal | | Gas Operator | Apr 1992 |
| 1073 | Chancellor, Earl Sales Co., Inc. | Sweetwater, TX 79556 | Oil & Gas Operator | Jun 2025 |
| 1074 | Chandler & Associated Inc | Denver, CO 80202 | Oil & Gas Operator | Dec 1999 |
| 1075 | Chandler & Associates LLC | | Oil & Gas Operator | Jul 2001 |
| 1076 | Chandler & Associates, Inc. | Denver, CO 80202 | Oil & Gas Operator | May 1997 |
| 1077 | Chandler DJ Basin LLC | | Oil & Gas Operator | Jul 2012 |
| 1078 | Chandler Energy LLC | Denver, CO 80202 | Oil & Gas Operator | Jan 2009 |
| 1079 | Chandler Oil & Gas, LLC | Beeville, TX 78102 | Oil & Gas Operator | Jun 2025 |
| 1080 | Chaney & Cogburn Roustabout Well Serv | Cement, OK 73017-0267 | Oil & Gas Operator | Mar 2015 |
| 1081 | Chaney Oil Company | Andrews, TX 79714 | Oil & Gas Operator | Jun 2025 |
| 1082 | Chaney, Jerry C. And Jean R. | Chester, WV 26034-0000 | Gas Operator | Dec 2021 |
| 1083 | Channa Operating, LLC | Houston, TX 77063 | Oil & Gas Operator | Jul 2021 |
| 1084 | Channel Exploration Company | | Oil & Gas Operator | Feb 1997 |
| 1085 | Channel Production Company | Marshall, TX 75670 | Oil & Gas Operator | Jun 2025 |
| 1086 | Chanse Energy Corporation | Shreveport, LA 71165-1572 | Oil & Gas Operator | Sep 2021 |
| 1087 | Chanse Petroleum Corporation | New York, NY 10165-1134 | Oil & Gas Operator | Feb 2015 |
| 1088 | Chantrey Corporation | Midland, TX 79707 | Gas Operator | Feb 2003 |
| 1089 | Chanze Oil Co., Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Jun 2025 |
| 1090 | Chap Operating, Inc. | Knox City, TX 79529 | Oil & Gas Operator | Jun 2025 |
| 1091 | Chaparosa Production Company,Inc | Freer, TX 78357 | Oil & Gas Operator | Jun 2025 |
| 1092 | Chaparral (USA) Energy, Inc. | Oklahoma City, OK 73114 | Oil & Gas Operator | Sep 2002 |
| 1093 | Chaparral Energy, Inc. | Oklahoma City, OK 73114 | Oil & Gas Operator | Dec 2009 |
| 1094 | Chaparral Energy, L.L.C. | Oklahoma City, OK 73142 | Oil & Gas Operator | Jun 2025 |
| 1095 | Chaparral Expl & C L Morris In | | Oil & Gas Operator | Nov 1994 |
| 1096 | Chaparral Exploration, Inc. | | Oil & Gas Operator | Jun 2000 |
| 1097 | Chaparral Natural Resources,Inc. | Austin, TX 78746 | Oil & Gas Operator | Jun 2025 |
| 1098 | Chaparral Oil & Gas Co | Aztec, NM 87410 | Gas Operator | Mar 2025 |
| 1099 | Chaparral Operating, Inc. | Shreveport, LA 71166 | Oil & Gas Operator | Jun 2025 |
| 1100 | Chaparral Petroleum Inc. | | Oil Operator | Mar 2025 |