| 1 | C & A Oil Company | Edmond, OK 73013-9413 | Oil & Gas Operator | Mar 2015 |
| 2 | C E D LC | Enid, OK 73702-0326 | Oil & Gas Operator | Oct 2021 |
| 3 | C L & S Oil Company Inc | Perry, OK 73077-0841 | Oil & Gas Operator | Jan 2018 |
| 4 | C-Water Disposal Inc | Oklahoma City, OK 73116-7326 | Oil Operator | Dec 2014 |
| 5 | C.D. Operating Company, Inc. | Oklahoma City, OK 73116 | Oil & Gas Operator | Apr 2015 |
| 6 | Cabot Oil & Gas Corporation | Houston, TX 77024 | Oil & Gas Operator | Apr 2025 |
| 7 | Cactus Energy Company LLC | Hennessey, OK 73742 | Oil & Gas Operator | Apr 2025 |
| 8 | Cain Richard | Comanche, OK 73529-1248 | Oil & Gas Operator | May 2020 |
| 9 | Canaan Exploration Inc | Oklahoma City, OK 73123 | Oil & Gas Operator | Jan 1998 |
| 10 | Canok International Inc | Okmulgee, OK 74447 | Oil & Gas Operator | May 2025 |
| 11 | Canvas Energy LLC | Oklahoma City, OK 73142-1839 | Oil & Gas Operator | May 2025 |
| 12 | Carl E Gungoll Exploration LLC | Oklahoma City, OK 73154 | Oil & Gas Operator | May 2025 |
| 13 | Carl Humphries Inc | Piedmont, OK 73078-0514 | Oil & Gas Operator | May 2025 |
| 14 | Case Sales Company Inc | Tonkawa, OK 74653-0040 | Oil & Gas Operator | Apr 2025 |
| 15 | Ceja Corporation | Tulsa, OK 74172 | Oil & Gas Operator | Apr 2025 |
| 16 | Centaur Resources Inc | Oklahoma City, OK 73142-6804 | Oil & Gas Operator | Apr 2025 |
| 17 | Centrex Operating Company | Tulsa, OK 74105 | Oil & Gas Operator | Apr 2025 |
| 18 | Cep Mid-Continent LLC | Skiatook, OK 74070 | Oil & Gas Operator | Apr 2025 |
| 19 | Chaco Energy Company | Denver, CO 80201 | Oil & Gas Operator | May 2025 |
| 20 | Charter Oak Production Co LLC | Oklahoma City, OK 73134 | Oil & Gas Operator | Jul 2025 |
| 21 | Cherokee Operating Company | Tulsa, OK 74103 | Oil & Gas Operator | Mar 2015 |
| 22 | Chesapeake Operating LLC | Oklahoma City, OK 73154 | Oil & Gas Operator | Jul 2025 |
| 23 | Chevron USA Inc | Midland, TX 79706 | Oil & Gas Operator | Jul 2025 |
| 24 | Chizum Oil LLC | Wichita, KS 67211 | Oil & Gas Operator | Apr 2025 |
| 25 | Choate Kenny Dba Rebound Oil Co | Helena, OK 73741-0543 | Gas Operator | May 2025 |
| 26 | Christa Oil Co | Cumberland, OH 43732 | Oil & Gas Operator | Nov 1999 |
| 27 | Cimarron Oil & Gas Inc | Perry, OK 73077-1318 | Oil & Gas Operator | Sep 2000 |
| 28 | Cisco Operating LLC | Plano, TX 75024 | Oil & Gas Operator | Mar 2025 |
| 29 | Citation Oil & Gas Corp. | Houston, TX 77269 | Oil & Gas Operator | Jul 2025 |
| 30 | Claremont Corporation | Tulsa, OK 74119 | Oil & Gas Operator | Feb 2017 |
| 31 | Clifton & Associates Inc | Tulsa, OK 74133 | Oil & Gas Operator | May 2020 |
| 32 | Co-St Oil Operating Co Inc | Enid, OK 73706 | Oil & Gas Operator | Apr 1997 |
| 33 | Columbia Production Company | Edmond, OK 73083 | Oil & Gas Operator | May 2020 |
| 34 | Combined Resources Corporation | Edmond, OK 73083 | Oil & Gas Operator | Jul 2025 |
| 35 | Concho Exploration Inc | Oklahoma City, OK 73154 | Oil & Gas Operator | Mar 2015 |
| 36 | Conoco Inc. | Houston, TX 77252 | Oil & Gas Operator | Mar 2015 |
| 37 | ConocoPhillips Company | Midland, TX 79701 | Oil & Gas Operator | Jul 2025 |
| 38 | Consolidated Oil & Gas Inc | Wichita, KS 67202 | Oil & Gas Operator | Dec 2012 |
| 39 | Contango Resources LLC | Andrews, TX 79714 | Oil & Gas Operator | Jul 2025 |
| 40 | Continental Operating Co. | Houston, TX 77024 | Oil & Gas Operator | Jul 2025 |
| 41 | Continental Resources, Inc. | Oklahoma City, OK 73126 | Oil & Gas Operator | Jul 2025 |
| 42 | Convest Energy Corporation | Houston, TX 77057 | Oil & Gas Operator | Sep 2014 |
| 43 | Cooper Operating LLC | Oklahoma City, OK 73134 | Oil & Gas Operator | Apr 2025 |
| 44 | Cornelius Petroleum Inc | | Oil & Gas Operator | May 2025 |
| 45 | Coronado Petroleum Corporation | Oklahoma City, OK 73102-4803 | Oil & Gas Operator | Apr 2025 |
| 46 | Covington Oil Company Inc | Nichols Hills, OK 73116 | Oil & Gas Operator | May 2025 |
| 47 | Cow Creek Resources Inc | Ponca City, OK 74601-7815 | Oil & Gas Operator | Apr 2025 |
| 48 | Crain & Deisenroth | Tulsa, OK 74103-4433 | Oil & Gas Operator | Mar 2015 |
| 49 | Crain & Deisenroth LLC | Tulsa, OK 74104-6511 | Oil & Gas Operator | Apr 2014 |
| 50 | Crain Minerals LLC | Oklahoma City, OK 73120-1004 | Oil & Gas Operator | Aug 2014 |
| 51 | Crawley Petroleum Corporation | Oklahoma City, OK 73102 | Oil & Gas Operator | Jul 2025 |
| 52 | Cromer Carroll Oil & Gas LLC | Kalispell, MT 59901 | Oil & Gas Operator | Apr 2025 |
| 53 | Cross Timbers Operating Co | Fort Worth, TX 76102 | Oil & Gas Operator | Mar 2025 |
| 54 | Cross Timbers Production Co | Oklahoma City, OK 73102-5605 | Oil & Gas Operator | Mar 2005 |
| 55 | Cross, Don E | | Oil & Gas Operator | Jan 2013 |
| 56 | Crow Creek Operating Co III LLC | Tulsa, OK 74137-8432 | Oil & Gas Operator | Apr 2015 |
| 57 | Crown Energy Company | Oklahoma City, OK 73106 | Oil & Gas Operator | Apr 2025 |
| 58 | Crusader Energy Corporation | Oklahoma City, OK 73102 | Oil & Gas Operator | Sep 2011 |
| 59 | Crystal Energy Inc | Oklahoma City, OK 73116 | Oil & Gas Operator | Feb 2019 |
| 60 | Culp & Copple Oil Company | Cushing, OK 74023 | Oil & Gas Operator | Feb 2025 |
| 61 | Curran Oil Co | Great Falls, MT 59401 | Gas Operator | May 2001 |