| 1 | C & R Petroleum Co. | Duncan, OK 73533-1341 | Oil & Gas Operator | Feb 2025 |
| 2 | C.D. Operating Company, Inc. | Oklahoma City, OK 73116 | Oil & Gas Operator | Apr 2015 |
| 3 | Canaan Energy Corporation | Oklahoma City, OK 73154-8806 | Oil & Gas Operator | Mar 2015 |
| 4 | Canvas Energy LLC | Oklahoma City, OK 73142-1839 | Oil & Gas Operator | Mar 2025 |
| 5 | Carlson Petroleum Company | Houston, TX 77010 | Oil & Gas Operator | Mar 2015 |
| 6 | Cemoil Inc | Cement, OK 73017-0563 | Oil & Gas Operator | Mar 2025 |
| 7 | Chaco Energy Company | Denver, CO 80201 | Oil & Gas Operator | Apr 2025 |
| 8 | Chesapeake Operating LLC | Oklahoma City, OK 73154 | Oil & Gas Operator | Jun 2025 |
| 9 | Cheyenne Petroleum Company | Oklahoma City, OK 73134 | Oil & Gas Operator | Jun 2025 |
| 10 | Cibola Energy Corporation | Albuquerque, NM 87103 | Oil & Gas Operator | Oct 2017 |
| 11 | Clark And Clark | Princeton, NJ 08540-1930 | Oil & Gas Operator | Jul 2013 |
| 12 | Clift Cary E | Chickasha, OK 73018-6305 | Oil & Gas Operator | Sep 2024 |
| 13 | Coho Oil & Gas Inc | Coppell, TX 75019-8288 | Oil & Gas Operator | Mar 2015 |
| 14 | Columbia Production Company | Edmond, OK 73083 | Oil & Gas Operator | May 2020 |
| 15 | Comanche Exploration Co LLC | Oklahoma City, OK 73116-7334 | Oil & Gas Operator | Mar 2025 |
| 16 | Comanche Exploration Company | Oklahoma City, OK 73120-2797 | Oil & Gas Operator | Feb 2007 |
| 17 | Combined Resources Corporation | Edmond, OK 73083 | Oil & Gas Operator | Jun 2025 |
| 18 | Comet Oil Company | Velma, OK 73091 | Oil & Gas Operator | May 2005 |
| 19 | Comet-Haines Oil Company | Sulphur, OK 73086-0546 | Oil & Gas Operator | Mar 2013 |
| 20 | Compadre Drilling & Expl Corp | Ardmore, OK 73402 | Oil & Gas Operator | Mar 2015 |
| 21 | ConocoPhillips Company | Midland, TX 79701 | Oil & Gas Operator | Jun 2025 |
| 22 | Cook W R Inc | Duncan, OK 73534-0069 | Oil & Gas Operator | Jun 2000 |
| 23 | Couch Donald W | Marlow, OK 73055 | Oil & Gas Operator | Mar 2025 |
| 24 | Crawley Petroleum Corporation | Oklahoma City, OK 73102 | Oil & Gas Operator | Jun 2025 |
| 25 | Crown Petroleum Company | Duncan, OK 73534-0938 | Oil & Gas Operator | Jan 2011 |
| 26 | Crumpton H A | Duncan, OK 73533 | Oil Operator | Dec 2002 |