| 1 | Caledonia Energy Partners, LLC | | Oil & Gas Operator | Mar 2007 |
| 2 | Callon Oil Co, Cambell | | Oil & Gas Operator | Oct 1984 |
| 3 | Callon Petroleum Company | Natchez, MS 39120 | Oil & Gas Operator | Jan 2000 |
| 4 | Calto Operating Company, Inc. | Dallas, TX 75225 | Oil & Gas Operator | May 2004 |
| 5 | Campbell Co. Et Al | | Oil Operator | Apr 1986 |
| 6 | Cardneaux Inc | | Oil & Gas Operator | Aug 2009 |
| 7 | Carl E Gungoll Exploration LLC | Oklahoma City, OK 73154 | Oil & Gas Operator | Aug 2025 |
| 8 | Castor Exploration, Inc. | | Oil & Gas Operator | Dec 1991 |
| 9 | Cavalier Oil Co. Et Al | | Oil Operator | Jan 1986 |
| 10 | Cavins Oilfield Services, LLC. | | Oil Operator | Apr 2006 |
| 11 | CCM Enterprises, Inc | | Oil & Gas Operator | Oct 1985 |
| 12 | Cedar Grove Energy Corp. | | Oil Operator | Sep 2009 |
| 13 | Centerpoint Water Disposal Inc | | Oil & Gas Operator | Aug 1984 |
| 14 | Central Operating, LLC | | Oil & Gas Operator | Aug 2025 |
| 15 | Centurion Resources LLC | Tulsa, OK 74136 | Oil & Gas Operator | Mar 2015 |
| 16 | Century Exploration New Orleans, LLC | | Oil & Gas Operator | Mar 2008 |
| 17 | Ceo Operating, Co. | | Oil & Gas Operator | Dec 1999 |
| 18 | Chase Oil & Gas Inc C-O Triad | | Oil & Gas Operator | Mar 1993 |
| 19 | Chevron U. S. A., Inc. -Ca | | Oil & Gas Operator | Jan 2000 |
| 20 | Chevron U. S. A., Inc. -TX | | Oil & Gas Operator | Dec 2004 |
| 21 | Cheyenne Minerals, Inc. | Houston, TX 77030 | Oil & Gas Operator | Jun 2001 |
| 22 | Christian Well Service | | Oil & Gas Operator | May 1987 |
| 23 | Cimarex Energy Co | Midland, TX 79706 | Oil & Gas Operator | Nov 2025 |
| 24 | Citation Oil & Gas Corp | Houston, TX 77269 | Oil & Gas Operator | Nov 2025 |
| 25 | Cities Service Oil Co. | | Oil & Gas Operator | Dec 1986 |
| 26 | Clark, Donald-Roger Young | | Oil & Gas Operator | Jan 1988 |
| 27 | Clark, Noel D. Et Al | | Oil & Gas Operator | Mar 1994 |
| 28 | Clarkco Services, Inc. | | Oil & Gas Operator | Aug 2025 |
| 29 | Clayton Williams Energy, Inc. | Houston, TX 77070 | Oil & Gas Operator | Apr 2017 |
| 30 | Cleveland Production Company | Summit, MS 39666 | Oil & Gas Operator | Jul 1999 |
| 31 | Clinch Drilling Company | | Oil & Gas Operator | Jan 2000 |
| 32 | CMW Oil Company | | Oil & Gas Operator | Dec 1976 |
| 33 | Cobra Oil & Gas Corporation | Wichita Falls, TX 76307 | Oil & Gas Operator | Nov 2025 |
| 34 | Cody Operating, Inc. | | Oil & Gas Operator | Aug 2025 |
| 35 | Coho Resources Inc. | Dallas, TX 75240 | Oil & Gas Operator | Jul 2002 |
| 36 | Collins Associates Inc | | Oil & Gas Operator | Mar 1987 |
| 37 | Colt Energy Inc | Iola, KS 66749 | Oil & Gas Operator | Jun 2025 |
| 38 | Columbia Petroleum LLC | Oyster Bay, NY 11771 | Oil & Gas Operator | Feb 2025 |
| 39 | Comstock Oil & Gas, LP | Frisco, TX 75034 | Oil & Gas Operator | Aug 2019 |
| 40 | Conquest Exploration Co. | | Oil & Gas Operator | Mar 1992 |
| 41 | Consolidated Engy Reserve Inc | | Oil & Gas Operator | Jul 1991 |
| 42 | Continental Oil Co. | Durango, CO 81301 | Oil & Gas Operator | Dec 1983 |
| 43 | Cornwell Well Service, Inc. | | Oil & Gas Operator | Feb 2010 |
| 44 | Cornwell, G. G. | | Oil & Gas Operator | Sep 2009 |
| 45 | Craft Petroleum Company, Inc. Et Al | | Oil & Gas Operator | Mar 1997 |
| 46 | Crain & Dore' | | Oil & Gas Operator | May 1986 |
| 47 | Crook-Woodlin Expl.,Inc. | | Oil Operator | Feb 1988 |
| 48 | Crystal Oil Company | Shreveport, LA 71120 | Oil & Gas Operator | Jul 1995 |
| 49 | CWF Associates, LTD. | | Oil & Gas Operator | Apr 1988 |