| 101 | C And D Explorations LLC | | Oil Operator | Dec 2025 |
| 102 | C And M Oil Inc | Kimball, NE 69145 | Oil & Gas Operator | Dec 2024 |
| 103 | C And S Oil & Gas | San Antonio, TX 78217 | Oil & Gas Operator | Feb 1998 |
| 104 | C Bar K Enterprises Inc | Oklahoma City, OK 73154-1828 | Oil & Gas Operator | Dec 2022 |
| 105 | C Bar Petroleum Company | Lubbock, TX 79413 | Oil & Gas Operator | May 2018 |
| 106 | C C & S Oil Oper | | Oil Operator | Apr 1983 |
| 107 | C C Co | Holladay, UT 84124 | Oil & Gas Operator | Jan 2020 |
| 108 | C D Oil | Wellsville, KS 66092 | Oil Operator | Aug 1998 |
| 109 | C D Operating Company Inc | Oklahoma City, OK 73116 | Oil & Gas Operator | Apr 2015 |
| 110 | C E D LC | Enid, OK 73702-0326 | Oil & Gas Operator | Oct 2021 |
| 111 | C E Energy LLC | Katy, TX 77449 | Oil Operator | Dec 2025 |
| 112 | C E Harmon Oil Inc | Tulsa, OK 74136-6559 | Oil & Gas Operator | Nov 2025 |
| 113 | C E L Inc | Bartlesville, OK 74006 | Oil & Gas Operator | Jan 2020 |
| 114 | C E Larue & B M Muncy Jr | Artesia, NM 882111370 | Oil & Gas Operator | Jun 2006 |
| 115 | C E Long | Midland, TX 79702 | Oil & Gas Operator | Apr 1994 |
| 116 | C E Staples | Dallas, TX 75205 | Oil & Gas Operator | Jul 1995 |
| 117 | C F & L Producing Co | | Oil & Gas Operator | Sep 2000 |
| 118 | C F M Oil Co Dba Louis And Judy Fulton | Artesia, NM 88210 | Oil & Gas Operator | May 2011 |
| 119 | C F Oil - Frazie | | Oil Operator | Dec 1994 |
| 120 | C G Davis, Et Al | | Oil & Gas Operator | Mar 1986 |
| 121 | C G G Oil Co | | Oil & Gas Operator | Dec 2006 |
| 122 | C G O Inc | Wheeling, WV 26003 | Oil & Gas Operator | Dec 2024 |
| 123 | C G Oil, Inc. | Victoria, KS 67671 | Oil Operator | Sep 2025 |
| 124 | C H E Company Inc | Shawnee, OK 74801 | Oil Operator | Feb 2012 |
| 125 | C H K Oil, LLC | Stephens, AR 71764 | Oil Operator | Jan 2025 |
| 126 | C K Oil Company | Great Bend, KS 67530 | Oil & Gas Operator | Sep 2025 |
| 127 | C L & S Oil Company Inc | Perry, OK 73077-0841 | Oil & Gas Operator | Jan 2018 |
| 128 | C L Conner | Humble, TX 77338 | Oil & Gas Operator | Oct 2025 |
| 129 | C M F Oil LLC | | Oil Operator | Dec 2024 |
| 130 | C M S Gas Transmission Co | | Oil & Gas Operator | Dec 2020 |
| 131 | C M S Oil And Gas Co And Miller Brothers | | Oil & Gas Operator | Apr 1992 |
| 132 | C M T Petroleum | | Oil Operator | Jul 1995 |
| 133 | C M X Incorporat | | Oil & Gas Operator | Dec 1996 |
| 134 | C N B Enterprises | Yates Center, KS 66783 | Oil & Gas Operator | Jan 2009 |
| 135 | C N Operating Co | Drumright, OK 74030 | Oil & Gas Operator | Nov 1998 |
| 136 | C O Fulton | Artesia, NM 88211 | Oil & Gas Operator | Sep 2022 |
| 137 | C O G Company | Bangs, TX 76823 | Oil & Gas Operator | Dec 2025 |
| 138 | C Oil Co. | New Braunfels, TX 78132 | Oil & Gas Operator | Feb 2017 |
| 139 | C R A C O Incorp | | Oil Operator | May 1988 |
| 140 | C R I Inc | Midland, TX 79702 | Oil & Gas Operator | Nov 1993 |
| 141 | C Rose Oil Co. | Midland, TX 79708 | Oil & Gas Operator | Oct 2025 |
| 142 | C S J, Inc. | Austin, TX 78716 | Oil & Gas Operator | Dec 2025 |
| 143 | C T R Resources Inc | Alliance, OH 44601 | Oil & Gas Operator | Dec 2013 |
| 144 | C W Oil Producer | | Oil Operator | Oct 1998 |
| 145 | C W Riggs Inc | St. Marys, WV 26170 | Oil & Gas Operator | Dec 1999 |
| 146 | C W Trainer | Midland, TX 79702 | Oil & Gas Operator | Nov 2009 |
| 147 | C&C II | Pleasanton, TX 78064 | Oil & Gas Operator | Mar 1998 |
| 148 | C&D Management Company Dba Freedom Ventures | Las Vegas, NV 89149 | Oil & Gas Operator | Feb 2019 |
| 149 | C&M Operating Company, LLC | | Oil & Gas Operator | Apr 2011 |
| 150 | C&P Resources Operating Co,LLC | Houston, TX 77056 | Oil & Gas Operator | Dec 2025 |
| 151 | C-D Oil Company, Inc. | Cameron, TX 76520 | Oil Operator | Dec 2025 |
| 152 | C-V Oil Company | Memphis, TN 38103 | Oil Operator | Jun 1998 |
| 153 | C-Water Disposal Inc | Oklahoma City, OK 73116-7326 | Oil Operator | Dec 2014 |
| 154 | C. A. Cardneaux, Inc. | | Oil & Gas Operator | Apr 1990 |
| 155 | C. C. Killingsworth Opr. | | Oil Operator | Dec 1999 |
| 156 | C. Case Company | | Oil & Gas Operator | Oct 2025 |
| 157 | C. D. Oil, Inc. | Wellsville, KS 66092 | Oil Operator | Dec 2009 |
| 158 | C. D. Pierce | | Oil Operator | Mar 1991 |
| 159 | C. E. Allen Co. Inc. | | Oil & Gas Operator | Nov 2025 |
| 160 | C. E. Braly | | Oil & Gas Operator | Dec 1991 |
| 161 | C. F. Oil, A General Partnership | Lake Lotawana, MO 64086 | Oil Operator | Sep 2025 |
| 162 | C. F. Sudduth | | Oil & Gas Operator | Dec 1988 |
| 163 | C. H. C. Gerard | | Oil & Gas Operator | Jan 2025 |
| 164 | C. H. Cuatro | | Gas Operator | Sep 1996 |
| 165 | C. H. Todd, Inc. | Wichita, KS 67212 | Oil & Gas Operator | Dec 2019 |
| 166 | C. I. McKown & Son, Inc. | Newton, WV 25266-0711 | Oil & Gas Operator | Dec 2021 |
| 167 | C. J. Broome Oil Company | | Oil & Gas Operator | Jan 2020 |
| 168 | C. J. Filson, LLC | Protection, KS 67127 | Gas Operator | Aug 2014 |
| 169 | C. J. Services | | Oil & Gas Operator | Sep 2016 |
| 170 | C. L. Brown, III | | Oil Operator | Dec 1991 |
| 171 | C. L. Brown, Inc. | | Oil Operator | Dec 1999 |
| 172 | C. L. Morris | | Oil Operator | Feb 2004 |
| 173 | C. L. Morris, Inc. | | Oil & Gas Operator | Feb 2004 |
| 174 | C. M. Frizzell | | Oil & Gas Operator | Mar 2014 |
| 175 | C. M. Oil Corporation | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Mar 2016 |
| 176 | C. M. Roberson | | Oil Operator | Jun 1984 |
| 177 | C. O. Oil And Gas, LLC | Pampa, TX 79066 | Oil & Gas Operator | Dec 2025 |
| 178 | C. Smith & Associates, Inc. | | Oil Operator | Aug 1991 |
| 179 | C. T. & Ted Paul | | Oil Operator | Mar 2019 |
| 180 | C. V. Radke | | Oil Operator | Jan 1993 |
| 181 | C. W. Brumley | | Oil & Gas Operator | Jun 2006 |
| 182 | C. W. Resources, Inc. | Longview, TX 75604 | Oil & Gas Operator | Oct 2025 |
| 183 | C. Wayland Brooks | | Oil & Gas Operator | Dec 1987 |
| 184 | C.B.C. Producing Co. | | Oil & Gas Operator | Jul 1989 |
| 185 | C.C.O. & G. Company Inc. | Austin, TX 78765 | Oil & Gas Operator | Sep 1995 |
| 186 | C.F. Braun & Company | | Oil & Gas Operator | Dec 1986 |
| 187 | C.F.D. Inc. | | Oil & Gas Operator | Nov 1988 |
| 188 | C.F.O., Inc. | Liberty, TX 77575 | Oil Operator | Dec 2025 |
| 189 | C.J. Oil Company | Iowa Park, TX 76367 | Oil Operator | Jan 2025 |
| 190 | C.O.W. Operating Company | Graham, TX 76450 | Oil Operator | Dec 2025 |
| 191 | C.P.I. | | Oil & Gas Operator | Oct 2007 |
| 192 | C.S.V. Oil Exploration Co | West Jordan, UT 84088 | Gas Operator | Nov 2025 |
| 193 | C.T.R. Oil, Inc. | | Oil & Gas Operator | Jan 2025 |
| 194 | C.W. Pickering, Inc. | Victoria, TX 77904 | Gas Operator | Sep 2022 |
| 195 | C.W.F.K., Inc. | | Gas Operator | Dec 1986 |
| 196 | C12 Energy: North Dakota LLC | | Oil Operator | Apr 2017 |
| 197 | C12 Kansas Oil, LLC | Denver, CO 80202 | Oil Operator | Dec 2009 |
| 198 | C3oil, LLC | New Strawn, KS 66839 | Oil Operator | Sep 2025 |
| 199 | C5 Energy LLC | Collinsville, OK 74021 | Oil & Gas Operator | Dec 2019 |
| 200 | C6 Operating, L.L.C. | Keatchie, LA 71046 | Oil & Gas Operator | Dec 2025 |