| 101 | Chapco, Inc. | Benavides, TX 78341 | Oil & Gas Operator | May 2025 |
| 102 | Chemily Management Company | Cypress, TX 77429 | Oil & Gas Operator | Apr 2023 |
| 103 | Chesapeake Operating LLC | Oklahoma City, OK 73154 | Oil & Gas Operator | May 2025 |
| 104 | Chesapeake Operating, Inc. | Oklahoma City, OK 73154 | Oil & Gas Operator | Jan 2025 |
| 105 | Chevron USA Inc | Midland, TX 79706 | Oil & Gas Operator | May 2025 |
| 106 | Chroma Operating, Inc. | Washington, DC 20036 | Oil & Gas Operator | Jun 2016 |
| 107 | Circle-S Energy, LLC | McKinney, TX 75071 | Oil & Gas Operator | May 2025 |
| 108 | Cliffwood Production Co. | Houston, TX 77090 | Oil & Gas Operator | Aug 2013 |
| 109 | Coalinga Corporation | Houston, TX 77002 | Oil & Gas Operator | May 1999 |
| 110 | Coastal Oil & Gas Corporation | Houston, TX 77252 | Oil & Gas Operator | Dec 2009 |
| 111 | Coastal Shoreline Corp. | Corpus Chrsti, TX 78460 | Oil & Gas Operator | Aug 2003 |
| 112 | Coates Energy Interests, LTD. | San Antonio, TX 78217 | Oil & Gas Operator | Aug 1997 |
| 113 | Cobbs Brothers Oil & Gas | Corpus Chrsti, TX 78476 | Oil & Gas Operator | Jun 2009 |
| 114 | Cobra Oil & Gas Corporation | Wichita Falls, TX 76307 | Oil & Gas Operator | May 2025 |
| 115 | Cobra Operating Company | Houston, TX 77002 | Oil & Gas Operator | Sep 2003 |
| 116 | Cody Energy LLC | Houston, TX 77024 | Oil & Gas Operator | Jun 2020 |
| 117 | Cody Energy, Inc. | Houston, TX 77077 | Oil & Gas Operator | Mar 2025 |
| 118 | Collins & Ware, Inc. | Midland, TX 79701 | Oil & Gas Operator | Aug 2003 |
| 119 | Columbus Energy Corp. | Tulsa, OK 74103 | Oil & Gas Operator | Mar 2008 |
| 120 | Columbus Energy, LLC | Houston, TX 77046 | Oil & Gas Operator | May 2025 |
| 121 | Cometra Oil And Gas, Inc. | Fort Worth, TX 76102 | Oil & Gas Operator | Feb 1997 |
| 122 | Comstock Oil & Gas, LLC | Frisco, TX 75034 | Oil & Gas Operator | May 2025 |
| 123 | Conoco Inc. | Houston, TX 77252 | Oil & Gas Operator | Mar 2015 |
| 124 | ConocoPhillips Company | Midland, TX 79701 | Oil & Gas Operator | May 2025 |
| 125 | Continental Exploration LLC | Lufkin, TX 75915 | Oil & Gas Operator | May 2025 |
| 126 | Continental Operating Co. | Houston, TX 77024 | Oil & Gas Operator | May 2025 |
| 127 | Contrast Energy, LLC | Tulsa, OK 74119 | Oil & Gas Operator | May 2025 |
| 128 | Convest Energy Corporation | Houston, TX 77057 | Oil & Gas Operator | Sep 2014 |
| 129 | Cordele Development Corporation | San Antonio, TX 78205 | Oil & Gas Operator | May 2025 |
| 130 | Costilla Petroleum Corporation | Midland, TX 79702 | Oil & Gas Operator | Mar 2015 |
| 131 | Cotton, W. L. | Hebbronville, TX 78361 | Oil & Gas Operator | Mar 1996 |
| 132 | Cougar Oil & Gas Co., Inc. | Houston, TX 77269 | Oil & Gas Operator | Mar 2008 |
| 133 | Cox Exploration, Inc. | Dallas, TX 75201 | Oil & Gas Operator | Nov 1999 |
| 134 | Cox, Martin Regan | Irving, TX 75014 | Oil & Gas Operator | May 2025 |
| 135 | Crawford, Linda | Alice, TX 78332 | Oil Operator | May 2025 |
| 136 | Crimson Energy Company, LC | Fort Worth, TX 76102 | Oil & Gas Operator | Mar 2004 |
| 137 | Cross Timbers Energy, LLC | Fort Worth, TX 76102 | Oil & Gas Operator | May 2025 |
| 138 | Cummins & Walker Oil Co., Inc. | Austin, TX 78746 | Oil & Gas Operator | Jan 2021 |
| 139 | CWS Aceite Operating, Inc. | Cotulla, TX 78014 | Oil & Gas Operator | Aug 2018 |
| 140 | Cxy Energy, Inc. | Dallas, TX 75251 | Oil & Gas Operator | Nov 2000 |
| 141 | D-Mil Production Inc | Argyle, TX 76226 | Oil & Gas Operator | May 2025 |
| 142 | Dakota Oil Company | Hebbronville, TX 78361 | Oil & Gas Operator | May 2025 |
| 143 | Dallas Petroleum Group, LLC | Dallas, TX 75379 | Oil & Gas Operator | May 2025 |
| 144 | Davis Asset Management, Inc. | Houston, TX 77010 | Oil & Gas Operator | Dec 2004 |
| 145 | Davis Southern Operating Co LLC | Houston, TX 77004 | Oil & Gas Operator | May 2025 |
| 146 | Delaware Davis Petroleum Corp. | Houston, TX 77056 | Oil & Gas Operator | Jan 2000 |
| 147 | Delray Oil, Inc. | San Antonio, TX 78209 | Oil & Gas Operator | May 2025 |
| 148 | Denali Oil & Gas Management, LLC | Houston, TX 77060 | Oil & Gas Operator | Dec 2012 |
| 149 | Devon Energy Production Company LP | Oklahoma City, OK 73102 | Oil & Gas Operator | May 2025 |
| 150 | Devon Louisiana Corporation | Houston, TX 77002 | Oil & Gas Operator | Oct 2019 |
| 151 | Dewbre Petroleum Corporation | Corpus Chrsti, TX 78404 | Oil & Gas Operator | May 2025 |
| 152 | Digital Operating Company LLC | Boerne, TX 78006 | Oil & Gas Operator | May 2025 |
| 153 | Dirks, R.W. Pet. Eng. Inc. | Tuleta, TX 78162 | Oil & Gas Operator | Jul 1999 |
| 154 | DKW Energy, Inc. | Sherman Oaks, CA 91403 | Oil & Gas Operator | May 2025 |
| 155 | DML Exploration, Inc. | San Antonio, TX 78217 | Oil & Gas Operator | May 2025 |
| 156 | DMS Oil Company | Houston, TX 77042 | Oil & Gas Operator | Mar 2025 |
| 157 | Dolphin Petroleum | Alice, TX 78333 | Oil & Gas Operator | Jun 2008 |
| 158 | Dorado Oil Company | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Oct 2013 |
| 159 | Double Eagle Petroleum Corp | Evansville, IN 47725 | Oil & Gas Operator | May 2025 |
| 160 | Double Play Oil & Gas | Portland, TX 78374 | Oil & Gas Operator | Dec 2001 |
| 161 | Double Play Oil & Gas, Inc | Portland, TX 78374 | Oil & Gas Operator | May 2025 |
| 162 | Drillers Energy Search, Inc | Denver, CO 80202 | Oil & Gas Operator | Aug 1996 |
| 163 | Dynamic Production, Inc. | Fort Worth, TX 76106 | Oil & Gas Operator | May 2025 |
| 164 | Eagle Energy Resources, LLC | La Porte, TX 77571 | Oil & Gas Operator | May 2025 |
| 165 | Eagle Oil & Gas Co. | Dallas, TX 75225 | Oil & Gas Operator | May 2025 |
| 166 | Earthstone Energy, Inc. | The Woodlands, TX 77380 | Oil & Gas Operator | Dec 2017 |
| 167 | Earthstone Operating, LLC | The Woodlands, TX 77380 | Oil & Gas Operator | Mar 2025 |
| 168 | Edge Petroleum Oper. Co., Inc. | Houston, TX 77042 | Oil & Gas Operator | Nov 2010 |
| 169 | Eex Corporation | Houston, TX 77060 | Oil & Gas Operator | Feb 2000 |
| 170 | Eex E&P Company, L.P. | Houston, TX 77060 | Oil & Gas Operator | Jul 2003 |
| 171 | Eex Operating, L.P. | Houston, TX 77060 | Oil & Gas Operator | Jul 2003 |
| 172 | El Dorado Gas & Oil, Inc. | Dallas, TX 75240 | Oil & Gas Operator | May 2025 |
| 173 | El Paso E&P Company, L.P. | Houston, TX 77002 | Oil & Gas Operator | Mar 2013 |
| 174 | El Paso Production Company | Houston, TX 77002 | Oil & Gas Operator | Mar 2016 |
| 175 | El Paso Production Oil & Gas Co. | Houston, TX 77252 | Oil & Gas Operator | May 2025 |
| 176 | Encina Resources, LLC | Houston, TX 77251 | Oil & Gas Operator | May 2025 |
| 177 | Encino Exploration, Inc. | George West, TX 78022 | Oil & Gas Operator | May 2025 |
| 178 | Endeavor Natural Gas, LP | Houston, TX 77002 | Oil & Gas Operator | May 2025 |
| 179 | Energy 2000, Inc. | Reno, NV 89501 | Oil & Gas Operator | May 2025 |
| 180 | Energyquest II, LLC | The Woodlands, TX 77381 | Oil & Gas Operator | Feb 2025 |
| 181 | Enex Resources Corporation | Houston, TX 77002 | Oil & Gas Operator | Dec 2009 |
| 182 | Engroup Resources, L.P. | Houston, TX 77002 | Oil & Gas Operator | May 2025 |
| 183 | Enmark Gas Gathering L. P. | Dallas, TX 75252 | Oil & Gas Operator | Jan 2025 |
| 184 | Enron Oil & Gas Company | Houston, TX 77210 | Oil & Gas Operator | Dec 1999 |
| 185 | Enserch Exploration Inc | Dallas, TX 75206 | Oil & Gas Operator | Apr 2015 |
| 186 | EOG Resources, Inc. | Midland, TX 79702 | Oil & Gas Operator | May 2025 |
| 187 | EP Energy E&P Company, LP | Houston, TX 77210 | Oil & Gas Operator | May 2022 |
| 188 | EP Operating Limited Partnership | Dallas, TX 75201 | Oil & Gas Operator | Feb 1995 |
| 189 | Escondido Resources GP, LLC | Midland, TX 79708 | Oil & Gas Operator | Dec 2007 |
| 190 | Escondido Resources II, LLC | Houston, TX 77002 | Oil & Gas Operator | Apr 2017 |
| 191 | Escondido Resources Oper Co, LLC | Houston, TX 77002 | Oil & Gas Operator | May 2025 |
| 192 | Esenjay Petroleum Corp. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Jul 1998 |
| 193 | Et Gathering & Processing LLC | Dallas, TX 75225 | Oil Operator | Dec 2024 |
| 194 | Etc Texas Pipeline, LTD. | Dallas, TX 75225 | Oil Operator | Sep 2023 |
| 195 | Evans, S. Lavon Jr. Oper. Co. | Laurel, MS 39442 | Oil & Gas Operator | May 2025 |
| 196 | Everest Minerals Corp. | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Apr 2001 |
| 197 | Everest Resource Company | Corpus Chrsti, TX 78403 | Oil & Gas Operator | May 2025 |
| 198 | Evolution Operating Co., Inc. | Houston, TX 77079 | Oil & Gas Operator | May 2025 |
| 199 | Exco Resources Inc | Dallas, TX 75251 | Oil & Gas Operator | Feb 2025 |
| 200 | Exploration Company, The | San Antonio, TX 78258 | Oil & Gas Operator | Jun 2010 |