| 101 | Chesapeake Operating LLC | Oklahoma City, OK 73154 | Oil & Gas Operator | Mar 2025 |
| 102 | Chesapeake Operating, Inc. | Oklahoma City, OK 73154 | Oil & Gas Operator | Nov 2024 |
| 103 | Chestnut Explor. And Prod., Inc. | Dallas, TX 75208 | Oil & Gas Operator | Mar 2025 |
| 104 | Chevron Midcontinent, L.P. | Midland, TX 79706 | Oil & Gas Operator | Mar 2025 |
| 105 | Chilton Energy | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Sep 2006 |
| 106 | Chisholm Oil & Gas, LC | Buda, TX 78610 | Oil & Gas Operator | Mar 2025 |
| 107 | Chisos, LTD | Houston, TX 77098 | Oil & Gas Operator | Mar 2025 |
| 108 | Choctaw Resources, Inc. | Aledo, TX 76008 | Oil & Gas Operator | Dec 2019 |
| 109 | Choice Exploration, Inc. | Irving, TX 75063 | Oil & Gas Operator | Mar 2025 |
| 110 | CHP Oil & Gas Company, L.C. | El Campo, TX 77437 | Oil & Gas Operator | Mar 2025 |
| 111 | Christeve Oil Company, Inc. | Houston, TX 77068 | Oil & Gas Operator | Dec 2022 |
| 112 | Cibolo Energy Operating, Inc. | Bulverde, TX 78163 | Oil & Gas Operator | Mar 2025 |
| 113 | Cimarex Energy Co Of Colorado | Midland, TX 79706 | Oil & Gas Operator | Mar 2025 |
| 114 | Cimarron Engineering Corp. | Kingsville, TX 78364 | Oil & Gas Operator | May 2015 |
| 115 | Cimarron Engineering, LLC | Kingsville, TX 78364 | Oil & Gas Operator | Mar 2025 |
| 116 | Citation Oil & Gas Corp. | Houston, TX 77269 | Oil & Gas Operator | Mar 2025 |
| 117 | Click Corp | Monroe, LA 71207 | Oil & Gas Operator | Jan 2025 |
| 118 | Clsog L.C. | Houston, TX 77024 | Gas Operator | Jun 2008 |
| 119 | Coastal Investments Inc. | El Campo, TX 77437 | Oil & Gas Operator | Mar 2025 |
| 120 | Coastal Oil & Gas Corporation | Houston, TX 77252 | Oil & Gas Operator | Dec 2009 |
| 121 | Coastal Production Company, Inc. | El Campo, TX 77437 | Oil & Gas Operator | Aug 1995 |
| 122 | Coastline Exploration, Inc. | Stafford, TX 77477 | Oil & Gas Operator | Mar 2025 |
| 123 | Coates Energy Interests, LTD. | San Antonio, TX 78217 | Oil & Gas Operator | Aug 1997 |
| 124 | Cockburn Oil Corporation | Lubbock, TX 79493 | Oil & Gas Operator | Jul 2005 |
| 125 | Colo Exploration Company, Inc. | Benbrook, TX 76126 | Oil & Gas Operator | Mar 2025 |
| 126 | Columbia Gas Development Corp. | Houston, TX 77251 | Oil & Gas Operator | Jun 1996 |
| 127 | Columbus Energy, LLC | Houston, TX 77046 | Oil & Gas Operator | Mar 2025 |
| 128 | Common Resources L.L.C. | The Woodlands, TX 77380 | Oil & Gas Operator | May 2010 |
| 129 | Conoco Inc. | Houston, TX 77252 | Oil & Gas Operator | Mar 2015 |
| 130 | ConocoPhillips Company | Midland, TX 79701 | Oil & Gas Operator | Mar 2025 |
| 131 | Cons Asset MGMT SVCS E&P Op, LLC | Houston, TX 77002 | Oil Operator | Dec 2017 |
| 132 | Contango Resources, Inc. | Houston, TX 77002 | Oil & Gas Operator | Feb 2025 |
| 133 | Continental Operating Co. | Houston, TX 77024 | Oil & Gas Operator | Mar 2025 |
| 134 | Contour Energy E & P, Inc. | Houston, TX 77002 | Oil & Gas Operator | Oct 2002 |
| 135 | Contour Energy E & P, LLC | Tulsa, OK 74103 | Oil & Gas Operator | Aug 2003 |
| 136 | Contour Oil & Gas, LLC | Abilene, TX 79602 | Oil & Gas Operator | Dec 2015 |
| 137 | Convest Energy Corporation | Houston, TX 77057 | Oil & Gas Operator | Sep 2014 |
| 138 | Cordele Development Corporation | San Antonio, TX 78205 | Oil & Gas Operator | Mar 2025 |
| 139 | Core E & P Corp. | Victoria, TX 77902 | Oil & Gas Operator | Mar 2025 |
| 140 | Cortex Energy, Inc. | Wichita, KS 67217 | Oil & Gas Operator | Dec 2024 |
| 141 | Corum Operating Company, LLC | Houston, TX 77055 | Oil & Gas Operator | Mar 2025 |
| 142 | Cox & Perkins Exploration, Inc. | Houston, TX 77057 | Oil & Gas Operator | Mar 2025 |
| 143 | Crawford Energy Operating Co | Houston, TX 77056 | Oil & Gas Operator | Aug 2008 |
| 144 | Crest Petroleum, LLC | Wichita Falls, TX 76301 | Oil & Gas Operator | Mar 2025 |
| 145 | Crest Resources & Expl. Corp. | Houston, TX 77079 | Oil & Gas Operator | Dec 1998 |
| 146 | Crimson Exploration Oper., Inc. | Houston, TX 77002 | Oil & Gas Operator | Dec 2019 |
| 147 | CTR Petroleum, Inc. | Corpus Chrsti, TX 78414 | Oil & Gas Operator | Mar 2015 |
| 148 | Cummins & Walker Oil Co., Inc. | Austin, TX 78746 | Oil & Gas Operator | Jan 2021 |
| 149 | Cyclone Exploration, Inc. | Florence, CO 81226 | Oil & Gas Operator | Mar 2025 |
| 150 | Cypress E & P Corporation | Leander, TX 78646 | Oil & Gas Operator | Sep 2016 |
| 151 | Cypress Production, Inc. | Azle, TX 76020 | Oil & Gas Operator | Mar 2025 |
| 152 | D-Mil Production Inc | Argyle, TX 76226 | Oil & Gas Operator | Mar 2025 |
| 153 | Dalen Resources Oil & Gas Co. | Dallas, TX 75206 | Oil & Gas Operator | Jun 2010 |
| 154 | Dallas Petroleum Group, LLC | Dallas, TX 75379 | Oil & Gas Operator | Mar 2025 |
| 155 | Dartex Energy Corporation | Austin, TX 78746 | Oil & Gas Operator | Mar 2025 |
| 156 | Davis Gulf Coast, Inc. | Tulsa, OK 74103 | Oil & Gas Operator | Mar 2025 |
| 157 | DCP Operating Co LP | Houston, TX 77042 | Oil & Gas Operator | Dec 2024 |
| 158 | Decker Operating Co., L.L.C. | Houston, TX 77008 | Oil & Gas Operator | Mar 2025 |
| 159 | Delco Operating Company LP | Houston, TX 77056 | Oil & Gas Operator | May 2020 |
| 160 | Denali Oil & Gas Management, LLC | Houston, TX 77060 | Oil & Gas Operator | Dec 2012 |
| 161 | Dewbre Petroleum Corporation | Corpus Chrsti, TX 78404 | Oil & Gas Operator | Mar 2025 |
| 162 | Dillon, H. L., Jr. | Houston, TX 77027 | Oil & Gas Operator | Mar 1996 |
| 163 | Dinero Oil Corporation | Corpus Chrsti, TX 78460 | Oil & Gas Operator | Nov 1999 |
| 164 | Discovery Energy Corp. CC | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Mar 2025 |
| 165 | DJ Exploration, Inc. | San Antonio, TX 78257 | Oil & Gas Operator | Mar 2025 |
| 166 | Dominion Oklahoma Texas E&P, Inc | Richmond, VA 23219 | Oil & Gas Operator | Sep 2018 |
| 167 | Dorado Oil Company | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Dec 2014 |
| 168 | Double Eagle Petroleum Corp | Evansville, IN 47725 | Oil & Gas Operator | Mar 2025 |
| 169 | Double Play Oil & Gas, Inc | Portland, TX 78374 | Oil & Gas Operator | Mar 2025 |
| 170 | Double S Operating Co. | Wichita Falls, TX 76308 | Oil & Gas Operator | Mar 2025 |
| 171 | Drachen Oil Company | San Antonio, TX 78258 | Oil & Gas Operator | Mar 2025 |
| 172 | Dreyfus, Louis Natural Gas Corp | Oklahoma City, OK 73134 | Oil & Gas Operator | Nov 2001 |
| 173 | Drillmar Energy, Inc. | Houston, TX 77079 | Oil & Gas Operator | Nov 2014 |
| 174 | Drillmar Operating Company | Houston, TX 77019 | Oil & Gas Operator | Jun 2013 |
| 175 | Driscoll S.W.D. Inc. | San Antonio, TX 78229 | Oil & Gas Operator | Mar 2025 |
| 176 | Duncan Oil Inc | Denver, CO 80210 | Oil & Gas Operator | Jun 2016 |
| 177 | Dune Operating Company | Dallas, TX 75201 | Oil & Gas Operator | Jun 2016 |
| 178 | Dynamic Of Texas, Inc. | Lafayette, LA 70505 | Oil & Gas Operator | Aug 2003 |
| 179 | E.G. Operating | Dallas, TX 75206 | Oil & Gas Operator | Mar 2008 |
| 180 | Eagle Energy Development Co | La Porte, TX 77571 | Oil & Gas Operator | Dec 2024 |
| 181 | Eagle Energy Resources, LLC | La Porte, TX 77571 | Oil & Gas Operator | Mar 2025 |
| 182 | Eagle Oil & Gas Co. | Dallas, TX 75225 | Oil & Gas Operator | Mar 2025 |
| 183 | East Texas Production MGT. Inc | Athens, TX 75751 | Oil & Gas Operator | Mar 2025 |
| 184 | Eex Corporation | Houston, TX 77060 | Oil & Gas Operator | Feb 2000 |
| 185 | Egan Resources Inc. | Katy, TX 77494 | Oil & Gas Operator | Oct 2016 |
| 186 | Eland Energy Inc | Dallas, TX 75248 | Oil & Gas Operator | Jan 2025 |
| 187 | Ellsworth, H. P. O&G Properties | Corpus Chrsti, TX 78413 | Oil & Gas Operator | Mar 2025 |
| 188 | Emerald Oil & Gas LC | Fort Worth, TX 76109 | Oil & Gas Operator | Mar 2025 |
| 189 | Encon Services, Inc. | Abilene, TX 79608 | Oil & Gas Operator | Mar 2025 |
| 190 | Energy Development Corporation | Houston, TX 77067 | Oil & Gas Operator | Dec 2024 |
| 191 | Energy Transfer Crude Marketing LLC | Houston, TX 77002 | Oil Operator | Dec 2024 |
| 192 | Engelke, R. H. | San Antonio, TX 78230 | Oil & Gas Operator | Mar 2025 |
| 193 | Enron Oil & Gas Company | Houston, TX 77210 | Oil & Gas Operator | Dec 1999 |
| 194 | Enserch Exploration Inc | Dallas, TX 75206 | Oil & Gas Operator | Apr 2015 |
| 195 | EP Operating Limited Partnership | Dallas, TX 75201 | Oil & Gas Operator | Feb 1995 |
| 196 | Ermis Vacuum Service | El Campo, TX 77437 | Oil & Gas Operator | Mar 2010 |
| 197 | Esenjay Petroleum Corp. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Jul 1998 |
| 198 | Everest Minerals Corp. | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Apr 2001 |
| 199 | Everest Resource Company | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Mar 2025 |
| 200 | Exco Resources Inc | Dallas, TX 75251 | Oil & Gas Operator | Dec 2024 |