| 101 | Christopher Oil & Gas Inc | Fulshear, TX 77441 | Oil & Gas Operator | Apr 2015 |
| 102 | Cibolo Energy Operating, Inc. | Bulverde, TX 78163 | Oil & Gas Operator | Oct 2025 |
| 103 | Cico Oil & Gas Company | Houston, TX 77057 | Oil & Gas Operator | Aug 2019 |
| 104 | Cimarron Engineering Corp. | Kingsville, TX 78364 | Oil & Gas Operator | May 2015 |
| 105 | Cimarron Engineering, LLC | Kingsville, TX 78364 | Oil & Gas Operator | Oct 2025 |
| 106 | Clay, Jerry H. | Tyler, TX 75702 | Oil & Gas Operator | Mar 2006 |
| 107 | CLR Gauging Corp. | Tuleta, TX 78162 | Oil & Gas Operator | Oct 2025 |
| 108 | CNG Producing Company | New Orleans, LA 70112 | Oil & Gas Operator | Dec 2015 |
| 109 | Coastal Investments Inc. | El Campo, TX 77437 | Oil & Gas Operator | Oct 2025 |
| 110 | Coastal Oil & Gas Corporation | Houston, TX 77252 | Oil & Gas Operator | Dec 2009 |
| 111 | Coates Energy Trust | San Antonio, TX 78209 | Oil & Gas Operator | Aug 2008 |
| 112 | Cobbs Brothers Oil & Gas | Corpus Chrsti, TX 78476 | Oil & Gas Operator | Jun 2009 |
| 113 | Coker, Jonathan C., Inc. | Austin, TX 78746 | Oil Operator | Mar 2011 |
| 114 | Colemanite, Inc. | Abilene, TX 79606 | Oil & Gas Operator | Oct 2025 |
| 115 | Columbia Gas Development Corp. | Houston, TX 77251 | Oil & Gas Operator | Jun 1996 |
| 116 | Columbus Energy Corp. | Tulsa, OK 74103 | Oil & Gas Operator | Mar 2008 |
| 117 | Conoco Inc. | Houston, TX 77252 | Oil & Gas Operator | Mar 2015 |
| 118 | ConocoPhillips Company | Midland, TX 79701 | Oil & Gas Operator | Oct 2025 |
| 119 | Continental Exploration LLC | Richardson, TX 75080 | Oil & Gas Operator | Oct 2025 |
| 120 | Continental Operating Co. | Houston, TX 77024 | Oil & Gas Operator | Oct 2025 |
| 121 | Contract Oil & Gas Service Co. | Tomball, TX 77375 | Oil & Gas Operator | Apr 2007 |
| 122 | Corda Corporation | Wichita Falls, TX 76308 | Oil & Gas Operator | Oct 2025 |
| 123 | Cordele Development Corporation | San Antonio, TX 78205 | Oil & Gas Operator | Oct 2025 |
| 124 | Core E & P Corp. | Victoria, TX 77902 | Oil & Gas Operator | Oct 2025 |
| 125 | Corenergy Operating Group, LLC | Houston, TX 77074 | Oil & Gas Operator | Oct 2025 |
| 126 | Costilla Energy Inc | Midland, TX 79702 | Oil & Gas Operator | Mar 2008 |
| 127 | Costilla Petroleum Corporation | Midland, TX 79702 | Oil & Gas Operator | Mar 2015 |
| 128 | Crawford Energy Operating Co | Houston, TX 77056 | Oil & Gas Operator | Aug 2008 |
| 129 | Crimson Energy Company, LC | Fort Worth, TX 76102 | Oil & Gas Operator | Mar 2004 |
| 130 | Crimson Exploration Oper., Inc. | Houston, TX 77002 | Oil & Gas Operator | Dec 2019 |
| 131 | Cross Timbers Energy, LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Oct 2025 |
| 132 | Crossroads Energy L.P. | Houston, TX 77064 | Oil & Gas Operator | Jun 2011 |
| 133 | Crossroads Energy Partners, LLC | Houston, TX 77070 | Oil & Gas Operator | Mar 2018 |
| 134 | Crystal River Oil & Gas LLC | Snowmass VLG., CO 81615 | Oil & Gas Operator | Jan 2023 |
| 135 | CTR Petroleum, Inc. | Corpus Chrsti, TX 78414 | Oil & Gas Operator | Mar 2015 |
| 136 | Cumming Company, Inc. The | Fort Worth, TX 76116 | Oil & Gas Operator | Oct 2025 |
| 137 | Cummins & Walker Oil Co., Inc. | Austin, TX 78746 | Oil & Gas Operator | Jan 2021 |
| 138 | CXL Energy LLC | Canada, 00100 | Oil & Gas Operator | Oct 2025 |
| 139 | Cypress E & P Corporation | Leander, TX 78646 | Oil & Gas Operator | Sep 2016 |
| 140 | Dahco Operating, LLC | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Oct 2025 |
| 141 | Dale Operating Company | Dallas, TX 75201 | Oil & Gas Operator | Oct 2025 |
| 142 | Dartex Energy Corporation | Austin, TX 78746 | Oil & Gas Operator | Oct 2025 |
| 143 | Daylight Petroleum LLC | Houston, TX 77052 | Oil & Gas Operator | Oct 2025 |
| 144 | DCP Operating Co LP | Houston, TX 77042 | Oil & Gas Operator | May 2025 |
| 145 | Devon Energy Production Company LP | Oklahoma City, OK 73102 | Oil & Gas Operator | Oct 2025 |
| 146 | Devon Louisiana Corporation | Houston, TX 77002 | Oil & Gas Operator | Oct 2019 |
| 147 | Dewbre Petroleum Corporation | Corpus Chrsti, TX 78404 | Oil & Gas Operator | Oct 2025 |
| 148 | Dinero Oil Corporation | Corpus Chrsti, TX 78460 | Oil & Gas Operator | Nov 1999 |
| 149 | Dirks Petroleum Company | Beeville, TX 78104 | Oil & Gas Operator | Oct 2025 |
| 150 | Dirks, R. W. | Tuleta, TX 78162 | Oil & Gas Operator | May 1999 |
| 151 | Dirnett, Inc. | Tuleta, TX 78162 | Oil & Gas Operator | Oct 2025 |
| 152 | Discovery Energy Corp. CC | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Oct 2025 |
| 153 | Discovery Petroleum, L.L.C. | Alice, TX 78333 | Oil & Gas Operator | Oct 2025 |
| 154 | DML Exploration, Inc. | San Antonio, TX 78217 | Oil & Gas Operator | Oct 2025 |
| 155 | Dominion Exploration & Production Inc | Houston, TX 77060 | Oil & Gas Operator | Apr 2015 |
| 156 | Dominion Minerals Corporation | Houston, TX 77014 | Oil & Gas Operator | Nov 2009 |
| 157 | Dominion Oklahoma Texas E&P, Inc | Richmond, VA 23219 | Oil & Gas Operator | Sep 2018 |
| 158 | Donna-Lynne Oil Co. | George West, TX 78022 | Oil & Gas Operator | Jun 2018 |
| 159 | Dorado Oil Company | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Oct 2013 |
| 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 | Oct 2025 |
| 162 | Dougherty Properties | Beeville, TX 78104 | Oil & Gas Operator | Jun 1997 |
| 163 | Dreyfus, Louis Natural Gas Corp | Oklahoma City, OK 73134 | Oil & Gas Operator | Nov 2001 |
| 164 | Drillers Energy Search, Inc | Denver, CO 80202 | Oil & Gas Operator | Aug 1996 |
| 165 | DRS Exploration Inc. | San Antonio, TX 78209 | Oil & Gas Operator | May 1999 |
| 166 | Durango Resources Corp. | Houston, TX 77043 | Oil & Gas Operator | Oct 2025 |
| 167 | Dynamic Production, Inc. | Fort Worth, TX 76106 | Oil & Gas Operator | Oct 2025 |
| 168 | Eagle Ford Hunter Resources,Inc. | Houston, TX 77024 | Oil & Gas Operator | Apr 2013 |
| 169 | Eastern Oil Corporation | Houston, TX 77070 | Oil & Gas Operator | Oct 2025 |
| 170 | Eclipse Petroleum Corporation | La Grange, TX 78945 | Oil & Gas Operator | Aug 2003 |
| 171 | Eclipse Services, Inc. * | La Grange, TX 78945 | Oil & Gas Operator | Jul 2003 |
| 172 | Edge Petroleum Oper. Co., Inc. | Houston, TX 77042 | Oil & Gas Operator | Nov 2010 |
| 173 | Egan Resources Inc. | Katy, TX 77494 | Oil & Gas Operator | Oct 2016 |
| 174 | El Dorado Resources Inc. | Waco, TX 76710 | Oil & Gas Operator | Oct 2009 |
| 175 | Eldon Oil Co. | Three Rivers, TX 78071 | Oil & Gas Operator | Oct 2025 |
| 176 | Elfco, Inc. | College Sta, TX 77845 | Oil & Gas Operator | Jun 1996 |
| 177 | Elliott Oil & Gas Company | The Woodlands, TX 77380 | Oil & Gas Operator | Sep 2006 |
| 178 | Elliott Oil & Gas Operating Co. | Magnolia, TX 77354 | Oil & Gas Operator | Oct 2025 |
| 179 | Elliott Oil Company, L.P. | Magnolia, TX 77354 | Oil & Gas Operator | Oct 2025 |
| 180 | Ellsworth, H. P. O&G Properties | Corpus Chrsti, TX 78413 | Oil & Gas Operator | Oct 2025 |
| 181 | Emerald Oil & Gas LC | Fort Worth, TX 76109 | Oil & Gas Operator | Oct 2025 |
| 182 | Eminent Oil & Gas, Inc. | Houston, TX 77077 | Oil & Gas Operator | Oct 2025 |
| 183 | Enco Exploration Company | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Apr 2020 |
| 184 | Encore Energy, Inc. | Gainesville, TX 76241 | Oil & Gas Operator | Mar 2015 |
| 185 | Endeavor Natural Gas, LLC | Houston, TX 77002 | Oil & Gas Operator | Feb 2015 |
| 186 | Endeavor Natural Gas, LP | Houston, TX 77002 | Oil & Gas Operator | Oct 2025 |
| 187 | Enduring Resources, LLC | Greenwood VLG, CO 80111 | Oil & Gas Operator | Jul 2025 |
| 188 | Enexco, Inc. | Dallas, TX 75243 | Oil & Gas Operator | Mar 2017 |
| 189 | Enpower Resources Inc. | Sugar Land, TX 77479 | Oil & Gas Operator | Oct 2025 |
| 190 | Enron Oil & Gas Company | Houston, TX 77210 | Oil & Gas Operator | Dec 1999 |
| 191 | Ensign Operating LLC | Houston, TX 77086 | Oil & Gas Operator | Feb 2023 |
| 192 | EOG Resources, Inc. | Midland, TX 79702 | Oil & Gas Operator | Oct 2025 |
| 193 | Erskine Energy, LLC | H SPG NTL PK, AR 71909 | Oil & Gas Operator | Oct 2025 |
| 194 | Esenjay Exploration, Inc | Houston, TX 77042 | Oil & Gas Operator | Jun 2025 |
| 195 | Esenjay Petroleum Corp. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Jul 1998 |
| 196 | Estate Of James L. Nelson | Pettus, TX 78146 | Oil & Gas Operator | Oct 2025 |
| 197 | Etoco Incorporated | Houston, TX 77002 | Oil & Gas Operator | May 2005 |
| 198 | Exp, Inc. | Dallas, TX 75244 | Oil & Gas Operator | May 2003 |
| 199 | Export Petroleum Corporation | Fort Worth, TX 76147 | Oil & Gas Operator | Oct 2025 |
| 200 | Express Oil Co. | Hallettsville, TX 77964 | Oil & Gas Operator | Oct 2025 |