| 101 | Cimarron Engineering Corp. | Kingsville, TX 78364 | Oil & Gas Operator | May 2015 |
| 102 | Coastal Oil & Gas Corporation | Houston, TX 77252 | Oil & Gas Operator | Dec 2009 |
| 103 | Coastal Production Company, Inc. | El Campo, TX 77437 | Oil & Gas Operator | Aug 1995 |
| 104 | Coastline Operating, L.L.C. | Houston, TX 77027 | Oil & Gas Operator | Dec 2006 |
| 105 | Cobra Oil & Gas Corporation | Wichita Falls, TX 76307 | Oil & Gas Operator | Mar 2025 |
| 106 | Cody Energy LLC | Houston, TX 77024 | Oil & Gas Operator | Jun 2020 |
| 107 | Cody Energy, Inc. | Houston, TX 77077 | Oil & Gas Operator | Jan 2025 |
| 108 | Columbia Gas Development Corp. | Houston, TX 77251 | Oil & Gas Operator | Jun 1996 |
| 109 | ConocoPhillips Company | Midland, TX 79701 | Oil & Gas Operator | Mar 2025 |
| 110 | Convest Energy Corporation | Houston, TX 77057 | Oil & Gas Operator | Sep 2014 |
| 111 | Coronado Energy E&P Company, LLC | Houston, TX 77252 | Oil & Gas Operator | Dec 2010 |
| 112 | Cory, Kenneth W. LTD. | Bellaire, TX 77401 | Oil & Gas Operator | Mar 2025 |
| 113 | Costilla Energy Inc | Midland, TX 79702 | Oil & Gas Operator | Mar 2008 |
| 114 | Costilla Petroleum Corporation | Midland, TX 79702 | Oil & Gas Operator | Mar 2015 |
| 115 | Couch, Gilbert | Kilgore, TX 75663 | Oil & Gas Operator | Mar 2025 |
| 116 | Cox & Perkins Exploration, Inc. | Houston, TX 77057 | Oil & Gas Operator | Mar 2025 |
| 117 | Cross Timbers Energy, LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Mar 2025 |
| 118 | CTL Oil & Gas Corporation | Buchanan Dam, TX 78609 | Oil & Gas Operator | Nov 2020 |
| 119 | CTR Petroleum, Inc. | Corpus Chrsti, TX 78414 | Oil & Gas Operator | Mar 2015 |
| 120 | Cummins & Walker Oil Co., Inc. | Austin, TX 78746 | Oil & Gas Operator | Jan 2021 |
| 121 | Cxy Energy, Inc. | Dallas, TX 75251 | Oil & Gas Operator | Nov 2000 |
| 122 | Cypress E & P Corporation | Leander, TX 78646 | Oil & Gas Operator | Sep 2016 |
| 123 | D & P Operating & Prod. Corp. | Cedar Park, TX 78613 | Oil & Gas Operator | Dec 2003 |
| 124 | D-Mil Production Inc | Argyle, TX 76226 | Oil & Gas Operator | Mar 2025 |
| 125 | Dalen Resources Oil & Gas Co. | Dallas, TX 75206 | Oil & Gas Operator | Jun 2010 |
| 126 | Daniels Corporation, The | Seabrook, TX 77586 | Oil & Gas Operator | Mar 2025 |
| 127 | Daylight Petroleum LLC | Houston, TX 77052 | Oil & Gas Operator | Mar 2025 |
| 128 | Delfin Operating, LLC | Dallas, TX 75243 | Oil & Gas Operator | Mar 2025 |
| 129 | Delta Exploration Company Inc | Denver, CO 80202 | Oil & Gas Operator | Mar 2025 |
| 130 | Denovo Oil & Gas, Inc. | Houston, TX 77210 | Oil & Gas Operator | May 1995 |
| 131 | Devon Energy Operating Co., L.P. | Oklahoma City, OK 73102 | Oil & Gas Operator | Jun 2009 |
| 132 | Devon Energy Production Company LP | Oklahoma City, OK 73102 | Oil & Gas Operator | Mar 2025 |
| 133 | Dewbre Petroleum Corporation | Corpus Chrsti, TX 78404 | Oil & Gas Operator | Mar 2025 |
| 134 | Digital Operating Company LLC | Boerne, TX 78006 | Oil & Gas Operator | Mar 2025 |
| 135 | DJ Exploration, Inc. | San Antonio, TX 78257 | Oil & Gas Operator | Mar 2025 |
| 136 | Dominion Exploration & Production Inc | Houston, TX 77060 | Oil & Gas Operator | Apr 2015 |
| 137 | Dorado Oil Company | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Dec 2014 |
| 138 | Double Play Oil & Gas, Inc | Portland, TX 78374 | Oil & Gas Operator | Mar 2025 |
| 139 | Dreyfus, Louis Natural Gas Corp | Oklahoma City, OK 73134 | Oil & Gas Operator | Nov 2001 |
| 140 | Drillmar Operating Company | Houston, TX 77019 | Oil & Gas Operator | Jun 2013 |
| 141 | Dune Operating Company | Dallas, TX 75201 | Oil & Gas Operator | Jun 2016 |
| 142 | Dynamic Production, Inc. | Fort Worth, TX 76106 | Oil & Gas Operator | Mar 2025 |
| 143 | E.G. Operating | Dallas, TX 75206 | Oil & Gas Operator | Mar 2008 |
| 144 | Eagle Oil & Gas Co. | Dallas, TX 75225 | Oil & Gas Operator | Mar 2025 |
| 145 | Eei Operating Inc. | Plano, TX 75093 | Oil & Gas Operator | May 2015 |
| 146 | Eex Corporation | Houston, TX 77060 | Oil & Gas Operator | Feb 2000 |
| 147 | Eex Operating, L.P. | Houston, TX 77060 | Oil & Gas Operator | Jul 2003 |
| 148 | El Paso E&P Company, L.P. | Houston, TX 77002 | Oil & Gas Operator | Mar 2013 |
| 149 | El Reno Energy, LLC | Granbury, TX 76048 | Oil & Gas Operator | Mar 2025 |
| 150 | Elliott Oil & Gas Company | The Woodlands, TX 77380 | Oil & Gas Operator | Sep 2006 |
| 151 | Elliott Oil & Gas Operating Co. | Magnolia, TX 77354 | Oil & Gas Operator | Mar 2025 |
| 152 | Encana Oil & Gas (USA) Inc. | Denver, CO 80202 | Oil & Gas Operator | Oct 2020 |
| 153 | Endeavor Energy Resources, LP | Midland, TX 79701 | Oil & Gas Operator | Mar 2025 |
| 154 | Endeavor Natural Gas, LP | Houston, TX 77002 | Oil & Gas Operator | Mar 2025 |
| 155 | Enercorp Resources, Inc. | Houston, TX 77027 | Oil & Gas Operator | Dec 1993 |
| 156 | Energy Development Corporation | Houston, TX 77067 | Oil & Gas Operator | Dec 2024 |
| 157 | Energy Transfer Crude Marketing LLC | Houston, TX 77002 | Oil Operator | Dec 2024 |
| 158 | Enerquest Oil & Gas LLC | Oklahoma City, OK 73114 | Oil & Gas Operator | Dec 2024 |
| 159 | Enervest Operating LLC | Houston, TX 77002 | Oil & Gas Operator | Mar 2025 |
| 160 | Enhanced Energy Partners Corp | Tomball, TX 77377 | Oil & Gas Operator | Mar 2025 |
| 161 | Enron Oil & Gas Company | Houston, TX 77210 | Oil & Gas Operator | Dec 1999 |
| 162 | Enserch Exploration Inc | Dallas, TX 75206 | Oil & Gas Operator | Apr 2015 |
| 163 | Enserch Oil & Gas, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Mar 1998 |
| 164 | EOG Resources, Inc. | Midland, TX 79702 | Oil & Gas Operator | Mar 2025 |
| 165 | EP Energy E&P Company, LP | Houston, TX 77210 | Oil & Gas Operator | May 2022 |
| 166 | EP Operating Limited Partnership | Dallas, TX 75201 | Oil & Gas Operator | Feb 1995 |
| 167 | Escoba Royalty Corporation | San Antonio, TX 78217 | Oil & Gas Operator | Nov 2005 |
| 168 | Esenjay Petroleum Corp. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Jul 1998 |
| 169 | Etoco Incorporated | Houston, TX 77002 | Oil & Gas Operator | May 2005 |
| 170 | Everest Minerals Corp. | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Apr 2001 |
| 171 | Everest Resource Company | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Mar 2025 |
| 172 | Export Petroleum Corporation | Fort Worth, TX 76147 | Oil & Gas Operator | Mar 2025 |
| 173 | Express Oil Co. | Hallettsville, TX 77964 | Oil & Gas Operator | Mar 2025 |
| 174 | Exxon Corporation | Houston, TX 77210 | Oil & Gas Operator | Jun 2024 |
| 175 | Exxon Mobil Corporation | Spring, TX 77389 | Oil & Gas Operator | Mar 2025 |
| 176 | Famcor Oil, Inc. | Scottsdale, AZ 85260 | Oil & Gas Operator | Sep 2020 |
| 177 | Faulconer Energy, LLC | Tyler, TX 75711 | Oil & Gas Operator | Mar 2025 |
| 178 | Fieldwood Onshore LLC | Houston, TX 77098 | Oil & Gas Operator | Mar 2025 |
| 179 | Finley Resources Inc | Fort Worth, TX 76113 | Oil & Gas Operator | Mar 2025 |
| 180 | Firstrike Energy Corporation | Cleburne, TX 76033 | Oil & Gas Operator | Jan 2025 |
| 181 | Five-Jab, Inc. | Tomball, TX 77377 | Oil & Gas Operator | Mar 2025 |
| 182 | Fletcher Operating, LLC | Fairhope, AL 36533 | Oil & Gas Operator | Mar 2025 |
| 183 | Force 4 Energy Resources, Inc. | Austin, TX 78733 | Oil & Gas Operator | Aug 2005 |
| 184 | Fore Oil, LLC | Manvel, TX 77578 | Oil Operator | May 2021 |
| 185 | Fortune Natural Resources Corp. | Houston, TX 77067 | Oil & Gas Operator | Dec 2003 |
| 186 | Forza Operating, LLC | The Woodlands, TX 77380 | Oil & Gas Operator | Mar 2025 |
| 187 | Frio Exploration Company | Pearland, TX 77588 | Oil & Gas Operator | Dec 2000 |
| 188 | Gaither Petroleum Corporation | Katy, TX 77493 | Oil & Gas Operator | Mar 2025 |
| 189 | Galloway Energy Co. | Tomball, TX 77377 | Oil & Gas Operator | Mar 2025 |
| 190 | Gardner Energy Corporation | Houston, TX 77024 | Oil & Gas Operator | Mar 1999 |
| 191 | Garrison LTD. | San Antonio, TX 78257 | Oil & Gas Operator | Mar 2025 |
| 192 | Gasper Rice Resources, LTD. | Houston, TX 77068 | Oil & Gas Operator | Mar 2025 |
| 193 | Gec Operating, Inc. | Houston, TX 77024 | Oil & Gas Operator | Mar 2025 |
| 194 | Geiser Operating, Inc. | Portland, TX 78374 | Oil & Gas Operator | Sep 2019 |
| 195 | Gel Petroleum, Inc. | Bay City, TX 77414 | Oil & Gas Operator | Mar 2025 |
| 196 | Gemarmi Inc. | Cypress, TX 77433 | Oil & Gas Operator | Mar 2025 |
| 197 | Genesis Crude Oil LP | Houston, TX 77002 | Oil & Gas Operator | Apr 2000 |
| 198 | Geodominion Petroleum | Corpus Chrsti, TX 78403 | Oil & Gas Operator | May 2012 |
| 199 | Geosouthern Energy Corporation | The Woodlands, TX 77380 | Oil & Gas Operator | Mar 2025 |
| 200 | Germany Operating Company | Houston, TX 77090 | Oil & Gas Operator | Sep 2011 |