| 101 | Central Energy Producing Company | San Antonio, TX 78217 | Oil & Gas Operator | Sep 2003 |
| 102 | Central Gulf Petroleum Inc | The Woodlands, TX 77380 | Oil & Gas Operator | Apr 2025 |
| 103 | Century Resources, Inc. | Houston, TX 77056 | Oil & Gas Operator | Apr 2025 |
| 104 | Chaparral Energy, L.L.C. | Oklahoma City, OK 73142 | Oil & Gas Operator | Apr 2025 |
| 105 | Chapman Oil Company | Midland, TX 79702 | Oil & Gas Operator | Feb 2025 |
| 106 | Chemily Management Company | Cypress, TX 77429 | Oil & Gas Operator | Apr 2023 |
| 107 | Chesapeake Operating LLC | Oklahoma City, OK 73154 | Oil & Gas Operator | Apr 2025 |
| 108 | Chesapeake Operating, Inc. | Oklahoma City, OK 73154 | Oil & Gas Operator | Dec 2024 |
| 109 | Chevron USA Inc | Midland, TX 79706 | Oil & Gas Operator | Apr 2025 |
| 110 | Cheyenne Petroleum Company | Oklahoma City, OK 73134 | Oil & Gas Operator | Apr 2025 |
| 111 | Churchill Operating, LLC | Houston, TX 77007 | Oil & Gas Operator | Apr 2025 |
| 112 | Cibolo Production, LLC | Boerne, TX 78006 | Oil Operator | Jan 2020 |
| 113 | Cimarex Energy Co | Midland, TX 79706 | Oil & Gas Operator | Apr 2025 |
| 114 | Cimarex Energy Co. Of Colorado | Midland, TX 79706 | Oil & Gas Operator | Apr 2025 |
| 115 | Cimarron Engineering Corp. | Kingsville, TX 78364 | Oil & Gas Operator | May 2015 |
| 116 | Cimarron Engineering, LLC | Kingsville, TX 78364 | Oil & Gas Operator | Apr 2025 |
| 117 | Cinco Natural Resources Corp | La Grange, TX 78945 | Oil & Gas Operator | Apr 2025 |
| 118 | Clayton Williams Energy, Inc. | Houston, TX 77070 | Oil & Gas Operator | Apr 2017 |
| 119 | Clearly Petroleum, LLC | Houston, TX 77086 | Oil & Gas Operator | Jun 2020 |
| 120 | Cliffwood Production Co. | Houston, TX 77090 | Oil & Gas Operator | Aug 2013 |
| 121 | CNG Producing Company | New Orleans, LA 70112 | Oil & Gas Operator | Dec 2015 |
| 122 | Cobbs Brothers Oil & Gas | Corpus Chrsti, TX 78476 | Oil & Gas Operator | Jun 2009 |
| 123 | Cody Energy, Inc. | Houston, TX 77077 | Oil & Gas Operator | Feb 2025 |
| 124 | Cole, Frank W Engineering | Dallas, TX 75254 | Oil & Gas Operator | Mar 2006 |
| 125 | Cologne Production Company | San Antonio, TX 78209 | Oil & Gas Operator | Nov 2014 |
| 126 | Columbia Energy Properties, Inc. | Baytown, TX 77521 | Oil & Gas Operator | Jul 2004 |
| 127 | Columbus Energy, LLC | Houston, TX 77046 | Oil & Gas Operator | Apr 2025 |
| 128 | Comanche Well Service Corp. | Plano, TX 75093 | Oil & Gas Operator | Apr 2025 |
| 129 | Common Resources L.L.C. | The Woodlands, TX 77380 | Oil & Gas Operator | May 2010 |
| 130 | Comstock Oil & Gas, LP | Frisco, TX 75034 | Oil & Gas Operator | Aug 2019 |
| 131 | Conoco Inc. | Houston, TX 77252 | Oil & Gas Operator | Mar 2015 |
| 132 | ConocoPhillips Company | Midland, TX 79701 | Oil & Gas Operator | Apr 2025 |
| 133 | Corpus Christi Leaseholds, Inc. | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Sep 1996 |
| 134 | Costilla Energy Inc | Midland, TX 79702 | Oil & Gas Operator | Mar 2008 |
| 135 | Costilla Petroleum Corporation | Midland, TX 79702 | Oil & Gas Operator | Mar 2015 |
| 136 | Cotton, W. L. | Hebbronville, TX 78361 | Oil & Gas Operator | Mar 1996 |
| 137 | Cox, Martin Regan | Irving, TX 75014 | Oil & Gas Operator | Apr 2025 |
| 138 | Crest Operating Company | Houston, TX 77042 | Oil & Gas Operator | Apr 2025 |
| 139 | Cross Timbers Energy, LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Apr 2025 |
| 140 | CSL Exploration, LP | Houston, TX 77002 | Oil & Gas Operator | Apr 2018 |
| 141 | Cummins & Walker Oil Co., Inc. | Austin, TX 78746 | Oil & Gas Operator | Jan 2021 |
| 142 | CXL Energy LLC | Canada, 00100 | Oil & Gas Operator | Apr 2025 |
| 143 | Cxy Energy, Inc. | Dallas, TX 75251 | Oil & Gas Operator | Nov 2000 |
| 144 | D. O. G. Operating, LLC | Port Aransas, TX 78373 | Oil & Gas Operator | Apr 2025 |
| 145 | Dale Operating Company | Dallas, TX 75201 | Oil & Gas Operator | Apr 2025 |
| 146 | Dallas Production, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Mar 2021 |
| 147 | Dark Horse Producing Of TX, L.P. | Alice, TX 78333 | Oil & Gas Operator | Apr 2025 |
| 148 | DCP Operating Co LP | Houston, TX 77042 | Oil & Gas Operator | Jan 2025 |
| 149 | Dekalb Energy Company | Oklahoma City, OK 73134 | Oil & Gas Operator | Oct 1996 |
| 150 | Delray Oil, Inc. | San Antonio, TX 78209 | Oil & Gas Operator | Apr 2025 |
| 151 | Delta Exploration Company Inc | Denver, CO 80202 | Oil & Gas Operator | Apr 2025 |
| 152 | Devon Energy Operating Co., L.P. | Oklahoma City, OK 73102 | Oil & Gas Operator | Jun 2009 |
| 153 | Devon Energy Production Company LP | Oklahoma City, OK 73102 | Oil & Gas Operator | Apr 2025 |
| 154 | Devon Louisiana Corporation | Houston, TX 77002 | Oil & Gas Operator | Oct 2019 |
| 155 | Dewbre Petroleum Corporation | Corpus Chrsti, TX 78404 | Oil & Gas Operator | Apr 2025 |
| 156 | Dinero Oil Corporation | Corpus Chrsti, TX 78460 | Oil & Gas Operator | Nov 1999 |
| 157 | Dirnett, Inc. | Tuleta, TX 78162 | Oil & Gas Operator | Apr 2025 |
| 158 | DKW Energy, Inc. | Sherman Oaks, CA 91403 | Oil & Gas Operator | Apr 2025 |
| 159 | Dolch Production, Inc. | San Antonio, TX 78248 | Oil & Gas Operator | Jul 1996 |
| 160 | Dolphin Petroleum | Alice, TX 78333 | Oil & Gas Operator | Jun 2008 |
| 161 | Dominion Oklahoma Texas E&P, Inc | Richmond, VA 23219 | Oil & Gas Operator | Sep 2018 |
| 162 | Dorado Drilling, Inc. | Gulfport, MS 39501 | Oil & Gas Operator | Apr 2025 |
| 163 | Dorado Oil Company | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Dec 2014 |
| 164 | Dreyfus, Louis Natural Gas Corp | Oklahoma City, OK 73134 | Oil & Gas Operator | Nov 2001 |
| 165 | Drillers Energy Search, Inc | Denver, CO 80202 | Oil & Gas Operator | Aug 1996 |
| 166 | Driscoll S.W.D. Inc. | San Antonio, TX 78229 | Oil & Gas Operator | Apr 2025 |
| 167 | Dynamic Production, Inc. | Fort Worth, TX 76106 | Oil & Gas Operator | Apr 2025 |
| 168 | Eagle Oil & Gas Co. | Dallas, TX 75225 | Oil & Gas Operator | Apr 2025 |
| 169 | Echo Production Inc | Graham, TX 76450 | Oil & Gas Operator | Apr 2025 |
| 170 | Eclipse Petroleum Corporation | La Grange, TX 78945 | Oil & Gas Operator | Aug 2003 |
| 171 | Edge Petroleum Oper. Co., Inc. | Houston, TX 77042 | Oil & Gas Operator | Nov 2010 |
| 172 | Eex E&P Company, L.P. | Houston, TX 77060 | Oil & Gas Operator | Jul 2003 |
| 173 | Eex Operating, L.P. | Houston, TX 77060 | Oil & Gas Operator | Jul 2003 |
| 174 | Ef Energy, L.L.C. | Houston, TX 77084 | Oil & Gas Operator | Jun 2015 |
| 175 | El Dorado Gas & Oil, Inc. | Dallas, TX 75240 | Oil & Gas Operator | Apr 2025 |
| 176 | El Dorado Resources Inc. | Waco, TX 76710 | Oil & Gas Operator | Oct 2009 |
| 177 | Eldon Oil Co. | Three Rivers, TX 78071 | Oil & Gas Operator | Apr 2025 |
| 178 | Elliott Oil & Gas Operating Co. | Magnolia, TX 77354 | Oil & Gas Operator | Apr 2025 |
| 179 | Ellsworth, H. P. O&G Properties | Corpus Chrsti, TX 78413 | Oil & Gas Operator | Apr 2025 |
| 180 | Endeavor Energy Resources, LP | Midland, TX 79701 | Oil & Gas Operator | Apr 2025 |
| 181 | Energon3 | Rowlett, TX 75089 | Oil Operator | Apr 2025 |
| 182 | Energy Transfer Crude Marketing LLC | Houston, TX 77002 | Oil Operator | Jan 2025 |
| 183 | Energy Transfer Fuel, LP | Houston, TX 77002 | Oil & Gas Operator | Apr 2005 |
| 184 | Enerquest Oil & Gas LLC | Oklahoma City, OK 73114 | Oil & Gas Operator | Jan 2025 |
| 185 | Enerquest Operating, LLC | Oklahoma City, OK 73114 | Oil & Gas Operator | Apr 2025 |
| 186 | Enterprise Crude Oil LLC | Oklahoma City, OK 73102 | Oil Operator | Aug 2011 |
| 187 | EOG Resources, Inc. | Midland, TX 79702 | Oil & Gas Operator | Apr 2025 |
| 188 | EP Energy E&P Company, LLC | Houston, TX 77210 | Oil & Gas Operator | Apr 2025 |
| 189 | EP Energy E&P Company, LP | Houston, TX 77210 | Oil & Gas Operator | May 2022 |
| 190 | Escoba Royalty Corporation | San Antonio, TX 78217 | Oil & Gas Operator | Nov 2005 |
| 191 | Escondido Resources II, LLC | Houston, TX 77002 | Oil & Gas Operator | Apr 2017 |
| 192 | Escondido Resources Oper Co, LLC | Katy, TX 77449 | Oil & Gas Operator | Apr 2025 |
| 193 | Esenjay Petroleum Corp. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Jul 1998 |
| 194 | Espada Operating LLC | San Antonio, TX 78209 | Oil Operator | Apr 2025 |
| 195 | Etc Field Services LLC | San Antonio, TX 78258 | Oil Operator | Jun 2018 |
| 196 | Etc Texas Pipeline, LTD. | Dallas, TX 75225 | Oil Operator | Sep 2023 |
| 197 | Etoco Incorporated | Houston, TX 77002 | Oil & Gas Operator | May 2005 |
| 198 | Excalibur E & P, LLC | Johnson City, TX 78636 | Oil & Gas Operator | Apr 2025 |
| 199 | Exxon Corporation | Houston, TX 77210 | Oil & Gas Operator | Jun 2024 |
| 200 | Exxon Mobil Corporation | Spring, TX 77389 | Oil & Gas Operator | Apr 2025 |