| 101 | CTR Petroleum, Inc. | Corpus Chrsti, TX 78414 | Oil & Gas Operator | Mar 2015 |
| 102 | Cummins & Walker Oil Co., Inc. | Austin, TX 78746 | Oil & Gas Operator | Jan 2021 |
| 103 | D. G. Oil Co. | Dennis, TX 76439 | Oil & Gas Operator | Jul 2025 |
| 104 | D90 Energy, LLC | Houston, TX 77024 | Oil & Gas Operator | Jul 2025 |
| 105 | Dalen Resources Oil & Gas Co. | Dallas, TX 75206 | Oil & Gas Operator | Jun 2010 |
| 106 | Dallas Petroleum Group, LLC | Dallas, TX 75379 | Oil & Gas Operator | Jul 2025 |
| 107 | Davis Petroleum Corp. | Houston, TX 77027 | Oil & Gas Operator | Jul 2025 |
| 108 | DCP Operating Co LP | Houston, TX 77042 | Oil & Gas Operator | Apr 2025 |
| 109 | Deguello Operating LLC | Kilgore, TX 75663 | Oil & Gas Operator | Jul 2025 |
| 110 | Delray Oil, Inc. | San Antonio, TX 78209 | Oil & Gas Operator | Jul 2025 |
| 111 | Denali Oil & Gas Management, LLC | Houston, TX 77060 | Oil & Gas Operator | Dec 2012 |
| 112 | Denovo Oil & Gas, Inc. | Houston, TX 77210 | Oil & Gas Operator | May 1995 |
| 113 | Devon Energy Operating Co., L.P. | Oklahoma City, OK 73102 | Oil & Gas Operator | Jun 2009 |
| 114 | Devon Energy Production Company LP | Oklahoma City, OK 73102 | Oil & Gas Operator | Jul 2025 |
| 115 | Devon Louisiana Corporation | Houston, TX 77002 | Oil & Gas Operator | Oct 2019 |
| 116 | Dewbre Petroleum Corporation | Corpus Chrsti, TX 78404 | Oil & Gas Operator | Jul 2025 |
| 117 | Digital Operating Company LLC | Boerne, TX 78006 | Oil & Gas Operator | Jul 2025 |
| 118 | Dimock Operating Company | Frisco, TX 75034 | Oil & Gas Operator | Jul 2025 |
| 119 | Dinero Oil Corporation | Corpus Chrsti, TX 78460 | Oil & Gas Operator | Nov 1999 |
| 120 | Discorbis Oil Company | San Antonio, TX 78217 | Oil & Gas Operator | Jul 2019 |
| 121 | Dominion Exploration & Production Inc | Houston, TX 77060 | Oil & Gas Operator | Apr 2015 |
| 122 | Dominion Oklahoma Texas E&P, Inc | Richmond, VA 23219 | Oil & Gas Operator | Sep 2018 |
| 123 | Dorado Drilling, Inc. | Gulfport, MS 39501 | Oil & Gas Operator | Jul 2025 |
| 124 | Dorado Oil Company | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Oct 2013 |
| 125 | Double Play Oil & Gas, Inc | Portland, TX 78374 | Oil & Gas Operator | Jul 2025 |
| 126 | Dreyfus, Louis Natural Gas Corp | Oklahoma City, OK 73134 | Oil & Gas Operator | Nov 2001 |
| 127 | Eagle Oil & Gas Co. | Dallas, TX 75225 | Oil & Gas Operator | Jul 2025 |
| 128 | Edge Petroleum Oper. Co., Inc. | Houston, TX 77042 | Oil & Gas Operator | Nov 2010 |
| 129 | Eex Corporation | Houston, TX 77060 | Oil & Gas Operator | Feb 2000 |
| 130 | Eex E&P Company, L.P. | Houston, TX 77060 | Oil & Gas Operator | Jul 2003 |
| 131 | Eex Operating, L.P. | Houston, TX 77060 | Oil & Gas Operator | Jul 2003 |
| 132 | Egan Resources Inc. | Katy, TX 77494 | Oil & Gas Operator | Oct 2016 |
| 133 | El Paso E&P Company, L.P. | Houston, TX 77002 | Oil & Gas Operator | Mar 2013 |
| 134 | El Paso Production Company | Houston, TX 77002 | Oil & Gas Operator | Mar 2016 |
| 135 | El Paso Production Oil & Gas Co. | Houston, TX 77252 | Oil & Gas Operator | Jul 2025 |
| 136 | El Reno Energy, LLC | Granbury, TX 76048 | Oil & Gas Operator | Jul 2025 |
| 137 | Energy + Savings, L.L.C. | Alamo, TX 78516 | Oil & Gas Operator | Jan 2008 |
| 138 | Energy Development Corporation | Houston, TX 77067 | Oil & Gas Operator | Dec 2024 |
| 139 | Enron Oil & Gas Company | Houston, TX 77210 | Oil & Gas Operator | Dec 1999 |
| 140 | Enserch Exploration Inc | Dallas, TX 75206 | Oil & Gas Operator | Apr 2015 |
| 141 | EOG Resources, Inc. | Midland, TX 79702 | Oil & Gas Operator | Jul 2025 |
| 142 | EP Energy E&P Company, LP | Houston, TX 77210 | Oil & Gas Operator | Jan 2023 |
| 143 | Erskine Energy, LLC | H SPG NTL PK, AR 71909 | Oil & Gas Operator | Jul 2025 |
| 144 | Erskine Operating LLC | Houston, TX 77079 | Oil & Gas Operator | Dec 2007 |
| 145 | Escudo Oil & Gas, LLC | Houston, TX 77006 | Oil & Gas Operator | Jul 2025 |
| 146 | Esenjay Petroleum Corp. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Jul 1998 |
| 147 | Export Petroleum Corporation | Fort Worth, TX 76147 | Oil & Gas Operator | Jul 2025 |
| 148 | Extenergy, L.P. | The Woodlands, TX 77380 | Oil & Gas Operator | Dec 2014 |
| 149 | Exxon Corporation | Houston, TX 77210 | Oil & Gas Operator | Jun 2024 |
| 150 | Exxon Mobil Corporation | Spring, TX 77389 | Oil & Gas Operator | Jul 2025 |
| 151 | Falcon Production Co. | Floresville, TX 78114 | Oil & Gas Operator | Jul 2025 |
| 152 | Fargo Oil & Gas, LLC | Corpus Chrsti, TX 78415 | Oil & Gas Operator | Jul 2025 |
| 153 | Faulconer Energy, LLC | Tyler, TX 75711 | Oil & Gas Operator | Jul 2025 |
| 154 | Faulconer Vernon E Inc | Tyler, TX 75711 | Oil & Gas Operator | May 2025 |
| 155 | Fidelity Explor. & Prod. Co. | Denver, CO 80202 | Oil & Gas Operator | Nov 2015 |
| 156 | Fields Exploration, Inc. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Aug 2015 |
| 157 | Fina Oil And Chemical Company | Dallas, TX 75221 | Oil & Gas Operator | May 2019 |
| 158 | Firstrike Energy Corporation | Cleburne, TX 76033 | Oil & Gas Operator | Jan 2025 |
| 159 | Five-Jab, Inc. | Tomball, TX 77377 | Oil & Gas Operator | Jul 2025 |
| 160 | Flairtex Resources, Inc. | Houston, TX 77040 | Oil & Gas Operator | Oct 1998 |
| 161 | Fletcher Operating, LLC | Fairhope, AL 36532 | Oil & Gas Operator | Jul 2025 |
| 162 | Flournoy Production Co. | Alice, TX 78333 | Oil & Gas Operator | Dec 2002 |
| 163 | Fordyce Oil & Gas | Sullivan City, TX 78595 | Oil & Gas Operator | Jul 2022 |
| 164 | Forest Oil Corporation | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 165 | Fortune Resources LLC | Longview, TX 75604 | Oil & Gas Operator | Jul 2025 |
| 166 | Foundation Energy Management, LLC | Addison, TX 75001 | Oil & Gas Operator | Jul 2025 |
| 167 | Fox, Hewitt B., Inc. | Corpus Chrsti, TX 78411 | Oil & Gas Operator | Jul 2025 |
| 168 | Franklin, J.W. Oil Operator | | Oil & Gas Operator | Nov 2001 |
| 169 | Frisco Oil Corporation | Tyler, TX 75701 | Oil & Gas Operator | Mar 2000 |
| 170 | Galilee Oil Investments LLC | San Antonio, TX 78205 | Oil & Gas Operator | Jul 2025 |
| 171 | Gardner Energy Corporation | Houston, TX 77024 | Oil & Gas Operator | Mar 1999 |
| 172 | Gennesaret Investments, LLC | Burleson, TX 76028 | Oil & Gas Operator | Aug 2024 |
| 173 | Gillring Oil Company | Fort Worth, TX 76102 | Oil & Gas Operator | May 1994 |
| 174 | Goldking Prod. Co. | Houston, TX 77002 | Oil & Gas Operator | Apr 1998 |
| 175 | Graham Royalty LTD | Covington, LA 70434 | Oil & Gas Operator | Jul 2007 |
| 176 | Greehey & Company, LTD. | San Antonio, TX 78216 | Oil & Gas Operator | May 2020 |
| 177 | Green Exploration Company | Austin, TX 78711 | Oil & Gas Operator | Jul 2025 |
| 178 | Greenbriar Energy Inc. | Houston, TX 77098 | Oil & Gas Operator | Feb 2004 |
| 179 | Greenbrier Oper. Co. | Dallas, TX 75229 | Oil & Gas Operator | Feb 2001 |
| 180 | Grizzly Op Of Delaware, LLC | Houston, TX 77057 | Oil & Gas Operator | Mar 2021 |
| 181 | Gruy Petroleum Management Co. | Irving, TX 75014 | Oil & Gas Operator | Nov 2014 |
| 182 | Hamilton Brothers Oil Co. | Houston, TX 77057 | Oil & Gas Operator | Mar 2015 |
| 183 | Hampton Resources Corporation | Houston, TX 77010 | Oil & Gas Operator | Mar 1996 |
| 184 | Hanson Minerals Co. | Houston, TX 77042 | Oil & Gas Operator | Oct 1993 |
| 185 | Hanson Production Company | Cuero, TX 77954 | Oil & Gas Operator | Jul 2009 |
| 186 | Hardwick Oil Company | Sugar Land, TX 77478 | Oil & Gas Operator | Nov 2014 |
| 187 | Hawn Brothers | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Apr 2003 |
| 188 | Hawn Brothers Company | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Jan 2003 |
| 189 | Headington Energy Partners, LLC | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Jul 2025 |
| 190 | Headington Oil Company | Dallas, TX 75231 | Oil & Gas Operator | Dec 2016 |
| 191 | Headington Oil Company LLC | Dallas, TX 75204 | Oil & Gas Operator | Apr 2016 |
| 192 | Headington Oil Company, L.P. | Dallas, TX 75231 | Oil & Gas Operator | Mar 2008 |
| 193 | Heritage Operating Co., Inc. The | Stafford, TX 77497 | Oil & Gas Operator | May 1997 |
| 194 | Hibbard Energy, LP | Whitehouse, TX 75791 | Oil & Gas Operator | Jul 2025 |
| 195 | Hilcorp Energy Company | Houston, TX 77208 | Oil & Gas Operator | Jul 2025 |
| 196 | Hope Production, Inc. | Edinburg, TX 78540 | Oil & Gas Operator | Jan 2000 |
| 197 | Houston Exploration Co, The | Houston, TX 77002 | Oil & Gas Operator | Apr 2017 |
| 198 | Houston Oil & Minerals Corp. | Houston, TX 77002 | Oil & Gas Operator | Aug 1996 |
| 199 | Houston Resources Corp. | Houston, TX 77002 | Oil & Gas Operator | Apr 2003 |
| 200 | Howard Exploration, Inc. | Houston, TX 77069 | Oil & Gas Operator | Jul 2025 |