| 101 | Costilla Petroleum Corporation | Midland, TX 79702 | Oil & Gas Operator | Mar 2015 |
| 102 | Cotton, W. L. | Hebbronville, TX 78361 | Oil & Gas Operator | Mar 1996 |
| 103 | Covenant Oil & Gas, L.P. | Houston, TX 77057 | Oil & Gas Operator | Dec 2006 |
| 104 | Cox & Perkins Exploration, Inc. | Houston, TX 77057 | Oil & Gas Operator | Oct 2025 |
| 105 | Cox Exploration, Inc. | Dallas, TX 75201 | Oil & Gas Operator | Nov 1999 |
| 106 | Cox Resources Corporation | Dallas, TX 75244 | Oil & Gas Operator | Mar 2015 |
| 107 | Crimson Energy Company, LC | Fort Worth, TX 76102 | Oil & Gas Operator | Mar 2004 |
| 108 | Cummins & Walker Oil Co., Inc. | Austin, TX 78746 | Oil & Gas Operator | Jan 2021 |
| 109 | CWS Aceite Operating, Inc. | Cotulla, TX 78014 | Oil & Gas Operator | Aug 2018 |
| 110 | D&H-S-S Production Co.,Inc | Corpus Chrsti, TX 78409 | Oil & Gas Operator | Aug 2003 |
| 111 | Dalen Resources Oil & Gas Co. | Dallas, TX 75206 | Oil & Gas Operator | Jun 2010 |
| 112 | Dallas Petroleum Group, LLC | Dallas, TX 75379 | Oil & Gas Operator | Oct 2025 |
| 113 | Dalport Oil Corporation | Dallas, TX 75202 | Oil & Gas Operator | Apr 1993 |
| 114 | Davis Petroleum Corp. | Houston, TX 77027 | Oil & Gas Operator | Oct 2025 |
| 115 | Dekalb Energy Company | Oklahoma City, OK 73134 | Oil & Gas Operator | Oct 1996 |
| 116 | Dewbre Petroleum Corporation | Corpus Chrsti, TX 78404 | Oil & Gas Operator | Oct 2025 |
| 117 | Dinero Oil Corporation | Corpus Chrsti, TX 78460 | Oil & Gas Operator | Nov 1999 |
| 118 | Dirnett, Inc. | Tuleta, TX 78162 | Oil & Gas Operator | Oct 2025 |
| 119 | DKW Energy, Inc. | Sherman Oaks, CA 91403 | Oil & Gas Operator | Oct 2025 |
| 120 | DML Exploration, Inc. | San Antonio, TX 78217 | Oil & Gas Operator | Oct 2025 |
| 121 | Dogwood Operating Company, Inc. | Houston, TX 77069 | Oil & Gas Operator | Oct 2025 |
| 122 | Dolphin Petroleum | Alice, TX 78333 | Oil & Gas Operator | Jun 2008 |
| 123 | Dolphin Petroleum, LP | Alice, TX 78333 | Oil & Gas Operator | Oct 2025 |
| 124 | Dominion Oklahoma Texas E&P, Inc | Richmond, VA 23219 | Oil & Gas Operator | Sep 2018 |
| 125 | Dorado Oil Company | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Oct 2013 |
| 126 | Double Play Oil & Gas | Portland, TX 78374 | Oil & Gas Operator | Dec 2001 |
| 127 | Double Play Oil & Gas, Inc | Portland, TX 78374 | Oil & Gas Operator | Oct 2025 |
| 128 | Dove Creek Energy, Inc. | Fort Worth, TX 76121 | Oil & Gas Operator | Oct 2025 |
| 129 | Dreyfus, Louis Natural Gas Corp | Oklahoma City, OK 73134 | Oil & Gas Operator | Nov 2001 |
| 130 | Drillers Energy Search, Inc | Denver, CO 80202 | Oil & Gas Operator | Aug 1996 |
| 131 | Durango Resources Corp. | Houston, TX 77043 | Oil & Gas Operator | Oct 2025 |
| 132 | Durst Oil Company | Corpus Chrsti, TX 78477 | Oil & Gas Operator | Sep 2000 |
| 133 | Earthstone Energy, Inc. | The Woodlands, TX 77380 | Oil & Gas Operator | Dec 2017 |
| 134 | Eclipse Services, Inc. * | La Grange, TX 78945 | Oil & Gas Operator | Jul 2003 |
| 135 | Edge Petroleum Oper. Co., Inc. | Houston, TX 77042 | Oil & Gas Operator | Nov 2010 |
| 136 | El Dorado Resources Inc. | Waco, TX 76710 | Oil & Gas Operator | Oct 2009 |
| 137 | El Paso E&P Company, L.P. | Houston, TX 77002 | Oil & Gas Operator | Mar 2013 |
| 138 | El Paso Production Oil & Gas Co. | Houston, TX 77252 | Oil & Gas Operator | Oct 2025 |
| 139 | Eland Energy Inc | Dallas, TX 75248 | Oil & Gas Operator | Jul 2025 |
| 140 | Elliott Oil & Gas Company | The Woodlands, TX 77380 | Oil & Gas Operator | Sep 2006 |
| 141 | Elliott Oil & Gas Operating Co. | Magnolia, TX 77354 | Oil & Gas Operator | Oct 2025 |
| 142 | Ellsworth, H. P. O&G Properties | Corpus Chrsti, TX 78413 | Oil & Gas Operator | Oct 2025 |
| 143 | Encana Oil & Gas (USA) Inc. | Denver, CO 80202 | Oil & Gas Operator | Oct 2020 |
| 144 | Encino Exploration, Inc. | George West, TX 78022 | Oil & Gas Operator | Oct 2025 |
| 145 | Endeavor Production Company | San Angelo, TX 76904 | Oil & Gas Operator | Mar 2008 |
| 146 | Energen Resources Corporation | Midland, TX 79701 | Oil & Gas Operator | Jan 2021 |
| 147 | EOG Resources, Inc. | Midland, TX 79702 | Oil & Gas Operator | Oct 2025 |
| 148 | EP Energy E&P Company, LP | Houston, TX 77210 | Oil & Gas Operator | Jan 2023 |
| 149 | Ernest Operating Company | Rockdale, TX 76567 | Oil & Gas Operator | Oct 2025 |
| 150 | Esenjay Exploration, Inc | Houston, TX 77042 | Oil & Gas Operator | Jun 2025 |
| 151 | Esenjay Petroleum Corp. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Jul 1998 |
| 152 | Etoco, L.P. | Houston, TX 77002 | Oil & Gas Operator | Oct 2025 |
| 153 | Everest Resource Company | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Oct 2025 |
| 154 | Excalibur E & P, LLC | Johnson City, TX 78636 | Oil & Gas Operator | Oct 2025 |
| 155 | Export Petroleum Corporation | Fort Worth, TX 76147 | Oil & Gas Operator | Oct 2025 |
| 156 | Expro Engineering, Inc. | Fort Worth, TX 76179 | Oil & Gas Operator | Oct 2025 |
| 157 | Exxon Corporation | Houston, TX 77210 | Oil & Gas Operator | Jun 2024 |
| 158 | Exxon Mobil Corporation | Spring, TX 77389 | Oil & Gas Operator | Oct 2025 |
| 159 | Famcor Oil, Inc. | Scottsdale, AZ 85260 | Oil & Gas Operator | Sep 2020 |
| 160 | Ffa Petroleum Services | Victoria, TX 77903 | Oil & Gas Operator | Sep 2001 |
| 161 | Fields Exploration, Inc. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Aug 2015 |
| 162 | Fina Oil And Chemical Company | Dallas, TX 75221 | Oil & Gas Operator | May 2019 |
| 163 | Firstrike Energy Corporation | Cleburne, TX 76033 | Oil & Gas Operator | Jan 2025 |
| 164 | Fischer Operating Corporation | Victoria, TX 77902 | Oil & Gas Operator | Jan 1999 |
| 165 | Five-Jab, Inc. | Tomball, TX 77377 | Oil & Gas Operator | Oct 2025 |
| 166 | Flournoy Production Co. | Alice, TX 78333 | Oil & Gas Operator | Dec 2002 |
| 167 | Flow Production Company | Midland, TX 79708 | Oil & Gas Operator | Mar 2005 |
| 168 | Forza Operating, LLC | The Woodlands, TX 77380 | Oil & Gas Operator | Oct 2025 |
| 169 | Fox, Hewitt B., Inc. | Corpus Chrsti, TX 78411 | Oil & Gas Operator | Oct 2025 |
| 170 | Fredonia Resources Inc. | Longview, TX 75606 | Oil & Gas Operator | Aug 2003 |
| 171 | Friendly Energy Services, Inc. | Corpus Chrsti, TX 78410 | Oil & Gas Operator | Oct 2025 |
| 172 | Frio Exploration Company | Pearland, TX 77588 | Oil & Gas Operator | Dec 2000 |
| 173 | Frostwood Energy, LLC | Houston, TX 77219 | Oil & Gas Operator | Oct 2025 |
| 174 | Future Petroleum Corporation | Houston, TX 77002 | Oil & Gas Operator | Sep 1999 |
| 175 | Gaither Petroleum Corporation | Katy, TX 77493 | Oil & Gas Operator | Oct 2025 |
| 176 | Gasper Rice Resources, LTD. | Houston, TX 77068 | Oil & Gas Operator | Oct 2025 |
| 177 | Geiser Operating, Inc. | Portland, TX 78374 | Oil & Gas Operator | Sep 2019 |
| 178 | Gemarmi Inc. | Cypress, TX 77433 | Oil & Gas Operator | Oct 2025 |
| 179 | Geodominion Petroleum | Corpus Chrsti, TX 78403 | Oil & Gas Operator | May 2012 |
| 180 | Geronimo Oil Co. | Corpus Chrsti, TX 78476 | Oil & Gas Operator | Mar 2008 |
| 181 | Gillring Oil Company | Fort Worth, TX 76102 | Oil & Gas Operator | May 1994 |
| 182 | Global Natural Resources Corp. | Houston, TX 77002 | Oil & Gas Operator | May 1998 |
| 183 | Gohlke Farms, Inc. | Corpus Chrsti, TX 78418 | Oil & Gas Operator | Aug 2011 |
| 184 | Goldking Prod. Co. | Houston, TX 77002 | Oil & Gas Operator | Apr 1998 |
| 185 | Goodrich Pet. Co. Of Louisiana | Houston, TX 77002 | Oil & Gas Operator | Mar 2008 |
| 186 | Goodrich Petroleum Company | Houston, TX 77002 | Oil & Gas Operator | Feb 2022 |
| 187 | Gordy Oil Company | Houston, TX 77007 | Oil & Gas Operator | Oct 2025 |
| 188 | Grace Petroleum Corp. | Tulsa, OK 74103 | Oil & Gas Operator | Oct 1997 |
| 189 | Graham Royalty LTD | Covington, LA 70434 | Oil & Gas Operator | Jul 2007 |
| 190 | Great Texas Crude Inc. | Fredericksbrg, TX 78624 | Oil & Gas Operator | Oct 2025 |
| 191 | Green Exploration Company | Austin, TX 78711 | Oil & Gas Operator | Oct 2025 |
| 192 | GTG Operating, LLC | Tyler, TX 75702 | Oil & Gas Operator | Oct 2025 |
| 193 | H & P Exploration Co. | Alice, TX 78333 | Oil & Gas Operator | May 2019 |
| 194 | H H Exploration, Inc. | Incline VLLG, NV 89451 | Gas Operator | Feb 2018 |
| 195 | Haas, C. F. Oil & Gas Inc. | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Oct 2025 |
| 196 | Hallwood Petroleum, Inc. | Midland, TX 79701 | Oil & Gas Operator | Jun 2025 |
| 197 | Hardwick Oil Company | Sugar Land, TX 77478 | Oil & Gas Operator | Nov 2014 |
| 198 | Haring Energy Company | Tuleta, TX 78162 | Oil & Gas Operator | Mar 2003 |
| 199 | Harper Hefte, Inc. | Corpus Chrsti, TX 78410 | Oil & Gas Operator | Oct 2025 |
| 200 | Harrigan Operating, LLC | Houston, TX 77258 | Oil & Gas Operator | Apr 2020 |