| 101 | D-Mil Production Inc | Argyle, TX 76226 | Oil & Gas Operator | May 2025 |
| 102 | Daf Operating, LLC | Houston, TX 77005 | Oil & Gas Operator | May 2025 |
| 103 | Dallas Operating Corp. | Dallas, TX 75205 | Oil & Gas Operator | Nov 2006 |
| 104 | Daniels Corporation, The | Seabrook, TX 77586 | Oil & Gas Operator | May 2025 |
| 105 | Daubert Operating, L.L.C. | San Antonio, TX 78209 | Oil Operator | May 2025 |
| 106 | Davis Bros. Oil Producers, Inc. | Tulsa, OK 74119 | Oil & Gas Operator | Apr 2020 |
| 107 | Daylight Petroleum LLC | Houston, TX 77052 | Oil & Gas Operator | May 2025 |
| 108 | Daystar Operating Company, LLC | Austin, TX 78750 | Oil & Gas Operator | Apr 2008 |
| 109 | Delta Exploration Company Inc | Denver, CO 80202 | Oil & Gas Operator | May 2025 |
| 110 | Denbury Onshore, LLC | Plano, TX 75024 | Oil & Gas Operator | May 2025 |
| 111 | Devon Energy Operating Corp | Oklahoma City, OK 73102 | Oil & Gas Operator | Apr 2013 |
| 112 | Devon Energy Production Company LP | Oklahoma City, OK 73102 | Oil & Gas Operator | May 2025 |
| 113 | Devon Louisiana Corporation | Houston, TX 77002 | Oil & Gas Operator | Oct 2019 |
| 114 | Diamond S Energy Company | Fort Worth, TX 76132 | Oil & Gas Operator | May 2025 |
| 115 | DJH Investments, Inc. | Houston, TX 77024 | Oil Operator | May 2025 |
| 116 | DKM Resources, Inc. | Tulsa, OK 74136 | Oil & Gas Operator | Sep 2011 |
| 117 | DKW Energy, Inc. | Sherman Oaks, CA 91403 | Oil & Gas Operator | May 2025 |
| 118 | Dominion Oklahoma Texas E&P, Inc | Richmond, VA 23219 | Oil & Gas Operator | Sep 2018 |
| 119 | Douglas Petroleum Inc. | Spring, TX 77379 | Oil & Gas Operator | Nov 2010 |
| 120 | Dreyfus, Louis Natural Gas Corp | Oklahoma City, OK 73134 | Oil & Gas Operator | Nov 2001 |
| 121 | Duncan Energy LLC | Dallas, TX 75231 | Oil & Gas Operator | May 2025 |
| 122 | Dyersdale Energy, L.P. | Kilgore, TX 75663 | Oil & Gas Operator | May 2025 |
| 123 | East Texas Production MGT. Inc | Athens, TX 75751 | Oil & Gas Operator | May 2025 |
| 124 | Eastern Oil Corporation | Houston, TX 77070 | Oil & Gas Operator | May 2025 |
| 125 | Eastex Gas Production Co. | Houston, TX 77042 | Oil & Gas Operator | Aug 1996 |
| 126 | Edwards, Gus Co. | Abilene, TX 79603 | Oil & Gas Operator | Jun 2004 |
| 127 | Eex Corporation | Houston, TX 77060 | Oil & Gas Operator | Feb 2000 |
| 128 | El Paso Field Services Company | Houston, TX 77002 | Oil & Gas Operator | Aug 2003 |
| 129 | Elliott Oil & Gas Company | The Woodlands, TX 77380 | Oil & Gas Operator | Sep 2006 |
| 130 | Elliott Oil & Gas Operating Co. | Magnolia, TX 77354 | Oil & Gas Operator | May 2025 |
| 131 | Ellstrom Energy Company | Kingwood, TX 77339 | Oil & Gas Operator | Nov 2000 |
| 132 | Endeavor Natural Gas, LLC | Houston, TX 77002 | Oil & Gas Operator | Feb 2015 |
| 133 | Enderli Oil Company, Inc | Highlands, TX 77562 | Oil & Gas Operator | Aug 2003 |
| 134 | Energy Development Corporation | Houston, TX 77067 | Oil & Gas Operator | Dec 2024 |
| 135 | Energy Reserves Group LLC | Houston, TX 77002 | Oil & Gas Operator | Mar 2018 |
| 136 | Energy Transfer Crude Marketing LLC | Dallas, TX 75225 | Oil Operator | Jan 2025 |
| 137 | Engroup Resources, L.P. | Houston, TX 77002 | Oil & Gas Operator | May 2025 |
| 138 | Enron Oil & Gas Company | Houston, TX 77210 | Oil & Gas Operator | Dec 1999 |
| 139 | Enserch Exploration Inc | Dallas, TX 75206 | Oil & Gas Operator | Apr 2015 |
| 140 | EOG Resources, Inc. | Midland, TX 79702 | Oil & Gas Operator | May 2025 |
| 141 | Erg Operating Company Inc | Houston, TX 77002 | Oil & Gas Operator | Dec 2006 |
| 142 | Erg Resources LLC | Houston, TX 77002 | Oil & Gas Operator | Oct 2015 |
| 143 | Etc Field Services LLC | San Antonio, TX 78258 | Oil Operator | Jun 2018 |
| 144 | Etoco Incorporated | Houston, TX 77002 | Oil & Gas Operator | May 2005 |
| 145 | Etoco, L.P. | Houston, TX 77002 | Oil & Gas Operator | May 2025 |
| 146 | Evergreen Energy, Inc | Houston, TX 77098 | Oil & Gas Operator | May 2025 |
| 147 | Evolution Resources, LLC | Houston, TX 77070 | Oil & Gas Operator | May 2025 |
| 148 | Exploration Company, The | San Antonio, TX 78258 | Oil & Gas Operator | Jun 2010 |
| 149 | Export Petroleum Corporation | Fort Worth, TX 76147 | Oil & Gas Operator | May 2025 |
| 150 | Exxon Corporation | Houston, TX 77210 | Oil & Gas Operator | Jun 2024 |
| 151 | Exxon Mobil Corporation | Spring, TX 77389 | Oil & Gas Operator | May 2025 |
| 152 | Falcon Oil & Gas Company, Inc. | Houston, TX 77002 | Oil & Gas Operator | Nov 2022 |
| 153 | Famcor Oil, Inc. | Scottsdale, AZ 85260 | Oil & Gas Operator | Sep 2020 |
| 154 | Faulconer Energy, LLC | Tyler, TX 75711 | Oil & Gas Operator | May 2025 |
| 155 | Faulconer Vernon E Inc | Tyler, TX 75711 | Oil & Gas Operator | Mar 2025 |
| 156 | FH Operation Company, Inc. | Dallas, TX 75381 | Oil & Gas Operator | Apr 2005 |
| 157 | Five-Jab, Inc. | Tomball, TX 77377 | Oil & Gas Operator | May 2025 |
| 158 | Flow Energy Inc. | Bellaire, TX 77401 | Oil & Gas Operator | Sep 1996 |
| 159 | Foothills Texas, Inc. | Houston, TX 77269 | Oil & Gas Operator | Aug 2019 |
| 160 | Forest Oil Corporation | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 161 | Forney & McCombs | Houston, TX 77056 | Oil & Gas Operator | Jan 1998 |
| 162 | Fort Worth Natural Gas, Inc. | Dallas, TX 75254 | Oil & Gas Operator | May 2025 |
| 163 | Fortune Natural Resources Corp. | Houston, TX 77067 | Oil & Gas Operator | Dec 2003 |
| 164 | Fortune Operating Company | Willis, TX 77378 | Oil & Gas Operator | May 2025 |
| 165 | Fredonia Resources Inc. | Longview, TX 75606 | Oil & Gas Operator | Aug 2003 |
| 166 | French Production Incorporated | Houston, TX 77086 | Oil & Gas Operator | Dec 1997 |
| 167 | Frio Exploration Company | Pearland, TX 77588 | Oil & Gas Operator | Dec 2000 |
| 168 | Future Petroleum Corporation | Houston, TX 77002 | Oil & Gas Operator | Sep 1999 |
| 169 | G E Operating, Inc. | Graham, TX 76450 | Oil & Gas Operator | May 2020 |
| 170 | Gaither Petroleum Corporation | Katy, TX 77493 | Oil & Gas Operator | May 2025 |
| 171 | Galloway Energy Co. | Tomball, TX 77377 | Oil & Gas Operator | May 2025 |
| 172 | Galloway Lone Star, L.L.C. | Tomball, TX 77377 | Oil & Gas Operator | May 2025 |
| 173 | Gary Oil & Gas | Deer Park, TX 77536 | Oil & Gas Operator | May 2025 |
| 174 | Gei Management Co., Inc. | Houston, TX 77024 | Oil & Gas Operator | Sep 1993 |
| 175 | General Oil Company, Inc. | Wichita, KS 67213 | Oil & Gas Operator | May 2025 |
| 176 | Geo Asset Management, Inc. | Katy, TX 77493 | Oil & Gas Operator | May 2025 |
| 177 | Geo Engineering, Inc. | Houston, TX 77027 | Oil & Gas Operator | Jun 2009 |
| 178 | Geodyne Operating Company | Tulsa, OK 74103 | Oil & Gas Operator | Jun 2015 |
| 179 | Global Natural Resources Corp. | Houston, TX 77002 | Oil & Gas Operator | May 1998 |
| 180 | Goldking Prod. Co. | Houston, TX 77002 | Oil & Gas Operator | Apr 1998 |
| 181 | Goodrich Oil Company | Shreveport, LA 71101 | Oil & Gas Operator | Nov 2001 |
| 182 | Gordy Oil Company | Houston, TX 77007 | Oil & Gas Operator | May 2025 |
| 183 | Gould Oil Inc. | Wichita, KS 67278 | Oil & Gas Operator | Oct 2019 |
| 184 | Grace Petroleum Corp. | Tulsa, OK 74103 | Oil & Gas Operator | Oct 1997 |
| 185 | Graham Royalty LTD | Covington, LA 70434 | Oil & Gas Operator | Jul 2007 |
| 186 | Greenbriar Energy Inc. | Houston, TX 77098 | Oil & Gas Operator | Feb 2004 |
| 187 | Gruy Petroleum Management Co. | Irving, TX 75014 | Oil & Gas Operator | Nov 2014 |
| 188 | GSF Energy, L.L.C. | Pittsburgh, PA 15220 | Gas Operator | Mar 2018 |
| 189 | H.E.R. Operating, LLC | Silsbee, TX 77656 | Oil & Gas Operator | May 2025 |
| 190 | Halcon Operating Co., Inc. | Houston, TX 77024 | Oil & Gas Operator | May 2025 |
| 191 | Hamill, Claud B. Estate Of | Houston, TX 77002 | Oil & Gas Operator | Nov 1995 |
| 192 | Hamman Oil & Refining Company | Houston, TX 77098 | Oil & Gas Operator | May 2025 |
| 193 | Hanson Minerals Co. | Houston, TX 77042 | Oil & Gas Operator | Oct 1993 |
| 194 | Hanson Production Company | Cuero, TX 77954 | Oil & Gas Operator | Jul 2009 |
| 195 | Harrison Interests, LTD. | Houston, TX 77002 | Oil & Gas Operator | May 2025 |
| 196 | Heritage Expl. & Prod. Co., Inc. | Stafford, TX 77497 | Oil & Gas Operator | Dec 2000 |
| 197 | Heritage Operating Co., Inc. The | Stafford, TX 77497 | Oil & Gas Operator | May 1997 |
| 198 | High Bluff Operating, LLC | Littleton, CO 80161 | Oil & Gas Operator | May 2018 |
| 199 | Hilcorp Energy Company | Houston, TX 77208 | Oil & Gas Operator | May 2025 |
| 200 | Hollimon Oil Corporation | Castroville, TX 78009 | Oil & Gas Operator | Nov 2016 |