| 101 | Crimson Exploration Inc. | Houston, TX 77060 | Oil & Gas Operator | Apr 2006 |
| 102 | Crimson Exploration Oper., Inc. | Houston, TX 77002 | Oil & Gas Operator | Dec 2019 |
| 103 | Crossroads Petroleum L.L.C. | San Benito, TX 78586 | Oil & Gas Operator | Jul 2025 |
| 104 | Crystal Oil Company | Shreveport, LA 71120 | Oil & Gas Operator | Jul 1995 |
| 105 | Cummins & Walker Oil Co., Inc. | Austin, TX 78746 | Oil & Gas Operator | Jan 2021 |
| 106 | Cymri Corporation, The | Houston, TX 77057 | Oil & Gas Operator | Mar 2008 |
| 107 | Cymri, L.L.C. | Houston, TX 77042 | Oil & Gas Operator | Jul 2025 |
| 108 | D&H-S-S Production Co.,Inc | Corpus Chrsti, TX 78409 | Oil & Gas Operator | Aug 2003 |
| 109 | D&M Operating, L.L.C. | Corpus Chrsti, TX 78414 | Gas Operator | Jul 2025 |
| 110 | D.Y. Exploration, Inc. | Boise, ID 83705 | Oil & Gas Operator | Jul 2025 |
| 111 | Dale Operating Company | Dallas, TX 75201 | Oil & Gas Operator | Jul 2025 |
| 112 | Dale Operations, LLC | Dickinson, TX 77539 | Oil & Gas Operator | Jul 2025 |
| 113 | Dark Horse Producing Of TX, L.P. | Alice, TX 78333 | Oil & Gas Operator | Jul 2025 |
| 114 | DCP Operating Co LP | Houston, TX 77042 | Oil & Gas Operator | Apr 2025 |
| 115 | Devon Energy Production Company LP | Oklahoma City, OK 73102 | Oil & Gas Operator | Jul 2025 |
| 116 | Devon Louisiana Corporation | Houston, TX 77002 | Oil & Gas Operator | Oct 2019 |
| 117 | Dewbre Petroleum Corporation | Corpus Chrsti, TX 78404 | Oil & Gas Operator | Jul 2025 |
| 118 | Diamond "S" Oil, Inc. | Houston, TX 77065 | Oil & Gas Operator | Apr 1994 |
| 119 | Dinero Oil Corporation | Corpus Chrsti, TX 78460 | Oil & Gas Operator | Nov 1999 |
| 120 | Dinero Operating Co | Midland, TX 79702 | Oil & Gas Operator | Jul 2025 |
| 121 | Discorbis Oil Company | San Antonio, TX 78217 | Oil & Gas Operator | Jul 2019 |
| 122 | Discovery Energy Corp. CC | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Jul 2025 |
| 123 | Discovery Petroleum, L.L.C. | Alice, TX 78333 | Oil & Gas Operator | Jul 2025 |
| 124 | Dolphin Petroleum | Alice, TX 78333 | Oil & Gas Operator | Jun 2008 |
| 125 | Dolphin Petroleum, LP | Alice, TX 78333 | Oil & Gas Operator | Jul 2025 |
| 126 | Dorado Oil Company | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Oct 2013 |
| 127 | Double Play Oil & Gas, Inc | Portland, TX 78374 | Oil & Gas Operator | Jul 2025 |
| 128 | Dugger, Glenn | Alice, TX 78332 | Oil & Gas Operator | Nov 2013 |
| 129 | Durst Oil Company | Corpus Chrsti, TX 78477 | Oil & Gas Operator | Sep 2000 |
| 130 | Duster Production, Inc. | Refugio, TX 78377 | Oil & Gas Operator | Oct 2011 |
| 131 | Duval Gas Gathering Corporation | Austin, TX 78711 | Oil & Gas Operator | Jul 2025 |
| 132 | Dynamic Petroleum Res., Inc. | Houston, TX 77068 | Oil & Gas Operator | Jul 1994 |
| 133 | E.G.L. Resources, Inc. | Midland, TX 79702 | Oil & Gas Operator | Apr 2025 |
| 134 | Eagle Oil & Gas Co. | Dallas, TX 75225 | Oil & Gas Operator | Jul 2025 |
| 135 | Egan Resources Inc. | Katy, TX 77494 | Oil & Gas Operator | Oct 2016 |
| 136 | El Dorado Resources Inc. | Waco, TX 76710 | Oil & Gas Operator | Oct 2009 |
| 137 | El Paso Production Oil & Gas Co. | Houston, TX 77252 | Oil & Gas Operator | Jul 2025 |
| 138 | Ellsworth, H. P. O&G Properties | Corpus Chrsti, TX 78413 | Oil & Gas Operator | Jul 2025 |
| 139 | Emerald Oil & Gas LC | Fort Worth, TX 76109 | Oil & Gas Operator | Jul 2025 |
| 140 | Encino Exploration, Inc. | George West, TX 78022 | Oil & Gas Operator | Jul 2025 |
| 141 | Enco Exploration Company | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Apr 2020 |
| 142 | Endeavor Natural Gas, LP | Houston, TX 77002 | Oil & Gas Operator | Jul 2025 |
| 143 | Endeavor Production Company | San Angelo, TX 76904 | Oil & Gas Operator | Mar 2008 |
| 144 | Enerfin Field Services LLC | Houston, TX 77077 | Oil Operator | Nov 2024 |
| 145 | Enerquest Operating, LLC | Oklahoma City, OK 73114 | Oil & Gas Operator | Jul 2025 |
| 146 | Engelke, R. H. | San Antonio, TX 78230 | Oil & Gas Operator | Jul 2025 |
| 147 | Enron Oil & Gas Company | Houston, TX 77210 | Oil & Gas Operator | Dec 1999 |
| 148 | EOG Resources, Inc. | Midland, TX 79702 | Oil & Gas Operator | Jul 2025 |
| 149 | Esenjay Petroleum Corp. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Jul 1998 |
| 150 | Everest Resource Company | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Jul 2025 |
| 151 | Exp, Inc. | Dallas, TX 75244 | Oil & Gas Operator | May 2003 |
| 152 | Exxcel Operating Company | San Antonio, TX 78227 | Oil & Gas Operator | Jul 2025 |
| 153 | Exxon Corporation | Houston, TX 77210 | Oil & Gas Operator | Jun 2024 |
| 154 | Exxon Mobil Corporation | Spring, TX 77389 | Oil & Gas Operator | Jul 2025 |
| 155 | Fair Operating, Inc. | Boerne, TX 78015 | Oil & Gas Operator | Jul 2025 |
| 156 | Faulconer Energy, LLC | Tyler, TX 75711 | Oil & Gas Operator | Jul 2025 |
| 157 | Faulconer Vernon E Inc | Tyler, TX 75711 | Oil & Gas Operator | May 2025 |
| 158 | Fina Oil And Chemical Company | Dallas, TX 75221 | Oil & Gas Operator | May 2019 |
| 159 | Finaly Resources LLC | Sunset Beach, CA 90742 | Oil & Gas Operator | Jul 2025 |
| 160 | Flare Oil Inc | Rockport, TX 78382 | Oil & Gas Operator | Jul 2025 |
| 161 | Flournoy Production Co. | Alice, TX 78333 | Oil & Gas Operator | Dec 2002 |
| 162 | Forest Oil Corporation | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 163 | Forney & McCombs | Houston, TX 77056 | Oil & Gas Operator | Jan 1998 |
| 164 | Fox, Hewitt B., Inc. | Corpus Chrsti, TX 78411 | Oil & Gas Operator | Jul 2025 |
| 165 | Fredco | Louise, TX 77455 | Oil & Gas Operator | Jul 2025 |
| 166 | Freedom Energy, Inc. (I) | Horseshoe Bay, TX 78657 | Oil & Gas Operator | Jun 2003 |
| 167 | Freedom Energy, LTD. | Horseshoe Bay, TX 78657 | Oil & Gas Operator | Jun 2011 |
| 168 | Freeman Expl. & Prod. Co., Inc. | Houston, TX 77279 | Oil & Gas Operator | Aug 2020 |
| 169 | Fuller Petroleum Inc | Midland, TX 79702 | Oil & Gas Operator | Mar 2008 |
| 170 | Gaither Petroleum Corporation | Katy, TX 77493 | Oil & Gas Operator | Jul 2025 |
| 171 | Galindo Brothers, Inc. | Alice, TX 78333 | Oil & Gas Operator | Jul 2025 |
| 172 | Garza, Sergio R. | Orange Grove, TX 78372 | Oil Operator | Jul 2025 |
| 173 | Gasper Rice Resources, LTD. | Houston, TX 77068 | Oil & Gas Operator | Jul 2025 |
| 174 | Geiser, D. Allen | Portland, TX 78374 | Oil & Gas Operator | Oct 2005 |
| 175 | Genesis Producing Company | Houston, TX 77024 | Oil & Gas Operator | Oct 2007 |
| 176 | Geodominion Petroleum | Corpus Chrsti, TX 78403 | Oil & Gas Operator | May 2012 |
| 177 | Geodyne Operating Company | Tulsa, OK 74103 | Oil & Gas Operator | Jun 2015 |
| 178 | Geomeg Energy Operating Co., LLC | Aransas Pass, TX 78336 | Oil & Gas Operator | Jul 2025 |
| 179 | Goldking Prod. Co. | Houston, TX 77002 | Oil & Gas Operator | Apr 1998 |
| 180 | Goliad Operating Company | Houston, TX 77265 | Oil & Gas Operator | Aug 2003 |
| 181 | Grace Petroleum Corp. | Tulsa, OK 74103 | Oil & Gas Operator | Oct 1997 |
| 182 | Graham Royalty LTD | Covington, LA 70434 | Oil & Gas Operator | Jul 2007 |
| 183 | Grand Operating, Inc. | Addison, TX 75001 | Oil & Gas Operator | Dec 2020 |
| 184 | Great Texas Crude Inc. | Fredericksbrg, TX 78624 | Oil & Gas Operator | Jul 2025 |
| 185 | Green Exploration Company | Austin, TX 78711 | Oil & Gas Operator | Jul 2025 |
| 186 | Guinn Operating Company | Spring Branch, TX 78070 | Oil & Gas Operator | Feb 2014 |
| 187 | Guinn Operating Company, LLC | San Antonio, TX 78260 | Oil Operator | Jul 2025 |
| 188 | H & P Exploration Co. | Alice, TX 78333 | Oil & Gas Operator | May 2019 |
| 189 | Haigood, Danny | Portland, TX 78374 | Oil & Gas Operator | Mar 2008 |
| 190 | Hamilton Brothers Oil Co. | Houston, TX 77057 | Oil & Gas Operator | Mar 2015 |
| 191 | Hamman Oil & Refining Company | Houston, TX 77098 | Oil & Gas Operator | Jul 2025 |
| 192 | Haring Energy Company | Tuleta, TX 78162 | Oil & Gas Operator | Mar 2003 |
| 193 | Harper Hefte, Inc. | Corpus Chrsti, TX 78410 | Oil & Gas Operator | Jul 2025 |
| 194 | Harris Energy Services, LLC | Dallas, TX 75201 | Oil & Gas Operator | Jul 2025 |
| 195 | Harwood Exploration, Inc. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Aug 1995 |
| 196 | Hawn Brothers | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Apr 2003 |
| 197 | Hayes Oil & Gas Co. | Fort Worth, TX 76102 | Oil & Gas Operator | Mar 2005 |
| 198 | Headwaters Energy Partners, LLC | Dripping SPGS, TX 78620 | Oil & Gas Operator | Jul 2025 |
| 199 | Hilcorp Energy Company | Houston, TX 77208 | Oil & Gas Operator | Jul 2025 |
| 200 | Houston Exploration Co, The | Houston, TX 77002 | Oil & Gas Operator | Apr 2017 |