| 101 | Devon Energy Operating Corp | Oklahoma City, OK 73102 | Oil & Gas Operator | Apr 2013 |
| 102 | Devon Energy Production Company LP | Oklahoma City, OK 73102 | Oil & Gas Operator | Jul 2025 |
| 103 | Dietrich Resources Corporation | | Oil & Gas Operator | Jun 2007 |
| 104 | DNR Oil And Gas, Inc. | Englewood, CO 80155 | Oil & Gas Operator | Jun 2025 |
| 105 | Dol Resources Inc | Rowlett, TX 75088 | Oil & Gas Operator | Jun 2025 |
| 106 | Duer Wagner & Company | Fort Worth, TX 76102 | Oil & Gas Operator | Dec 1998 |
| 107 | Dugan Production Corp | Farmington, NM 87499 | Oil & Gas Operator | May 2025 |
| 108 | Duncan Oil Inc | Denver, CO 80210 | Oil & Gas Operator | Jun 2016 |
| 109 | Dyer J G | | Oil & Gas Operator | May 1985 |
| 110 | E & B Natural Resources Management | Guilderland Centek, NY 12085 | Oil & Gas Operator | Apr 2025 |
| 111 | Earthstone Energy, Inc. | The Woodlands, TX 77380 | Oil & Gas Operator | Dec 2017 |
| 112 | Earthstone Operating, LLC | The Woodlands, TX 77380 | Oil & Gas Operator | May 2025 |
| 113 | Eason Oil Company | Oklahoma City, OK 73112 | Oil & Gas Operator | Mar 2012 |
| 114 | Eberspecher Drilling Inc | Casper, WY 82601 | Oil & Gas Operator | Dec 2000 |
| 115 | Eex Corporation | Houston, TX 77060 | Oil & Gas Operator | Feb 2000 |
| 116 | Eland Energy Inc | Dallas, TX 75248 | Oil & Gas Operator | May 2025 |
| 117 | Elephant Operating LLC | Dallas, TX 75204 | Oil & Gas Operator | May 2025 |
| 118 | Ellbogen John P LTD | Casper, WY 82602 | Oil & Gas Operator | Jun 2025 |
| 119 | Endeavor Energy Resources, LP | Midland, TX 79701 | Oil & Gas Operator | Jul 2025 |
| 120 | Energas Corporation | Oklahoma City, OK 73105 | Oil & Gas Operator | Feb 2025 |
| 121 | Energetics Inc | Englewood, CO 80155 | Oil & Gas Operator | Aug 1985 |
| 122 | Energy Search Company Inc | Aurora, CO 80011 | Oil & Gas Operator | Jun 2021 |
| 123 | Enpro LLC | Cottonwood, UT 84047 | Oil & Gas Operator | Nov 2017 |
| 124 | Envirosearch Corporation | | Oil Operator | Dec 1992 |
| 125 | EOG Resources, Inc. | Midland, TX 79702 | Oil & Gas Operator | Jul 2025 |
| 126 | EOG Y Resources Inc | Artesia, NM 88210 | Oil & Gas Operator | Feb 2019 |
| 127 | EP Energy E&P Company, LP | Houston, TX 77210 | Oil & Gas Operator | Jan 2023 |
| 128 | Equitable Resources Energy Company | Big Stone Gap, VA 24219 | Oil & Gas Operator | Dec 1997 |
| 129 | Evergreen Operating Company | Denver, CO 80202 | Oil & Gas Operator | Apr 1996 |
| 130 | Exco Resources Inc | Dallas, TX 75251 | Oil & Gas Operator | Apr 2025 |
| 131 | Exeter Drilling Company | Denver, CO 80217 | Oil & Gas Operator | Sep 1997 |
| 132 | Exxon Mobil Corporation | Spring, TX 77389 | Oil & Gas Operator | Jul 2025 |
| 133 | Exxonmobil Oil Corp | Houston, TX 77210 | Oil & Gas Operator | May 2025 |
| 134 | Felmont Oil Corporation | Walnut Creek, CA 94596-3568 | Oil & Gas Operator | Feb 1990 |
| 135 | Ferguson & Bosworth | | Oil & Gas Operator | May 2007 |
| 136 | Fina Oil And Chemical Company | Dallas, TX 75221 | Oil & Gas Operator | May 2019 |
| 137 | Finley Resources Inc | Fort Worth, TX 76113 | Oil & Gas Operator | Jul 2025 |
| 138 | Flag-Redfern Oil Company | Oklahoma City, OK 73125 | Oil & Gas Operator | Jul 2002 |
| 139 | Flahive Oil & Gas LLC | Golden, CO 80401 | Oil Operator | Oct 1995 |
| 140 | Flying J Oil & Gas Inc | North Salt Lake, UT 84054 | Oil & Gas Operator | Dec 2009 |
| 141 | Forcenergy Inc | Miami, FL 33129 | Oil & Gas Operator | Mar 2015 |
| 142 | Forestar Petroleum Corporation | Denver, CO 80202 | Oil & Gas Operator | May 2017 |
| 143 | Fossil Creek Resources LLC | Arlington, TX 76011-5597 | Oil & Gas Operator | Mar 2015 |
| 144 | Frickey Investment MGT Co LLC | Lakewood, CO 80215 | Oil & Gas Operator | May 2025 |
| 145 | General American Oil Co Of Texas | | Oil & Gas Operator | Mar 1983 |
| 146 | General Atlantic Resources Inc | Denver, CO 80202 | Oil & Gas Operator | Jan 2022 |
| 147 | General Crude Oil Co | Houston, TX 77005 | Oil & Gas Operator | Dec 1979 |
| 148 | Genesis Production Company | | Oil & Gas Operator | May 1991 |
| 149 | Getty Oil Company | Hays, KS 67601 | Oil & Gas Operator | Mar 2015 |
| 150 | Gibson J W | | Oil & Gas Operator | Sep 1999 |
| 151 | GLG Energy LP | Austin, TX 78701 | Oil & Gas Operator | Jun 1994 |
| 152 | Goodstein Fred | Casper, WY 82602 | Oil & Gas Operator | Mar 1984 |
| 153 | Graham Royalty LTD | Covington, LA 70434 | Oil & Gas Operator | Jul 2007 |
| 154 | Grayling Resources LTD | Lakewood, CO 80235 | Oil & Gas Operator | Jul 2020 |
| 155 | Grayson Mill Operating LLC | Houston, TX 77024 | Oil & Gas Operator | May 2025 |
| 156 | Great Northern Drilling Company | Billings, MT 59103 | Oil & Gas Operator | Jun 2016 |
| 157 | Great Western Drilling Co | Midland, TX 79701 | Oil & Gas Operator | Jul 2025 |
| 158 | Great Western Oil Company | | Oil & Gas Operator | Dec 1984 |
| 159 | Gross Todd | Pine Bluffs, WY 82082 | Oil & Gas Operator | Mar 2007 |
| 160 | Grynberg, Jack J. | Denver, CO 80237 | Oil & Gas Operator | Jun 2021 |
| 161 | Gulf Exploration, LLC | Oklahoma City, OK 73114 | Oil & Gas Operator | Jun 2025 |
| 162 | Gulf Oil Corp. | Denver, CO 80201-0599 | Oil & Gas Operator | Dec 2014 |
| 163 | Gulf Production Corporation | Oklahoma City, OK 73114 | Oil & Gas Operator | Apr 2015 |
| 164 | H & M Oil Producers | Littleton, CO 80160 | Oil & Gas Operator | Apr 2000 |
| 165 | H & R Well Services, Inc. | FT Morgan, CO 80701 | Oil & Gas Operator | Apr 2015 |
| 166 | Hallador Petroleum LLP | Denver, CO 80264 | Oil & Gas Operator | Feb 2019 |
| 167 | Harpel John P Jr | FT. Collins, CO 80525 | Oil & Gas Operator | May 1998 |
| 168 | Hawks Company | Casper, WY 82602 | Oil & Gas Operator | Apr 2007 |
| 169 | Headington Oil Company, L.P. | Dallas, TX 75231 | Oil & Gas Operator | Mar 2008 |
| 170 | Hedges Spencer | Casper, WY 82604 | Oil Operator | Mar 2024 |
| 171 | Helis Oil & Gas Company LLC Estate | New Orleans, LA 70130 | Oil & Gas Operator | Jul 2022 |
| 172 | Henderson Petroleum Corp | San Angelo, TX 76906 | Oil & Gas Operator | Jul 2013 |
| 173 | Hi-Pro Production | Gillette, WY 82717 | Gas Operator | Nov 2003 |
| 174 | Home Petroleum Corp | Victoria, TX 77902 | Oil & Gas Operator | Jul 2025 |
| 175 | Hondo Oil & Gas | Houston, TX 77042 | Oil & Gas Operator | Oct 1995 |
| 176 | Houston Oil And Minerals | | Oil & Gas Operator | Oct 1993 |
| 177 | Hyperion Oil & Gas LLC | Dallas, TX 75251 | Oil & Gas Operator | Jul 2025 |
| 178 | Impact Exploration & Production LLC | Greenwood VIllage, CO 80111 | Oil & Gas Operator | May 2025 |
| 179 | Independent Production Company | Greenwood VIllage, CO 80121 | Oil & Gas Operator | May 2003 |
| 180 | Inexco Oil Company | Houston, TX 77210 | Oil & Gas Operator | Mar 2013 |
| 181 | Integrated Energy Inc | Houston, TX 77002 | Oil & Gas Operator | Aug 2003 |
| 182 | Integrity Oil & Gas | Golden, CO 80401 | Oil & Gas Operator | May 2011 |
| 183 | Interline Resources Corp | Casper, WY 82601 | Oil & Gas Operator | Oct 2009 |
| 184 | Internorth Inc | Tulsa, OK 74136 | Oil & Gas Operator | Apr 2014 |
| 185 | Intoil, Inc. | Englewood, CO 80155 | Oil & Gas Operator | Dec 2002 |
| 186 | Itr Petroleum Inc | Houston, TX 77002 | Oil & Gas Operator | Apr 1998 |
| 187 | Jetta Operating Company Inc | Fort Worth, TX 76102 | Oil & Gas Operator | Jul 2025 |
| 188 | Jims Water Service Inc | Gillette, WY 82717 | Oil & Gas Operator | Oct 2016 |
| 189 | JN Exploration & Production | Billings, MT 59103-0159 | Oil & Gas Operator | Apr 2001 |
| 190 | Joemar Wyoming Operating LLC | | Oil & Gas Operator | May 2025 |
| 191 | JT Operating LLC | Douglas, WY 82633 | Oil & Gas Operator | May 2025 |
| 192 | Justice Oil & Gas LLC | Gillette, WY 82716 | Oil & Gas Operator | May 2025 |
| 193 | K N Energy Inc | Lakewood, CO 80228 | Oil & Gas Operator | Nov 2000 |
| 194 | Kachina Exploration Inc | Cheyenne, WY 82003 | Oil & Gas Operator | Jul 2000 |
| 195 | Kaiser-Francis Oil Company | Tulsa, OK 74121 | Oil & Gas Operator | Jul 2025 |
| 196 | Keiths Pumping Service | Douglas, WY 82633 | Oil & Gas Operator | Aug 2003 |
| 197 | Kenai Oil & Gas Inc | | Oil & Gas Operator | Jun 1987 |
| 198 | Kennedy Oil | Gillette, WY 82716 | Oil & Gas Operator | May 2025 |
| 199 | Kerr-McGee Corporation | Dallas, TX 75380 | Oil & Gas Operator | Apr 2025 |
| 200 | Kerr-McGee Oil & Gas Onshore LP | Houston, TX 77046 | Oil & Gas Operator | Jul 2025 |