| 101 | Christa Oil Co | Cumberland, OH 43732 | Oil & Gas Operator | Nov 1999 |
| 102 | Cimarex Energy Co. Of Colorado | Midland, TX 79706 | Oil & Gas Operator | Oct 2025 |
| 103 | Cimarron Operating Company | Oklahoma City, OK 73112-3967 | Oil & Gas Operator | May 2011 |
| 104 | Citrus Energy Corporation | Castle Rock, CO 80104 | Oil & Gas Operator | Mar 2020 |
| 105 | Clydesdale Energy LLC | Oklahoma City, OK 73116-9111 | Oil & Gas Operator | Nov 2019 |
| 106 | CMS Nomeco Oil & Gas Co. | Jackson, MI 49201 | Oil & Gas Operator | Jan 2015 |
| 107 | Co-St Oil Operating Co Inc | Enid, OK 73706 | Oil & Gas Operator | Apr 1997 |
| 108 | Coaleum Corporation | Dallas, TX 75205 | Oil & Gas Operator | Jan 2001 |
| 109 | Coastal Plains Energy Inc | Oklahoma City, OK 73112 | Oil & Gas Operator | Oct 2025 |
| 110 | Coenergy Operating Company | Oklahoma City, OK 73112 | Oil & Gas Operator | Mar 2015 |
| 111 | Colt Resources Corporation | Billings, MT 59103 | Oil & Gas Operator | Feb 2013 |
| 112 | Comanche Exploration Co LLC | Oklahoma City, OK 73116-7334 | Oil & Gas Operator | Jul 2025 |
| 113 | Comanche Petroleum Corporation | Oklahoma City, OK 73179 | Oil & Gas Operator | Apr 2024 |
| 114 | Complete Energy Services LLC | Gainesville, TX 76240 | Oil Operator | Aug 2022 |
| 115 | Concho Exploration Inc | Oklahoma City, OK 73154 | Oil & Gas Operator | Mar 2015 |
| 116 | ConocoPhillips Company | Midland, TX 79701 | Oil & Gas Operator | Oct 2025 |
| 117 | Contango Resources LLC | Andrews, TX 79714 | Oil & Gas Operator | Oct 2025 |
| 118 | Continental Operating Co. | Houston, TX 77024 | Oil & Gas Operator | Oct 2025 |
| 119 | Continental Resources, Inc. | Oklahoma City, OK 73126 | Oil & Gas Operator | Oct 2025 |
| 120 | Cordillera Energy Partners II LLC | Greenwood VIllage, CO 80111-2856 | Oil & Gas Operator | Jun 2025 |
| 121 | Cordillera Energy Partners III LLC | Greenwood VIllage, CO 80111-2856 | Oil & Gas Operator | Mar 2014 |
| 122 | Cordillera Energy Partners LLC | Greenwood VLG, CO 80111 | Oil & Gas Operator | Mar 2020 |
| 123 | Cortez Operating Company | Fort Worth, TX 76102 | Oil & Gas Operator | Nov 2016 |
| 124 | Cory, Kenneth W. | Bellaire, TX 77401 | Oil & Gas Operator | Mar 2012 |
| 125 | Coterra Energy Operating Co. | Midland, TX 79706 | Oil & Gas Operator | Jul 2025 |
| 126 | Cotton Petroleum Corporation | Tulsa, OK 74102 | Oil & Gas Operator | Jan 2005 |
| 127 | Crawley Petroleum Corporation | Oklahoma City, OK 73102 | Oil & Gas Operator | Oct 2025 |
| 128 | Crescendo Resources, L.P. | Amarillo, TX 79188 | Oil & Gas Operator | Jun 2025 |
| 129 | Cross Timbers Operating Co | Fort Worth, TX 76102 | Oil & Gas Operator | Jun 2025 |
| 130 | Crown Energy Company | Oklahoma City, OK 73106 | Oil & Gas Operator | Jun 2025 |
| 131 | Crusader Energy Corporation | Oklahoma City, OK 73102 | Oil & Gas Operator | Sep 2011 |
| 132 | Crusader Energy Group Inc. | Austin, TX 78746 | Oil & Gas Operator | Mar 2015 |
| 133 | Culbreath Oil & Gas Company, Inc. | Tulsa, OK 74135 | Oil & Gas Operator | Jun 2025 |
| 134 | D & D Energy Inc | Sapulpa, OK 74066-8734 | Oil & Gas Operator | May 2013 |
| 135 | D & D Pipe & Equipment Inc | Kingfisher, OK 73750 | Oil & Gas Operator | Mar 2005 |
| 136 | D & J Oil Company | Kermit, TX 79745 | Oil & Gas Operator | Oct 2025 |
| 137 | D C Energy, Inc. | Oklahoma City, OK 73134 | Oil & Gas Operator | Apr 2020 |
| 138 | D.J.F. Services, Inc. | Holdenville, OK 74848 | Oil & Gas Operator | Oct 2025 |
| 139 | Dab Limited | Oklahoma City, OK 73116-9082 | Oil & Gas Operator | Aug 2013 |
| 140 | Dalen Resources Oil & Gas Co. | Dallas, TX 75206 | Oil & Gas Operator | Jun 2010 |
| 141 | Damson Oil Corporation | Houston, TX 77210 | Oil & Gas Operator | Mar 2005 |
| 142 | Davco Productions Inc | Springer, OK 73458-8191 | Oil & Gas Operator | Jun 2021 |
| 143 | Dawson Resources Inc | Franktown, CO 80116 | Oil & Gas Operator | Mar 2015 |
| 144 | DCP Operating Co LP | Houston, TX 77042 | Oil & Gas Operator | May 2025 |
| 145 | Dehart Company (The) | Ardmore, OK 73402 | Oil & Gas Operator | Jul 2025 |
| 146 | Derrick Resources Inc. | Henryetta, OK 74437-4249 | Oil & Gas Operator | Jun 2025 |
| 147 | Dette Oil Corporation | Oklahoma City, OK 73162-6249 | Oil & Gas Operator | Oct 2015 |
| 148 | Devon Energy Corp (Nevada) | Oklahoma City, OK 73102 | Oil & Gas Operator | Feb 2017 |
| 149 | Devon Energy Production Company LP | Oklahoma City, OK 73102 | Oil & Gas Operator | Oct 2025 |
| 150 | Devon Louisiana Corporation | Houston, TX 77002 | Oil & Gas Operator | Oct 2019 |
| 151 | Devon SFS Operating Inc | Oklahoma City, OK 73102 | Oil & Gas Operator | Mar 2008 |
| 152 | Dewey Energy GP LLC | Houston, TX 77002 | Oil & Gas Operator | Jun 2022 |
| 153 | Diamond Harry H Inc | Shawnee, OK 74801 | Oil & Gas Operator | Feb 2025 |
| 154 | Diamond Production Company LLC | Irving, TX 75016-7853 | Oil & Gas Operator | Jun 2025 |
| 155 | Dillingham Ranch LC | Tulsa, OK 74152 | Oil & Gas Operator | May 2013 |
| 156 | Diversified Production LLC | Keithville, LA 71047 | Oil & Gas Operator | Oct 2025 |
| 157 | DLB Oil & Gas, Inc. | Big Lake, TX 76932 | Oil & Gas Operator | Oct 2025 |
| 158 | Dome Petroleum Corp | Denver, CO 80202 | Oil & Gas Operator | Dec 2016 |
| 159 | Dominion Exp Midcontinent Inc | Oklahoma City, OK 73134-2616 | Oil & Gas Operator | Oct 2024 |
| 160 | Dominion Exploration & Production Inc | Houston, TX 77060 | Oil & Gas Operator | Apr 2015 |
| 161 | Dominion Ok TX E & P Inc | Oklahoma City, OK 73134 | Oil & Gas Operator | Nov 2018 |
| 162 | Dorchester Resources LP | Oklahoma City, OK 73154-8879 | Oil & Gas Operator | Aug 2021 |
| 163 | Douglas Fairbanks Holdings LLC | Pine Hurst, TX 77362-9998 | Oil & Gas Operator | Jul 2025 |
| 164 | Duck Bros Dozer & Trucking Inc | Konawa, OK 74849 | Oil & Gas Operator | May 2025 |
| 165 | Duncan Oil Properties, Inc. | Oklahoma City, OK 73102 | Oil & Gas Operator | Oct 2025 |
| 166 | Dyco Petroleum Corporation | Tulsa, OK 74103 | Oil & Gas Operator | Mar 2015 |
| 167 | Eagle Minerals & Oil Prop Inc | Tulsa, OK 74119 | Oil & Gas Operator | Jan 2002 |
| 168 | Eagle Rock Mid-Continent Operating LLC | Tulsa, OK 74103-3703 | Oil & Gas Operator | Jun 2025 |
| 169 | Earlsboro Energies Corporation | Oklahoma City, OK 73116-3605 | Oil & Gas Operator | Jun 2025 |
| 170 | Edinger Engineering, Inc. | Oklahoma City, OK 73102 | Oil & Gas Operator | Jul 2025 |
| 171 | Eec Inc | Norman, OK 73069-6344 | Oil & Gas Operator | Jun 2025 |
| 172 | Ehrlich, Mitchell | Perryton, TX 79070 | Oil & Gas Operator | May 1999 |
| 173 | El Paso Natural Gas Company | El Paso, TX 79978 | Oil & Gas Operator | Apr 2013 |
| 174 | El Paso Production Company | Houston, TX 77002 | Oil & Gas Operator | Mar 2016 |
| 175 | Eland Energy Inc | Dallas, TX 75248 | Oil & Gas Operator | Jul 2025 |
| 176 | Elite Tank Trucks, Inc | | Oil & Gas Operator | Jul 2025 |
| 177 | Elm Ridge Exploration Company LLC | Bloomfield, NM 87413 | Oil & Gas Operator | Nov 2017 |
| 178 | Enable Gas Transmission LLC | Houston, TX 77002 | Oil & Gas Operator | Sep 2022 |
| 179 | Encana Energy Resources Inc | Denver, CO 80202-2828 | Oil & Gas Operator | Feb 2024 |
| 180 | Encino Operating, LLC | Houston, TX 77057 | Oil & Gas Operator | Oct 2025 |
| 181 | Encore Operating LP | Plano, TX 75024 | Oil & Gas Operator | May 2025 |
| 182 | Enernet Inc | Oklahoma City, OK 73102-8004 | Oil & Gas Operator | Nov 2014 |
| 183 | Enerquest Oil & Gas LLC | Oklahoma City, OK 73114 | Oil & Gas Operator | Jun 2025 |
| 184 | Enervest Operating LLC | Houston, TX 77002 | Oil & Gas Operator | Oct 2025 |
| 185 | Enserch Exploration Inc | Dallas, TX 75206 | Oil & Gas Operator | Apr 2015 |
| 186 | EOG (Oklahoma) Inc. | Oklahoma City, OK 73112 | Oil & Gas Operator | Oct 2016 |
| 187 | EOG Resources, Inc. | Midland, TX 79702 | Oil & Gas Operator | Oct 2025 |
| 188 | EP Energy E&P Company, LP | Houston, TX 77210 | Oil & Gas Operator | Jan 2023 |
| 189 | EP Operating LP | Dallas, TX 75201 | Oil & Gas Operator | Mar 2015 |
| 190 | Erwin, James D. | Dallas, TX 75225 | Oil & Gas Operator | Nov 1993 |
| 191 | Esco Exploration, Inc | Dallas, TX 75201 | Oil & Gas Operator | Mar 2015 |
| 192 | Esis Inc | | Oil & Gas Operator | Feb 2017 |
| 193 | Evolution Energy LLC | Oklahoma City, OK 73116 | Oil & Gas Operator | Jul 2025 |
| 194 | Exco Resources Inc | Dallas, TX 75251 | Oil & Gas Operator | Jun 2025 |
| 195 | Exok, Inc. | Oklahoma City, OK 73116 | Oil & Gas Operator | Jun 2025 |
| 196 | Express Oil & Gas LLC | Oklahoma City, OK 73142-3017 | Oil & Gas Operator | Jun 2025 |
| 197 | Exxon Mobil Corporation | Spring, TX 77389 | Oil & Gas Operator | Oct 2025 |
| 198 | Exxonmobil Oil Corp | Houston, TX 77210 | Oil & Gas Operator | Jul 2025 |
| 199 | Fairway Resources Operating III LLC | Houston, TX 77002-2728 | Oil & Gas Operator | Jun 2025 |
| 200 | Fairway Resources Operating, LLC | Southlake, TX 76092 | Oil & Gas Operator | Aug 2022 |