| 101 | Red Willow Offshore, LLC | | Oil & Gas Operator | Apr 2011 |
| 102 | Red Wing Oil & Gas, Inc. | | Oil Operator | Sep 1990 |
| 103 | Redd Production Of Mansfield | | Oil & Gas Operator | Jan 1991 |
| 104 | Redman Operating Company | Houston, TX 77042 | Oil & Gas Operator | May 2008 |
| 105 | Redmon Oil Company, Inc., The | Plano, TX 75023 | Oil & Gas Operator | Jun 2025 |
| 106 | Reeder Production | | Oil Operator | Oct 2005 |
| 107 | Reef Exploration Inc | Denver, CO 80202 | Oil & Gas Operator | Feb 2007 |
| 108 | Reef Exploration, L.P. | Richardson, TX 75080 | Oil & Gas Operator | Jun 2025 |
| 109 | Reese Energy Corp. | | Oil & Gas Operator | Oct 1991 |
| 110 | Reese Oil & Gas LTD | | Oil & Gas Operator | Sep 1991 |
| 111 | Reese Oil And Gas Company | | Oil & Gas Operator | Mar 1985 |
| 112 | Refined Products, Inc. | Beaumont, TX 77705 | Oil Operator | Jun 2025 |
| 113 | Regal Petroleum Services Inc | Euless, TX 76039-1127 | Oil & Gas Operator | May 2015 |
| 114 | Regency Field Services LLC | Dallas, TX 75201 | Oil Operator | Jul 2017 |
| 115 | Regency Gas Gathrng & Proc LLC | | Oil Operator | Sep 2007 |
| 116 | Regency Intrastate Gas LLC | | Oil Operator | Feb 2009 |
| 117 | Reita Oil Company | | Oil & Gas Operator | Jan 1987 |
| 118 | Relco Exploration Co., Inc. | | Gas Operator | Aug 1987 |
| 119 | Reliable Prod Service Inc. | | Oil Operator | Mar 2007 |
| 120 | Reliance Energy, L.L.C. | | Oil & Gas Operator | Dec 2024 |
| 121 | Reliance Petroleum Corporation | | Oil & Gas Operator | Oct 2018 |
| 122 | Reliance TR-JV | | Gas Operator | Apr 1988 |
| 123 | Reliance Trusts | Dallas, TX 75244 | Oil & Gas Operator | Nov 1995 |
| 124 | Reliance Trusts HS | | Gas Operator | Feb 1989 |
| 125 | Reliance Well Service, Inc. | | Oil & Gas Operator | Apr 1997 |
| 126 | Reliant Energy Field SVS Inc. | | Oil Operator | Sep 2002 |
| 127 | Relmm Corporation | | Oil & Gas Operator | May 1980 |
| 128 | Relmm CSC/Imc | | Oil & Gas Operator | Apr 1977 |
| 129 | Remuda Oil & Gas Corp. | | Oil & Gas Operator | Aug 1987 |
| 130 | Remuda Operating Company | Midland, TX 79711 | Oil & Gas Operator | Jun 2025 |
| 131 | Renaissance Offshore, LLC | | Oil & Gas Operator | Mar 2023 |
| 132 | Renaissance Petroleum Co LLC | Houston, TX 77058 | Oil & Gas Operator | Nov 2011 |
| 133 | Rental & Fishing Tools, Inc. | | Oil Operator | Dec 2024 |
| 134 | Republic Energy Resources,Inc. | | Oil Operator | May 1991 |
| 135 | Republic Gas Gathering Sys Inc | | Oil & Gas Operator | Nov 1981 |
| 136 | Republic Mineral Corporation | | Oil & Gas Operator | Sep 1987 |
| 137 | Republic Petroleum Corp. | | Oil & Gas Operator | Nov 1977 |
| 138 | Republic Prod.Co.Of Tex., Inc | | Oil & Gas Operator | Jun 1981 |
| 139 | Research Enterprises, Inc. | | Oil Operator | Jan 1996 |
| 140 | Reserve Oil Inc. | | Oil & Gas Operator | Jan 1980 |
| 141 | Reserve Partners L.L.C. | | Oil & Gas Operator | Feb 2001 |
| 142 | Resource Acquisitions Corp. | | Oil & Gas Operator | Dec 2002 |
| 143 | Resource Development, Inc. | Stroud, OK 74079 | Oil & Gas Operator | Feb 2007 |
| 144 | Resource Securities Corp. | | Oil & Gas Operator | Mar 2005 |
| 145 | Resources America, Inc | | Oil Operator | Jan 1983 |
| 146 | Resources Investment Corp | Denver, CO 80202 | Oil & Gas Operator | Sep 2018 |
| 147 | Retsal Drilling Co. | | Oil & Gas Operator | Jan 1984 |
| 148 | Retsal Production Company | | Oil & Gas Operator | Mar 1986 |
| 149 | Reunion Energy Company | Houston, TX 77056 | Oil & Gas Operator | May 1996 |
| 150 | Reunion Resources, Inc. | | Oil & Gas Operator | Dec 2015 |
| 151 | Reunion Titan, Inc. | | Oil & Gas Operator | Jan 2017 |
| 152 | Revel Oil & Gas, Inc. | | Oil & Gas Operator | Feb 2001 |
| 153 | Revilo Exploration, Inc. | Richardson, TX 75081 | Oil & Gas Operator | Jul 2021 |
| 154 | Reynolds Drill Coinc/Rosbottom | | Oil & Gas Operator | Jan 1990 |
| 155 | Reynolds Drilling Co., Inc. | Shreveport, LA 71105 | Oil & Gas Operator | Jun 2025 |
| 156 | Reynolds E & P, Inc. | Shreveport, LA 71105 | Oil & Gas Operator | Jun 2025 |
| 157 | Reynolds Oil Co. | | Oil Operator | Nov 2005 |
| 158 | Rhoads Oil, LLC | | Oil Operator | Jan 2025 |
| 159 | Ric Petroleum | | Gas Operator | Dec 1998 |
| 160 | Riceland Petroleum Company | | Oil & Gas Operator | Nov 2024 |
| 161 | Richard A. Williams Expl Corp. | | Oil & Gas Operator | Dec 1983 |
| 162 | Richard B. Nelson,Etal | | Oil & Gas Operator | May 1979 |
| 163 | Richard C. Hinds | | Oil Operator | Jan 2025 |
| 164 | Richard H. Lee, L.L.C. | | Oil & Gas Operator | Sep 1999 |
| 165 | Richard Nelson | | Oil Operator | Feb 1987 |
| 166 | Richard T. Perry | | Gas Operator | May 1993 |
| 167 | Richardson Energy Corporation | | Oil & Gas Operator | Dec 1987 |
| 168 | Ricks & Ricks Oil Producers | | Oil Operator | Sep 1983 |
| 169 | Ridgelake Energy, Inc. | | Oil & Gas Operator | Jul 2020 |
| 170 | Ridgeway Exco, Inc. | San Antonio, TX 78279 | Oil & Gas Operator | Mar 1996 |
| 171 | Rig Iron Petroleum Inc | | Oil & Gas Operator | Aug 1988 |
| 172 | Rig Iron, Inc. | | Oil & Gas Operator | Mar 1991 |
| 173 | Rigel Resources Co., Inc. | | Oil Operator | Aug 2009 |
| 174 | Riley Exploration, LLC | Blanchard, OK 73010 | Oil & Gas Operator | Jun 2025 |
| 175 | Rimco Production Company, Inc. | | Oil & Gas Operator | Jan 2004 |
| 176 | Rimfire Swabbing, Inc. | | Oil Operator | Jan 2025 |
| 177 | Rio Bravo Expl. & Prod. Co. | Houston, TX 77055 | Oil & Gas Operator | Apr 2020 |
| 178 | Rio Bravo Oil Company | The Woodlands, TX 77381 | Oil & Gas Operator | Feb 2002 |
| 179 | Rio Grande Drilling Company | San Antonio, TX 78212 | Oil & Gas Operator | Dec 1999 |
| 180 | Ripco | | Oil & Gas Operator | Jul 1986 |
| 181 | Rippy Oil Company | Tyler, TX 75702 | Oil & Gas Operator | Jun 2025 |
| 182 | Riseden Services, Inc. | Houston, TX 77256 | Oil & Gas Operator | Sep 1997 |
| 183 | Riseden, LTD | | Oil & Gas Operator | Nov 1989 |
| 184 | Risher Company, Inc. | | Oil & Gas Operator | Jul 2001 |
| 185 | Rising Star 2000 Oil & Gas, Inc. | | Oil Operator | Dec 2024 |
| 186 | Rising Star Energy, L.L.C. | Dallas, TX 75219 | Oil & Gas Operator | Aug 2006 |
| 187 | Rising Star Energy-Oper Co., LLC | | Oil & Gas Operator | Nov 2006 |
| 188 | River Bend Operating, Inc. | | Oil & Gas Operator | Jul 1999 |
| 189 | River City Resources Inc | Tulsa, OK 74119 | Oil & Gas Operator | Nov 1997 |
| 190 | River Energy Co., Inc. | | Gas Operator | Dec 2012 |
| 191 | River Rouge Minerals | | Oil & Gas Operator | Dec 2024 |
| 192 | River Rouge Minerals Inc | | Oil & Gas Operator | Mar 1981 |
| 193 | Riverside Resources, Inc. | | Oil & Gas Operator | Oct 2015 |
| 194 | Riverstone Energy Operating, LLC | Houston, TX 77090 | Oil & Gas Operator | Jun 2025 |
| 195 | Riverwood Production Co., Inc. | | Oil & Gas Operator | Nov 1990 |
| 196 | Riviera Operating, LLC | Houston, TX 77002 | Oil & Gas Operator | Mar 2025 |
| 197 | RLM Energy Company Inc. | Monroe, LA 71201 | Oil & Gas Operator | Mar 2008 |
| 198 | RLP Gulf States, L.L.C. | | Oil & Gas Operator | Apr 2012 |
| 199 | RLS Partnership | | Oil Operator | Apr 1983 |
| 200 | Rme Petroleum Company | Houston, TX 77251 | Oil & Gas Operator | Nov 2016 |