| 3901 | Reunion Energy Company | Houston, TX 77056 | Oil & Gas Operator | May 1996 |
| 3902 | Reunion Resources, Inc. | | Oil & Gas Operator | Dec 2015 |
| 3903 | Reunion Titan, Inc. | | Oil & Gas Operator | Jan 2017 |
| 3904 | Revel Oil & Gas, Inc. | | Oil & Gas Operator | Feb 2001 |
| 3905 | Revilo Exploration, Inc. | Richardson, TX 75081 | Oil & Gas Operator | Jul 2021 |
| 3906 | Reynolds Drill Coinc/Rosbottom | | Oil & Gas Operator | Jan 1990 |
| 3907 | Reynolds Drilling Co., Inc. | Shreveport, LA 71105 | Oil & Gas Operator | May 2025 |
| 3908 | Reynolds E & P, Inc. | Shreveport, LA 71105 | Oil & Gas Operator | May 2025 |
| 3909 | Reynolds Oil Co. | | Oil Operator | Nov 2005 |
| 3910 | Rhoads Oil, LLC | | Oil Operator | Jan 2025 |
| 3911 | Ric Petroleum | | Gas Operator | Dec 1998 |
| 3912 | Riceland Petroleum Company | | Oil & Gas Operator | Nov 2024 |
| 3913 | Richard A. Williams Expl Corp. | | Oil & Gas Operator | Dec 1983 |
| 3914 | Richard B. Nelson,Etal | | Oil & Gas Operator | May 1979 |
| 3915 | Richard C. Hinds | | Oil Operator | Jan 2025 |
| 3916 | Richard H. Lee, L.L.C. | | Oil & Gas Operator | Sep 1999 |
| 3917 | Richard Nelson | | Oil Operator | Feb 1987 |
| 3918 | Richard T. Perry | | Gas Operator | May 1993 |
| 3919 | Richardson Energy Corporation | | Oil & Gas Operator | Dec 1987 |
| 3920 | Ricks & Ricks Oil Producers | | Oil Operator | Sep 1983 |
| 3921 | Ridgelake Energy, Inc. | | Oil & Gas Operator | Jul 2020 |
| 3922 | Ridgeway Exco, Inc. | San Antonio, TX 78279 | Oil & Gas Operator | Mar 1996 |
| 3923 | Rig Iron Petroleum Inc | | Oil & Gas Operator | Aug 1988 |
| 3924 | Rig Iron, Inc. | | Oil & Gas Operator | Mar 1991 |
| 3925 | Rigel Resources Co., Inc. | | Oil Operator | Aug 2009 |
| 3926 | Riley Exploration, LLC | Blanchard, OK 73010 | Oil & Gas Operator | May 2025 |
| 3927 | Rimco Production Company, Inc. | | Oil & Gas Operator | Jan 2004 |
| 3928 | Rimfire Swabbing, Inc. | | Oil Operator | Jan 2025 |
| 3929 | Rio Bravo Expl. & Prod. Co. | Houston, TX 77055 | Oil & Gas Operator | Apr 2020 |
| 3930 | Rio Bravo Oil Company | The Woodlands, TX 77381 | Oil & Gas Operator | Feb 2002 |
| 3931 | Rio Grande Drilling Company | San Antonio, TX 78212 | Oil & Gas Operator | Dec 1999 |
| 3932 | Ripco | | Oil & Gas Operator | Jul 1986 |
| 3933 | Rippy Oil Company | Tyler, TX 75702 | Oil & Gas Operator | May 2025 |
| 3934 | Riseden Services, Inc. | Houston, TX 77256 | Oil & Gas Operator | Sep 1997 |
| 3935 | Riseden, LTD | | Oil & Gas Operator | Nov 1989 |
| 3936 | Risher Company, Inc. | | Oil & Gas Operator | Jul 2001 |
| 3937 | Rising Star 2000 Oil & Gas, Inc. | | Oil Operator | Dec 2024 |
| 3938 | Rising Star Energy, L.L.C. | Dallas, TX 75219 | Oil & Gas Operator | Aug 2006 |
| 3939 | Rising Star Energy-Oper Co., LLC | | Oil & Gas Operator | Nov 2006 |
| 3940 | River Bend Operating, Inc. | | Oil & Gas Operator | Jul 1999 |
| 3941 | River City Resources, Inc. | Tulsa, OK 74119 | Oil & Gas Operator | Nov 1997 |
| 3942 | River Energy Co., Inc. | | Gas Operator | Dec 2012 |
| 3943 | River Rouge Minerals | | Oil & Gas Operator | Dec 2024 |
| 3944 | River Rouge Minerals Inc | | Oil & Gas Operator | Mar 1981 |
| 3945 | Riverside Resources, Inc. | | Oil & Gas Operator | Oct 2015 |
| 3946 | Riverstone Energy Operating, LLC | Houston, TX 77090 | Oil & Gas Operator | May 2025 |
| 3947 | Riverwood Production Co., Inc. | | Oil & Gas Operator | Nov 1990 |
| 3948 | Riviera Operating, LLC | Houston, TX 77002 | Oil & Gas Operator | Mar 2025 |
| 3949 | RLM Energy Company Inc. | Monroe, LA 71201 | Oil & Gas Operator | Mar 2008 |
| 3950 | RLP Gulf States, L.L.C. | | Oil & Gas Operator | Apr 2012 |
| 3951 | RLS Partnership | | Oil Operator | Apr 1983 |
| 3952 | Rme Petroleum Company | Houston, TX 77251 | Oil & Gas Operator | Nov 2016 |
| 3953 | RMR Oil Company | Jacksboro, TX 76458 | Oil & Gas Operator | Sep 2005 |
| 3954 | RMT Resources LLC | | Oil Operator | Jan 2025 |
| 3955 | Robco Investments, Inc. | | Oil & Gas Operator | Jul 2016 |
| 3956 | Roberson Farm Equipment, Inc. | | Oil Operator | Mar 1989 |
| 3957 | Roberson Well Service | | Gas Operator | Dec 2024 |
| 3958 | Robert A Craig | | Oil Operator | Jul 2020 |
| 3959 | Robert C. Pettit | | Oil & Gas Operator | Feb 1986 |
| 3960 | Robert D Valerius Inc. | | Oil Operator | Mar 1996 |
| 3961 | Robert E McDowell | | Oil Operator | Dec 1998 |
| 3962 | Robert G Cox & Assoc La Inc. | | Oil & Gas Operator | Jun 1994 |
| 3963 | Robert K. Freeman | | Oil Operator | Jul 1991 |
| 3964 | Robert L. Waterbury | | Oil & Gas Operator | Nov 2001 |
| 3965 | Robert L. Waterbury, L.L.C. | | Oil & Gas Operator | Dec 2024 |
| 3966 | Robert M. Mills | | Oil Operator | Oct 2017 |
| 3967 | Robert P. Artzberger | | Oil & Gas Operator | Dec 1979 |
| 3968 | Robert S. Barnwell, III | | Oil & Gas Operator | Oct 1984 |
| 3969 | Robert W. Omeara | | Oil & Gas Operator | Sep 1988 |
| 3970 | Roberts & Bunch Resources | | Oil & Gas Operator | Dec 1993 |
| 3971 | Roberts Oil Corp. | | Oil & Gas Operator | Sep 1982 |
| 3972 | Robertson Energy, LLC | | Oil & Gas Operator | Dec 2024 |
| 3973 | Robie A. Bridges III | | Oil Operator | Aug 1993 |
| 3974 | Robinett Resources Inc. | Longview, TX 75601 | Oil & Gas Operator | Dec 1999 |
| 3975 | Roblyn Petroleum Corp. | | Oil & Gas Operator | May 1983 |
| 3976 | Rock Creek Oil, Inc. | Dallas, TX 75225 | Oil & Gas Operator | Nov 2019 |
| 3977 | Rock Energy Operating Company | | Oil & Gas Operator | Nov 2008 |
| 3978 | Rock Energy, Inc. | | Oil & Gas Operator | Sep 1992 |
| 3979 | Rock Well Petroleum (U.S.), Inc. | Canada, 00100 | Oil & Gas Operator | Sep 2014 |
| 3980 | Rockbridge Oil & Gas | Houston, TX 77027 | Oil & Gas Operator | Mar 1990 |
| 3981 | Rockcliff Operating La LLC | | Oil & Gas Operator | Jul 2022 |
| 3982 | Rockland Oil Company | Addison, TX 75001 | Oil & Gas Operator | Feb 2025 |
| 3983 | Rockleigh K. Thurman | | Oil & Gas Operator | Jan 2025 |
| 3984 | Rocky Mount Gas Gathering,LLC | | Oil Operator | Apr 2001 |
| 3985 | Rodessa Operating Company | Corpus Chrsti, TX 78426 | Oil & Gas Operator | May 2025 |
| 3986 | Roger Wilson | | Oil Operator | Apr 2002 |
| 3987 | Roger Wilson, Inc. | | Oil Operator | Jul 2019 |
| 3988 | Rogers Oil Co. | Bronson, KS 66716 | Oil & Gas Operator | Sep 1995 |
| 3989 | Rojo Oil Company | McLean, TX 79057 | Oil & Gas Operator | May 2025 |
| 3990 | Rollar Oil Co., Inc. | | Oil & Gas Operator | Jul 1999 |
| 3991 | Romaxsco Exploration Co., Inc. | | Oil & Gas Operator | Aug 1993 |
| 3992 | Roms Co., Inc. | | Oil Operator | Jun 1983 |
| 3993 | Ron Knott & Associates,Inc. | | Oil & Gas Operator | Aug 1989 |
| 3994 | Ronald E. Hall | | Oil Operator | Nov 1991 |
| 3995 | Ronny N. Davis | | Oil Operator | Jan 2025 |
| 3996 | Rooster Petroleum, LLC | | Oil & Gas Operator | Feb 2011 |
| 3997 | Rooster Production, LLC | Oil City, LA 71061 | Oil Operator | Jan 2025 |
| 3998 | Roppolo Petro/Sun Explor& Prod | | Oil & Gas Operator | Sep 1988 |
| 3999 | Rosamond Drilling Co., Inc. | | Gas Operator | Nov 1984 |
| 4000 | Rosbottom Petroleum | | Oil & Gas Operator | Aug 1988 |