| 4001 | Reserve Partners L.L.C. | | Oil & Gas Operator | Feb 2001 |
| 4002 | Resource Acquisitions Corp. | | Oil & Gas Operator | Dec 2002 |
| 4003 | Resource Development Inc | Stroud, OK 74079 | Oil & Gas Operator | Feb 2007 |
| 4004 | Resource Securities Corp. | | Oil & Gas Operator | Mar 2005 |
| 4005 | Resources America, Inc | | Oil Operator | Jan 1983 |
| 4006 | Resources Investment Corp | Denver, CO 80202 | Oil & Gas Operator | Sep 2018 |
| 4007 | Retsal Drilling Co. | | Oil & Gas Operator | Jan 1984 |
| 4008 | Retsal Production Company | | Oil & Gas Operator | Mar 1986 |
| 4009 | Reunion Energy Company | Houston, TX 77056 | Oil & Gas Operator | May 1996 |
| 4010 | Reunion Resources, Inc. | | Oil & Gas Operator | Dec 2015 |
| 4011 | Reunion Titan, Inc. | | Oil & Gas Operator | Jan 2017 |
| 4012 | Revel Oil & Gas, Inc. | | Oil & Gas Operator | Feb 2001 |
| 4013 | Revilo Exploration, Inc. | Richardson, TX 75081 | Oil & Gas Operator | Jul 2021 |
| 4014 | Reynolds Drill Coinc/Rosbottom | | Oil & Gas Operator | Jan 1990 |
| 4015 | Reynolds Drilling Co., Inc. | Shreveport, LA 71105 | Oil & Gas Operator | Feb 2026 |
| 4016 | Reynolds E & P, Inc. | Shreveport, LA 71105 | Oil & Gas Operator | Feb 2026 |
| 4017 | Reynolds Oil Company | | Oil Operator | Nov 2005 |
| 4018 | Rhoads Oil, LLC | | Oil Operator | Jan 2025 |
| 4019 | Ric Petroleum | | Gas Operator | Dec 1998 |
| 4020 | Riceland Petroleum Company | | Oil & Gas Operator | Nov 2024 |
| 4021 | Richard A. Williams Expl Corp. | | Oil & Gas Operator | Dec 1983 |
| 4022 | Richard B. Nelson,Etal | | Oil & Gas Operator | May 1979 |
| 4023 | Richard C. Hinds | | Oil Operator | Jan 2025 |
| 4024 | Richard H. Lee, L.L.C. | | Oil & Gas Operator | Sep 1999 |
| 4025 | Richard Nelson | | Oil Operator | Feb 1987 |
| 4026 | Richard T. Perry | | Gas Operator | May 1993 |
| 4027 | Richardson Energy Corporation | | Oil & Gas Operator | Dec 1987 |
| 4028 | Ricks & Ricks Oil Producers | | Oil Operator | Sep 1983 |
| 4029 | Ridgelake Energy, Inc. | | Oil & Gas Operator | Jul 2020 |
| 4030 | Ridgeway Exco, Inc. | San Antonio, TX 78279 | Oil & Gas Operator | Mar 1996 |
| 4031 | Rig Iron Petroleum Inc | | Oil & Gas Operator | Aug 1988 |
| 4032 | Rig Iron, Inc. | | Oil & Gas Operator | Mar 1991 |
| 4033 | Rigel Resources Co., Inc. | | Oil Operator | Aug 2009 |
| 4034 | Riley Exploration, LLC | Blanchard, OK 73010 | Oil & Gas Operator | Feb 2026 |
| 4035 | Rimco Production Company, Inc. | | Oil & Gas Operator | Jan 2004 |
| 4036 | Rimfire Swabbing, Inc. | | Oil Operator | Jan 2025 |
| 4037 | Rio Bravo Expl. & Prod. Co. | Houston, TX 77055 | Oil & Gas Operator | Apr 2020 |
| 4038 | Rio Bravo Oil Company | The Woodlands, TX 77381 | Oil & Gas Operator | Feb 2002 |
| 4039 | Rio Grande Drilling Company | San Antonio, TX 78212 | Oil & Gas Operator | Dec 1999 |
| 4040 | Ripco | | Oil & Gas Operator | Jul 1986 |
| 4041 | Rippy Oil Company | Tyler, TX 75702 | Oil & Gas Operator | Feb 2026 |
| 4042 | Riseden Services, Inc. | Houston, TX 77256 | Oil & Gas Operator | Sep 1997 |
| 4043 | Riseden, LTD | | Oil & Gas Operator | Nov 1989 |
| 4044 | Risher Company, Inc. | | Oil & Gas Operator | Jul 2001 |
| 4045 | Rising Star 2000 Oil & Gas, Inc. | | Oil Operator | Dec 2024 |
| 4046 | Rising Star Energy, L.L.C. | Dallas, TX 75219 | Oil & Gas Operator | Aug 2006 |
| 4047 | Rising Star Energy-Oper Co., LLC | | Oil & Gas Operator | Nov 2006 |
| 4048 | River Bend Operating, Inc. | | Oil & Gas Operator | Jul 1999 |
| 4049 | River City Resources, Inc. | Tulsa, OK 74119 | Oil & Gas Operator | Nov 1997 |
| 4050 | River Energy Co., Inc. | | Gas Operator | Dec 2012 |
| 4051 | River Rouge Minerals | | Oil & Gas Operator | Dec 2024 |
| 4052 | River Rouge Minerals Inc | | Oil & Gas Operator | Mar 1981 |
| 4053 | Riverside Resources, Inc. | | Oil & Gas Operator | Oct 2015 |
| 4054 | Riverstone Energy Operating, LLC | Houston, TX 77090 | Oil & Gas Operator | Feb 2026 |
| 4055 | Riverwood Production Co., Inc. | | Oil & Gas Operator | Nov 1990 |
| 4056 | Riviera Operating, LLC | Houston, TX 77002 | Oil & Gas Operator | Dec 2025 |
| 4057 | RLM Energy Company Inc. | Monroe, LA 71201 | Oil & Gas Operator | Mar 2008 |
| 4058 | RLP Gulf States, L.L.C. | | Oil & Gas Operator | Apr 2012 |
| 4059 | RLS Partnership | | Oil Operator | Apr 1983 |
| 4060 | Rme Petroleum Company | Houston, TX 77251 | Oil & Gas Operator | Nov 2016 |
| 4061 | RMR Oil Company | Jacksboro, TX 76458 | Oil & Gas Operator | Sep 2005 |
| 4062 | RMT Resources LLC | | Oil Operator | Jan 2025 |
| 4063 | Robco Investments, Inc. | | Oil & Gas Operator | Jul 2016 |
| 4064 | Roberson Farm Equipment, Inc. | | Oil Operator | Mar 1989 |
| 4065 | Roberson Well Service | | Gas Operator | Dec 2024 |
| 4066 | Robert A Craig | | Oil Operator | Jul 2020 |
| 4067 | Robert C. Pettit | | Oil & Gas Operator | Feb 1986 |
| 4068 | Robert D Valerius Inc. | | Oil Operator | Mar 1996 |
| 4069 | Robert E McDowell | | Oil Operator | Dec 1998 |
| 4070 | Robert G Cox & Assoc La Inc. | | Oil & Gas Operator | Jun 1994 |
| 4071 | Robert K. Freeman | | Oil Operator | Jul 1991 |
| 4072 | Robert L. Waterbury | | Oil & Gas Operator | Nov 2001 |
| 4073 | Robert L. Waterbury, L.L.C. | | Oil & Gas Operator | Dec 2024 |
| 4074 | Robert M. Mills | | Oil Operator | Oct 2017 |
| 4075 | Robert Mosbacher - Harry Hurt | | Oil & Gas Operator | Sep 1978 |
| 4076 | Robert P. Artzberger | | Oil & Gas Operator | Dec 1979 |
| 4077 | Robert S. Barnwell, III | | Oil & Gas Operator | Oct 1984 |
| 4078 | Robert W. Omeara | | Oil & Gas Operator | Sep 1988 |
| 4079 | Roberts & Bunch Resources | | Oil & Gas Operator | Dec 1993 |
| 4080 | Roberts Oil Corp. | | Oil & Gas Operator | Sep 1982 |
| 4081 | Robertson Energy, LLC | | Oil & Gas Operator | Dec 2024 |
| 4082 | Robie A. Bridges III | | Oil Operator | Aug 1993 |
| 4083 | Robinett Resources Inc. | Longview, TX 75601 | Oil & Gas Operator | Dec 1999 |
| 4084 | Roblyn Petroleum Corp. | | Oil & Gas Operator | May 1983 |
| 4085 | Rock Creek Oil, Inc. | Dallas, TX 75225 | Oil & Gas Operator | Nov 2019 |
| 4086 | Rock Energy Operating Company | | Oil & Gas Operator | Nov 2008 |
| 4087 | Rock Energy, Inc. | | Oil & Gas Operator | Sep 1992 |
| 4088 | Rock Well Petroleum (U.S.), Inc. | Canada, 00100 | Oil & Gas Operator | Sep 2014 |
| 4089 | Rockbridge Oil & Gas | Houston, TX 77027 | Oil & Gas Operator | Mar 1990 |
| 4090 | Rockcliff Operating La LLC | | Oil & Gas Operator | Jul 2022 |
| 4091 | Rockland Oil Company | Addison, TX 75001 | Oil & Gas Operator | Nov 2025 |
| 4092 | Rockleigh K. Thurman | | Oil & Gas Operator | Jan 2025 |
| 4093 | Rocky Mount Gas Gathering,LLC | | Oil Operator | Apr 2001 |
| 4094 | Rodessa Operating Company | Corpus Chrsti, TX 78426 | Oil & Gas Operator | Feb 2026 |
| 4095 | Roger Wilson | | Oil Operator | Apr 2002 |
| 4096 | Roger Wilson, Inc. | | Oil Operator | Jul 2019 |
| 4097 | Rogers Oil Co. | Bronson, KS 66716 | Oil & Gas Operator | Sep 1995 |
| 4098 | Rojo Oil Company | McLean, TX 79057 | Oil & Gas Operator | Feb 2026 |
| 4099 | Rollar Oil Co., Inc. | | Oil & Gas Operator | Jul 1999 |
| 4100 | Romaxsco Exploration Co., Inc. | | Oil & Gas Operator | Aug 1993 |