| 901 | Rebel Oil Company | Keaton, KY 41226 | Oil & Gas Operator | Jan 2025 |
| 902 | Rebel Production Company | Kilgore, TX 75663 | Oil Operator | May 2026 |
| 903 | Red River Oil & Gas Inc. | | Oil & Gas Operator | May 2012 |
| 904 | Red Rock Production L.L.C. | | Oil Operator | Jan 2025 |
| 905 | Regal Petroleum Services, Inc. | Euless, TX 76039-1127 | Oil & Gas Operator | May 2015 |
| 906 | Regency Field Services LLC | Dallas, TX 75201 | Oil Operator | Jul 2017 |
| 907 | Regency Gas Gathrng & Proc LLC | | Oil Operator | Sep 2007 |
| 908 | Regency Intrastate Gas LLC | | Oil Operator | Feb 2009 |
| 909 | Reliant Energy Field SVS Inc. | | Oil Operator | Sep 2002 |
| 910 | Relmm Corporation | | Oil & Gas Operator | May 1980 |
| 911 | Republic Energy Resources,Inc. | | Oil Operator | May 1991 |
| 912 | Republic Gas Gathering Sys Inc | | Oil & Gas Operator | Nov 1981 |
| 913 | Resources America, Inc | | Oil Operator | Jan 1983 |
| 914 | Revel Oil & Gas, Inc. | | Oil & Gas Operator | Feb 2001 |
| 915 | Rhoads Oil, LLC | | Oil Operator | Jan 2025 |
| 916 | Rising Star Energy, L.L.C. | Dallas, TX 75219 | Oil & Gas Operator | Aug 2006 |
| 917 | Rising Star Energy-Oper Co., LLC | | Oil & Gas Operator | Nov 2006 |
| 918 | Riverside Resources, Inc. | | Oil & Gas Operator | Oct 2015 |
| 919 | Riverstone Energy Operating, LLC | Houston, TX 77090 | Oil & Gas Operator | May 2026 |
| 920 | RMT Resources LLC | | Oil Operator | Jan 2025 |
| 921 | Robco Investments, Inc. | | Oil & Gas Operator | Jul 2016 |
| 922 | Robert E McDowell | | Oil Operator | Dec 1998 |
| 923 | Robert G Cox & Assoc La Inc. | | Oil & Gas Operator | Jun 1994 |
| 924 | Robert M. Mills | | Oil Operator | Oct 2017 |
| 925 | Robert S. Barnwell, III | | Oil & Gas Operator | Oct 1984 |
| 926 | Roberts Oil Corp. | | Oil & Gas Operator | Sep 1982 |
| 927 | Robie A. Bridges III | | Oil Operator | Aug 1993 |
| 928 | Rock Well Petroleum (U.S.), Inc. | Canada, 00100 | Oil & Gas Operator | Sep 2014 |
| 929 | Rodessa Operating Company | Corpus Chrsti, TX 78426 | Oil & Gas Operator | May 2026 |
| 930 | Rogers Oil Co. | Bronson, KS 66716 | Oil & Gas Operator | Sep 1995 |
| 931 | Ronald E. Hall | | Oil Operator | Nov 1991 |
| 932 | Ronny N. Davis | | Oil Operator | Jan 2025 |
| 933 | Rooster Production, LLC | Oil City, LA 71061 | Oil Operator | Jan 2025 |
| 934 | Rosbottom Petroleum | | Oil & Gas Operator | Aug 1988 |
| 935 | Rosbottom Production Corp | Shreveport, LA 71134 | Oil & Gas Operator | Dec 2017 |
| 936 | Rose Pass Mines, Inc. | | Oil Operator | Oct 1982 |
| 937 | Ross & Glenn Petroleum Inc. | | Oil & Gas Operator | Aug 1984 |
| 938 | Ross Exploration,Inc. | Fort Worth, TX 76102 | Oil & Gas Operator | Jul 2013 |
| 939 | Ross Production Co. | Shreveport, LA 71101 | Oil & Gas Operator | Mar 2000 |
| 940 | Rowe Oil Co. | | Oil Operator | Jan 2002 |
| 941 | Roy D. Gish | | Oil & Gas Operator | Sep 2019 |
| 942 | Royal Petroleum Corp. | Dallas, TX 75229 | Oil & Gas Operator | Jan 2025 |
| 943 | S. G. Myers, Jr. | | Oil & Gas Operator | May 2005 |
| 944 | Sabine Pipe & Supply Co. | Kilgore, TX 75663 | Oil & Gas Operator | Sep 2004 |
| 945 | Sabine Pipe, Inc. | Kilgore, TX 75663 | Oil & Gas Operator | May 2026 |
| 946 | Sahara Gas & Exploration, Inc. | | Gas Operator | Mar 2002 |
| 947 | Sally Oil Company | | Oil Operator | Sep 2016 |
| 948 | Sam R. Brown | | Oil Operator | Mar 1987 |
| 949 | Samedan Oil Corporation | Houston, TX 77067 | Oil & Gas Operator | Dec 2019 |
| 950 | Sammy D. Thrash | | Oil & Gas Operator | May 2012 |
| 951 | Sammy D. Thrash, LLC | | Oil & Gas Operator | May 2019 |
| 952 | Sample Exploration | | Oil & Gas Operator | Jul 2002 |
| 953 | Samson Contour Energy E&P, LLC | Tulsa, OK 74103 | Oil & Gas Operator | Sep 2017 |
| 954 | San Miguel Oil & Gas, Inc. | | Oil & Gas Operator | Jan 1993 |
| 955 | Sawyer Drilling & Service Inc. | | Oil & Gas Operator | Oct 2004 |
| 956 | Sayes Drilling Inc. | | Oil Operator | May 1987 |
| 957 | Scogin Exploration Inc | | Oil & Gas Operator | Dec 1999 |
| 958 | Scott W. Brumley | | Oil Operator | Apr 2011 |
| 959 | SDG Services LLC | Kilgore, TX 75663 | Oil Operator | Sep 2025 |
| 960 | Seagull Energy E & P Inc | Houston, TX 77002 | Oil & Gas Operator | Jan 2015 |
| 961 | Seagull Mid-South Inc | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 962 | Seagull Operating Co., Inc. | Shreveport, LA 71101 | Oil & Gas Operator | Jan 2025 |
| 963 | Sendero Energy Inc. | Dallas, TX 75205 | Oil & Gas Operator | May 2026 |
| 964 | Ses Production | | Oil & Gas Operator | Oct 2023 |
| 965 | SG Interests, Inc. | Houston, TX 77010 | Oil & Gas Operator | Jun 2007 |
| 966 | Shelby Operating Company | Dallas, TX 75205 | Oil & Gas Operator | May 2026 |
| 967 | Shoco Production, L.P. | Kilgore, TX 75663 | Oil & Gas Operator | May 2020 |
| 968 | Shoreline Southeast LLC | | Oil & Gas Operator | Jun 2017 |
| 969 | SHS Operating Company | Shreveport, LA 71149 | Oil & Gas Operator | Jan 2025 |
| 970 | Shufflin Energy | | Oil & Gas Operator | Sep 2011 |
| 971 | Sigma Energy, LLC | | Oil Operator | Jan 2025 |
| 972 | Silver Hill Energy Operating, LLC | Dallas, TX 75201 | Oil & Gas Operator | May 2026 |
| 973 | Skinner Energy Management, Inc. | Shreveport, LA 71135 | Oil & Gas Operator | Jan 2011 |
| 974 | Sklar & Phillips Oil Co. | Shreveport, LA 71101 | Oil & Gas Operator | Dec 2000 |
| 975 | Sklar Exploration Company LLC | Shreveport, LA 71101 | Oil & Gas Operator | May 2026 |
| 976 | Smith Operating And MGMT Co. | Shreveport, LA 71161 | Oil & Gas Operator | Jun 2023 |
| 977 | SND Operating, L.L.C. | Kilgore, TX 75663 | Oil & Gas Operator | May 2026 |
| 978 | Solid Rock Prod. | | Oil Operator | Nov 1994 |
| 979 | Sonat Exploration Co. | Houston, TX 77251 | Oil & Gas Operator | Dec 2021 |
| 980 | Source Petroleum Inc. | San Antonio, TX 78265 | Oil & Gas Operator | May 2026 |
| 981 | South Central Petroleum, Inc. | | Oil & Gas Operator | Dec 1988 |
| 982 | Southern Oil & Gas Company | | Oil & Gas Operator | Mar 2011 |
| 983 | Southern States Gas & Oil LTD | | Oil & Gas Operator | Jul 2004 |
| 984 | Southern States Oil Production, LLC | | Oil & Gas Operator | Oct 2013 |
| 985 | Southwest Operating Inc. | | Oil & Gas Operator | Dec 2024 |
| 986 | Southwestern Electric Power Co | Dallas, TX 75266 | Oil & Gas Operator | Dec 1989 |
| 987 | Sovereign Energy Corp. | | Oil Operator | Dec 2001 |
| 988 | Spicy Daugx Operators Louisiana LLC | | Oil & Gas Operator | Nov 2024 |
| 989 | Spyglass Oil & Gas LLC | | Oil & Gas Operator | Dec 2024 |
| 990 | St. Mary Land & Exploration Co | Denver, CO 80201 | Oil & Gas Operator | Jun 2010 |
| 991 | Standard Production | | Oil Operator | Oct 1997 |
| 992 | Star Falcon Oil Co. | | Oil Operator | Feb 1986 |
| 993 | Stewart Oil Co. | | Oil Operator | Jun 2009 |
| 994 | Stinhall Corporation | | Oil & Gas Operator | Apr 1989 |
| 995 | Stratco Operating Co Inc | Austin, TX 78701 | Oil & Gas Operator | May 2026 |
| 996 | Stroud Operating LLC | | Oil & Gas Operator | Dec 2012 |
| 997 | Stroud Petroleum, Inc. | Shreveport, LA 71162 | Oil & Gas Operator | May 2026 |
| 998 | Stroud Production LLC | Shreveport, LA 71101 | Oil & Gas Operator | Dec 2024 |
| 999 | Stuart Oil | | Oil Operator | Jan 2025 |
| 1000 | Studley Resources Corporation | Humble, TX 77347 | Oil & Gas Operator | Dec 1996 |