| 11901 | Union Crude Company | Baytown, TX 77521 | Oil & Gas Operator | Apr 2018 |
| 11902 | Union Crude Operating Co. | Baytown, TX 77521 | Oil Operator | Aug 2003 |
| 11903 | Union Gas Operating Company | Spring, TX 77391 | Oil & Gas Operator | Feb 2026 |
| 11904 | Union Oil Co Of California | Midland, TX 79706 | Oil & Gas Operator | Jan 2022 |
| 11905 | Union Pacific Austin Chalk Co. | Fort Worth, TX 76101 | Oil & Gas Operator | Jan 2001 |
| 11906 | Union Pacific Resources Co. | Fort Worth, TX 76101 | Oil & Gas Operator | Jan 2001 |
| 11907 | Union Royalty, Inc. | Midland, TX 79706 | Oil & Gas Operator | Jul 2014 |
| 11908 | Union Seaboard Corporation | Houston, TX 77024 | Oil & Gas Operator | Mar 2008 |
| 11909 | Unit Petroleum Company | Tulsa, OK 74170 | Oil & Gas Operator | Feb 2026 |
| 11910 | United Company | Lubbock, TX 79408 | Oil & Gas Operator | Jun 1995 |
| 11911 | United Energy Corporation | San Antonio, TX 78209 | Oil & Gas Operator | Feb 2026 |
| 11912 | United Energy Operating, LLC | Edmond, OK 73083 | Oil & Gas Operator | Feb 2026 |
| 11913 | United Energy Partners, Inc. | Dallas, TX 75201 | Oil & Gas Operator | Mar 2008 |
| 11914 | United Oil & Minerals L. P. | Austin, TX 78746 | Oil & Gas Operator | Jun 2003 |
| 11915 | United Oil & Minerals, Inc. | Austin, TX 78746 | Oil & Gas Operator | Jan 2001 |
| 11916 | United Oil & Shale LLC | Woodward, OK 73801 | Oil & Gas Operator | Feb 2026 |
| 11917 | United Operating Company | Olney, TX 76374 | Oil & Gas Operator | Aug 2003 |
| 11918 | United Operating, LLC *** | Midland, TX 79710 | Oil & Gas Operator | Feb 2026 |
| 11919 | United Petroleum & Gas, Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Feb 2026 |
| 11920 | United Petroleum Technologies | Hondo, TX 78861 | Oil & Gas Operator | Aug 2001 |
| 11921 | United Resources LP | Austin, TX 78746 | Oil & Gas Operator | Oct 2011 |
| 11922 | United States Gypsum Company | Oakfield, NY 14125 | Oil & Gas Operator | Dec 2024 |
| 11923 | United Texas Oil LLC | Houston, TX 77027 | Oil & Gas Operator | Feb 2026 |
| 11924 | United Texas Petroleum Inc. | McKinney, TX 75070 | Oil & Gas Operator | Feb 2026 |
| 11925 | United World Energy, Inc. | Aurora, CO 80040 | Oil & Gas Operator | Feb 2026 |
| 11926 | Unitex Oil & Gas, L.L.C. | Midland, TX 79701 | Oil & Gas Operator | Feb 2026 |
| 11927 | Universal Geopower LLC | Houston, TX 77057 | Oil & Gas Operator | May 2016 |
| 11928 | Universal Petroleum Corporation | Houston, TX 77002 | Oil & Gas Operator | Sep 2002 |
| 11929 | Universal Resources Corp. | Salt Lake Cty, UT 84145 | Oil & Gas Operator | Jan 2000 |
| 11930 | Unknown | Houston, TX 77208 | Oil & Gas Operator | Dec 2023 |
| 11931 | Unocal Exploration Corporation | Houston, TX 77001 | Oil & Gas Operator | May 1992 |
| 11932 | Unoco, Inc. | Kerrville, TX 78029 | Oil & Gas Operator | Jan 1999 |
| 11933 | Unoso Operating Company L.L.C. | Georgetown, TX 78633 | Oil & Gas Operator | Feb 2026 |
| 11934 | Unswept Oil Company | Corsicana, TX 75151 | Oil & Gas Operator | Jan 2018 |
| 11935 | Untamed Resources, LLC | Spearman, TX 79081 | Gas Operator | Feb 2026 |
| 11936 | Uosi Operating, Inc. | Lovelady, TX 75851 | Oil & Gas Operator | Feb 2026 |
| 11937 | Upco | Mineral Wells, TX 76068 | Gas Operator | Sep 2001 |
| 11938 | Upcurve Energy, LLC | Houston, TX 77024 | Oil & Gas Operator | Feb 2026 |
| 11939 | Upda Operators, Inc. | Jacksboro, TX 76458 | Oil & Gas Operator | Dec 2009 |
| 11940 | Upham Oil & Gas Company | Mineral Wells, TX 76068 | Oil & Gas Operator | Feb 2026 |
| 11941 | Upham, Chester R., Jr. | Mineral Wells, TX 76067 | Oil & Gas Operator | Aug 2001 |
| 11942 | Uphill Consulting LLC | Pearland, TX 77584 | Oil & Gas Operator | Feb 2026 |
| 11943 | Upland Exploration, LLC | Boerne, TX 78006 | Oil & Gas Operator | Jul 2024 |
| 11944 | Upland Operating, LLC | Dallas, TX 75226 | Oil & Gas Operator | Feb 2026 |
| 11945 | Upland Production Company | Edmond, OK 73083 | Oil & Gas Operator | Feb 2026 |
| 11946 | Upland Resources LLC | Canadian, TX 79014 | Oil & Gas Operator | Feb 2026 |
| 11947 | Upland Resources, Inc. | Canadian, TX 79014 | Oil & Gas Operator | Dec 2009 |
| 11948 | Uplands Resources Inc | Tulsa, OK 74103-4141 | Oil & Gas Operator | Nov 2025 |
| 11949 | Uplift Production Company, Inc. | Shamrock, TX 79079 | Oil & Gas Operator | Feb 1999 |
| 11950 | Upp Operating, LLC | Houston, TX 77002 | Oil & Gas Operator | Feb 2026 |
| 11951 | Upstream Exploration LLC | Metairie, LA 70002 | Oil & Gas Operator | Jan 2020 |
| 11952 | Upstream Properties, LLC | Southlake, TX 76092 | Oil & Gas Operator | Feb 2026 |
| 11953 | Upstream Resource Partners, LLC | Elkhart, TX 75839 | Oil Operator | Feb 2026 |
| 11954 | Uptex Operating Inc. | Dallas, TX 75201 | Oil & Gas Operator | May 2011 |
| 11955 | Uptex Operating, L.P. | Dallas, TX 75201 | Oil & Gas Operator | May 2010 |
| 11956 | Urban Oil & Gas Group, LLC | Plano, TX 75074 | Oil & Gas Operator | Feb 2026 |
| 11957 | Ursa Operating Company LLC | Denver, CO 80265 | Oil & Gas Operator | Feb 2014 |
| 11958 | Ursus Oil And Gas | Tyler, TX 75703 | Oil & Gas Operator | Feb 2026 |
| 11959 | Us Ecology Winnie, LLC | Winnie, TX 77665 | Oil Operator | Feb 2026 |
| 11960 | Us Energy Corp. | Houston, TX 77057 | Oil & Gas Operator | Dec 2021 |
| 11961 | Us Energy Holdings, LLC | Richardson, TX 75080 | Oil & Gas Operator | Feb 2026 |
| 11962 | Us Petro LP | Amarillo, TX 79106 | Oil & Gas Operator | Apr 2020 |
| 11963 | Us. Fuels, Inc. | Breckenridge, TX 76424 | Oil & Gas Operator | Feb 2026 |
| 11964 | USA Superior Energy LLC | Houston, TX 77077 | Oil Operator | Mar 2010 |
| 11965 | USA Tubulars, Inc. | Valley Spring, TX 76885 | Oil & Gas Operator | Dec 1995 |
| 11966 | Usfg Oil & Gas, Inc. | Dallas, TX 75231 | Oil & Gas Operator | Dec 2005 |
| 11967 | Utility Ventures Company | Pasadena, TX 77504 | Oil & Gas Operator | Feb 2026 |
| 11968 | Utoco, LTD. | Midland, TX 79704 | Oil Operator | Feb 2026 |
| 11969 | Uvalde Energy Co. | Austin, TX 78747 | Oil & Gas Operator | Nov 1994 |
| 11970 | V & H Oil, L.P. | Muenster, TX 76252 | Oil & Gas Operator | Feb 2026 |
| 11971 | V S Oil Company | Burkburnett, TX 76354 | Oil & Gas Operator | Feb 2026 |
| 11972 | V-F Petroleum Inc. | Midland, TX 79702 | Oil & Gas Operator | Feb 2026 |
| 11973 | V/J Oil Company | Yancey, TX 78886 | Oil & Gas Operator | Oct 2015 |
| 11974 | Vaalco Energy (USA), Inc. | Houston, TX 77042 | Oil & Gas Operator | Dec 2016 |
| 11975 | Vac-U-Lift Production Co.,Inc. | Lake Forest, CA 92630 | Oil & Gas Operator | Feb 2026 |
| 11976 | Vaca Operating Company LLC | Pacific PLSDS, CA 90272 | Oil & Gas Operator | Aug 2017 |
| 11977 | Vale Petroleum Corporation | Houston, TX 77042 | Gas Operator | Jan 1995 |
| 11978 | Valence Operating Company | Kingwood, TX 77339 | Oil & Gas Operator | Feb 2026 |
| 11979 | Valentine Oil & Gas, L.C. | Carmine, TX 78932 | Oil Operator | Nov 2018 |
| 11980 | Valera Oil Company | Kingsland, TX 78639 | Oil & Gas Operator | Apr 2000 |
| 11981 | Valerius, Inc. & Zine, Inc. | Corpus Chrsti, TX 78473 | Oil & Gas Operator | Jul 1994 |
| 11982 | Valerius, Robert D. Inc. | Corpus Chrsti, TX 78473 | Oil & Gas Operator | Aug 2003 |
| 11983 | Validus Energy II Midcon LLC | Denver, CO 80202 | Oil & Gas Operator | Feb 2026 |
| 11984 | Validus NRG Aquilas Assetco LLC | Denver, CO 80202 | Oil & Gas Operator | Nov 2022 |
| 11985 | Validus Operating Inc. | Port Aransas, TX 78373 | Oil & Gas Operator | Oct 1998 |
| 11986 | Valla Energy Corporation | Odessa, TX 79762 | Oil & Gas Operator | Aug 2003 |
| 11987 | Valley Gathering Company | Midland, TX 79702 | Oil & Gas Operator | Feb 1997 |
| 11988 | Valley Petrochemicals, LLC | Pharr, TX 78577 | Oil Operator | Feb 2026 |
| 11989 | Valley Petroleum Company | Abilene, TX 79608 | Oil & Gas Operator | Feb 2026 |
| 11990 | Valley Resources, Inc. | Abilene, TX 79608 | Oil & Gas Operator | Aug 2003 |
| 11991 | Valor Energy, LLC | Dallas, TX 75205 | Oil & Gas Operator | May 2023 |
| 11992 | Valpoint Operating, LLC | Amarillo, TX 79101 | Oil & Gas Operator | Feb 2026 |
| 11993 | Vamos Oil & Gas, LLC | Miami, FL 33129 | Oil & Gas Operator | Feb 2026 |
| 11994 | Van Oil Co Inc | Fort Worth, TX 76116 | Oil Operator | Dec 1997 |
| 11995 | Van Operating, LTD. | Albany, TX 76430 | Oil & Gas Operator | Feb 2026 |
| 11996 | Van Tol Oil | Sanger, TX 76266 | Oil & Gas Operator | Feb 2026 |
| 11997 | Van Winkle Oil | Floresville, TX 78114 | Oil & Gas Operator | Feb 2026 |
| 11998 | Vanco Oil & Gas Corp. | Abilene, TX 79604 | Oil & Gas Operator | Feb 2026 |
| 11999 | Vandermeer Energy Corp. | Dallas, TX 75225 | Oil & Gas Operator | Nov 1998 |
| 12000 | Vandeveer Energy, LLC | Dallas, TX 75225 | Oil & Gas Operator | Jul 2016 |