| 1 | U Bee Tea Production LLC | Culbertson, MT 59218 | Oil & Gas Operator | Mar 2025 |
| 2 | U R C C | | Oil & Gas Operator | Jun 1991 |
| 3 | U S Department Of Energy | | Oil & Gas Operator | Apr 1999 |
| 4 | U S Drilling Company Inc | Holdenville, OK 74848-0913 | Oil & Gas Operator | Mar 2017 |
| 5 | U S Energy Corp. Of Amer. Inc. | Ranger, TX 76470 | Oil & Gas Operator | May 2025 |
| 6 | U S Exploraton Liq Trust | | Oil & Gas Operator | Oct 1994 |
| 7 | U S Liquids Of La., L.P. | | Oil Operator | Apr 2014 |
| 8 | U V Industries | | Oil & Gas Operator | Jan 1993 |
| 9 | U-N-I Exploratio | | Oil & Gas Operator | Dec 1990 |
| 10 | U-N-I Exploration & Development, Inc. | Yates Center, KS 66783 | Oil & Gas Operator | Jan 2003 |
| 11 | U. D. Man, Inc. | San Antonio, TX 78212 | Oil & Gas Operator | May 2025 |
| 12 | U. O. C., Inc. | | Oil Operator | Jun 2019 |
| 13 | U. S. Operating, Inc. | Dallas, TX 75252 | Oil & Gas Operator | May 2025 |
| 14 | U.S. Capital Corp Of Am, Inc. | | Oil & Gas Operator | Aug 1998 |
| 15 | U.S. Enercorp, LLC | San Antonio, TX 78217 | Oil & Gas Operator | Jul 2004 |
| 16 | U.S. Enercorp, LTD. | San Antonio, TX 78209 | Oil & Gas Operator | Sep 2019 |
| 17 | U.S. Energy Development Corp | Fort Worth, TX 76164 | Oil & Gas Operator | May 2025 |
| 18 | U.S. Exploration Company | Houston, TX 77002 | Oil & Gas Operator | Aug 2003 |
| 19 | U.S. Oil Reclaimers, LLC | | Oil Operator | Jun 2023 |
| 20 | U.S. Sovereign Oil And Gas, Inc. | Dallas, TX 75355 | Oil & Gas Operator | May 2025 |
| 21 | U.S. Steel Mining Co., Inc. | | Gas Operator | Jan 2000 |
| 22 | U.S. Steel Mining Co., LLC | | Gas Operator | Oct 2002 |
| 23 | U.S.A. Plugging Company | Pearsall, TX 78061 | Oil & Gas Operator | May 2025 |
| 24 | U1 Ranch Oil | Houston, TX 77269 | Oil & Gas Operator | May 2025 |
| 25 | Uae Investco 1 (Estill), LLC | Ravenna, KY 40472 | Oil Operator | Dec 2022 |
| 26 | Uae Investco 2 (Lee), LLC | Ravenna, KY 40472 | Oil Operator | Dec 2021 |
| 27 | Ubetco, Inc. | Rockdale, TX 76567 | Oil & Gas Operator | May 2025 |
| 28 | Uebelhor, Theodore | | Oil Operator | Dec 2023 |
| 29 | Uehlin LLC | Oberlin, KS 67749 | Oil Operator | Dec 2024 |
| 30 | Uhc New Mexico Corporation | Midland, TX 79702 | Oil & Gas Operator | Feb 2007 |
| 31 | Uhc Petroleum Corporation | Rocksprings, TX 78880 | Oil & Gas Operator | May 2025 |
| 32 | Uhl Oil Co., Inc. | Bradford, PA 16701 | Oil & Gas Operator | Dec 2023 |
| 33 | Uhl, Robert | Bradford, PA 16701 | Oil & Gas Operator | Dec 2023 |
| 34 | Uhls, Jimmie J. | Sedan, KS 67361 | Oil Operator | Sep 2019 |
| 35 | Uinta Oil & Gas | Roosevelt, UT 84066 | Oil & Gas Operator | Nov 1997 |
| 36 | Uinta Wax Operating, LLC | Fort Worth, TX 76107 | Oil & Gas Operator | Mar 2025 |
| 37 | Uinta-Taylor Fund, LTD | Roosevelt, UT 84066 | Oil & Gas Operator | Nov 2018 |
| 38 | Uintah Investors LLC | Vernal, UT 84078 | Oil & Gas Operator | Mar 2025 |
| 39 | Ulatex Oil & Gas Inc. | Nocona, TX 76255 | Oil & Gas Operator | Dec 1998 |
| 40 | Ullum Oil And Gas Development Corporation, Inc. | Grantsville, WV 26147-0000 | Oil & Gas Operator | Dec 2021 |
| 41 | Ulrich, William J., Jr. & Connie K. | Elma, NY 14059 | Gas Operator | Dec 2023 |
| 42 | Ultra Oil & Gas, Inc. | Centerton, AR 72719 | Oil & Gas Operator | May 2025 |
| 43 | Ultra Petroleum (U.S.A.), Inc. | Granbury, TX 76048 | Oil & Gas Operator | Sep 2003 |
| 44 | Ultra Production Company, LLC | Cedar Bluff, VA 24609 | Gas Operator | Oct 2014 |
| 45 | Ultra Resources Inc | Houston, TX 77060 | Oil & Gas Operator | Sep 2018 |
| 46 | Ultramar Oil & Gas LTD | Houston, TX 77060 | Oil & Gas Operator | Jul 1995 |
| 47 | Ultramar Production Company | | Oil & Gas Operator | Dec 1991 |
| 48 | Ulysses, City Of | Ulysses, KS 67880 | Gas Operator | Jan 2025 |
| 49 | Umberham Oil Company Inc | Oklahoma City, OK 73151-4000 | Oil & Gas Operator | Mar 2025 |
| 50 | Umc Petroleum Corporation | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 51 | Umma Resources, LLC | Portland, TX 78374 | Gas Operator | May 2025 |
| 52 | Ummel'S Tank Ser | | Oil Operator | Sep 1994 |
| 53 | Unbridled Resources, LLC | Houston, TX 77002 | Oil & Gas Operator | May 2025 |
| 54 | Unc Texas Incorp | | Gas Operator | May 1987 |
| 55 | Underground Energy Inc. | | Oil & Gas Operator | Feb 2025 |
| 56 | Underwood Oil & Gas | Casper, WY 82602 | Oil & Gas Operator | Apr 2025 |
| 57 | Underwood Oil And Gas LLC | Chandler, OK 74834-1414 | Oil & Gas Operator | Mar 2025 |
| 58 | Underwood, Donald D. Dba Mustang Oil Co | Salem, WV 26426 | Oil & Gas Operator | Dec 2020 |
| 59 | Underwood, Jim | Graham, TX 76450 | Oil & Gas Operator | Mar 2018 |
| 60 | Underwood, Rip C | Amarillo, TX 79101 | Gas Operator | Sep 1963 |
| 61 | Unger Well Drilling Corp | Dennison, OH 44621 | Oil & Gas Operator | Dec 1999 |
| 62 | Uni Production Company, Inc. | | Oil & Gas Operator | Apr 1988 |
| 63 | Unicon Producing Company | Houston, TX 75252 | Gas Operator | Mar 1994 |
| 64 | Unicorn Drilling Inc | Cody, WY 82414 | Oil Operator | Dec 1998 |
| 65 | Unicorn Energy, Inc. | Elgin, TX 78621 | Oil & Gas Operator | May 2025 |
| 66 | Unicorn Oil & Gas Co Inc | Dorset, OH 44032 | Oil & Gas Operator | Dec 1993 |
| 67 | Unifid Oil & Gas Corp. | | Oil & Gas Operator | Mar 1994 |
| 68 | Unified Oil & Gas Corp. | Snyder, TX 79550 | Oil Operator | May 2025 |
| 69 | Unioil | Denver, CO 80203 | Oil & Gas Operator | Jun 2012 |
| 70 | Union Camp Corp | Dover, OH 44622 | Oil & Gas Operator | Dec 2002 |
| 71 | Union City Boro Muni Auth Erie Cnty | Union City, PA 16438-1326 | Gas Operator | Dec 2023 |
| 72 | Union Crude Company | Baytown, TX 77521 | Oil & Gas Operator | Apr 2018 |
| 73 | Union Crude Operating Co. | Baytown, TX 77521 | Oil Operator | Aug 2003 |
| 74 | Union Development Company Inc | | Oil & Gas Operator | Dec 1992 |
| 75 | Union Diversified, Inc. | | Gas Operator | Dec 2008 |
| 76 | Union Drilling &Management Inc | | Gas Operator | Feb 1991 |
| 77 | Union Exploration Partners, LTD. | | Oil & Gas Operator | Aug 1990 |
| 78 | Union Gas Corp. (Union Gas Co.) | Charleston, WV 25338-0000 | Oil & Gas Operator | Aug 2021 |
| 79 | Union Gas Operating Company | Houston, TX 77014 | Oil & Gas Operator | May 2025 |
| 80 | Union Oil Co | Danville, OH 43014 | Oil & Gas Operator | Dec 2014 |
| 81 | Union Oil Co Of California | Midland, TX 79706 | Oil & Gas Operator | Jan 2022 |
| 82 | Union Operating Corp | Lakewoord, CO 80215 | Oil Operator | Dec 2023 |
| 83 | Union Pacific Austin Chalk Co. | Fort Worth, TX 76101 | Oil & Gas Operator | Jan 2001 |
| 84 | Union Pacific Re | | Oil & Gas Operator | Dec 1996 |
| 85 | Union Pacific Resour | | Oil & Gas Operator | Apr 2002 |
| 86 | Union Pacific Resources Co. | Fort Worth, TX 76101 | Oil & Gas Operator | Sep 2002 |
| 87 | Union Petro Inc | Uniontown, KY 42461 | Oil Operator | Dec 2023 |
| 88 | Union Petrochemical | | Oil & Gas Operator | Dec 1982 |
| 89 | Union Producing Co. | | Gas Operator | Dec 1992 |
| 90 | Union Royalty, Inc. | Midland, TX 79706 | Oil & Gas Operator | Jul 2014 |
| 91 | Union Seaboard Corporation | Houston, TX 77024 | Oil & Gas Operator | Mar 2008 |
| 92 | Union Springs Central School District | Union Springs, NY 13160 | Gas Operator | Dec 2023 |
| 93 | Union Texas Petroleum | Houston, TX 77252 | Oil & Gas Operator | Oct 1991 |
| 94 | Union Texas Petroleum Corp. | Houston, TX 77252-2120 | Oil & Gas Operator | Dec 2014 |
| 95 | Union Valley Petroleum Corporation | Enid, OK 73701 | Oil & Gas Operator | Mar 2025 |
| 96 | Unionville Explo | | Oil Operator | Jul 1984 |
| 97 | Unit Drilling & Exploration Co | Tulsa, OK 74132-5300 | Oil & Gas Operator | Feb 2025 |
| 98 | Unit Manager, Citronelle Unit | | Oil & Gas Operator | Sep 2001 |
| 99 | Unit Petroleum Company | Tulsa, OK 74170 | Oil & Gas Operator | May 2025 |
| 100 | United Company | Lubbock, TX 79408 | Oil & Gas Operator | Jun 1995 |