| U S Smelting | 102257 | — | 1 | 1 |
| UGC Midstream Ltd, LLCActive | 104890 | Rangely | 0 | 0 |
| Uinta Oil & Gas | 102260 | Roosevelt | 1 | 1 |
| Uinta Oil & Gas | 102261 | Roosevelt | 0 | 0 |
| Uinta Oil Refining Co | 102262 | — | 1 | 1 |
| Uinta Wax Operating, LLCActive | 105205 | Fort Worth | 1,313 | 2 |
| Uinta-Taylor Fund, LTD | 102263 | Roosevelt | 0 | 0 |
| Uintah Development Company | 102264 | — | 3 | 1 |
| Uintah Dome Oil & Gas Corp | 102265 | N Hollywood | 1 | 1 |
| Uintah Gas Co | 102266 | — | 1 | 1 |
| Uintah Investors LLCActive | 102267 | Vernal | 10 | 1 |
| Uintah Management Corp | 102268 | Salt Lake City | 4 | 1 |
| Uintah Oil & Exploration | 102269 | Denver | 2 | 1 |
| Ultra Resources Inc | 102270 | Englewood | 102 | 1 |
| Ultramar Oil & Gas LTD | 102271 | Houston | 0 | 0 |
| Umc Petroleum Corporation | 102273 | Newcastle | 0 | 0 |
| Underwood, Rip C | 102274 | Amarillo | 5 | 2 |
| Unicon Producing Company | 102276 | Houston | 3 | 1 |
| Union Oil Co of California | 102278 | Casper | 70 | 9 |
| Union Pacific Fuels Inc | 102279 | Ft Worth | 0 | 0 |
| Union Pacific Resources Co | 102280 | Houston | 4 | 2 |
| Union Petrochemical | 102281 | — | 2 | 1 |
| Union Texas Explor Corp | 102282 | — | 0 | 0 |
| Union Texas Petroleum | 102283 | Houston | 8 | 3 |
| United Crude Company | 102284 | Tulsa | 0 | 0 |
| United Energy Corp | 102285 | — | 6 | 1 |
| United Oil & Min Limited P | 102286 | Austin | 2 | 1 |
| United Producing Co Inc | 102288 | — | 1 | 1 |
| United Technical Inc | 102291 | — | 12 | 1 |
| United Utilities Corp | 102292 | Conroe | 3 | 1 |
| Universal Energy | 102293 | Tulsa | 1 | 1 |
| Universal Resources Corp | 102294 | Denver | 1 | 1 |
| unknown | 102295 | Salt Lake City | 68 | 4 |
| Unknown Producers | 102296 | — | 0 | 0 |
| Uqueahgut Inc | 102297 | — | 0 | 0 |
| Urado Development Co | 102298 | — | 5 | 1 |
| Urban Oil & Gas Group, LLCActive | 104712 | Plano | 959 | 2 |
| Urban Oiol | 105400 | — | 0 | 0 |
| Urban, C A & Tersell L W | 102299 | — | 1 | 1 |
| US Oil & Gas IncActive | 102300 | Cortez | 80 | 1 |
| Usona Oil Company | 102301 | — | 3 | 1 |
| Ut Div Wildlife Resources | 102302 | Price | 0 | 0 |
| Utacal Oil Co | 102304 | — | 27 | 1 |
| Utah Drilling Co | 102308 | — | 1 | 1 |
| Utah Duchess Oil Co | 102309 | — | 1 | 1 |
| Utah Energy Acquisitions, LLCActive | 105520 | Allen | 8 | 1 |
| Utah Gas & Oil Corp | 102310 | — | 1 | 1 |
| Utah Gas Op LtdActive | 104383 | Rangely | 666 | 2 |
| Utah Gas Operating Solutions, LLCActive | 102311 | Minneapolis | 22 | 2 |
| Utah Geological Survey | 102312 | — | 14 | 1 |
| Utah Great Eagle LLC | 102313 | Anchorage | 1 | 1 |
| Utah Oil Company | 102314 | — | 1 | 1 |
| Utah Oil Development Co | 102315 | — | 2 | 2 |
| Utah Oil Refining Co | 102316 | — | 13 | 4 |
| Utah Parks Petroleum Co | 102317 | — | 13 | 1 |
| Utah Penn Oil Co | 102318 | Austin | 3 | 2 |
| Utah Petrochemical | 102319 | Ogden | 12 | 1 |
| Utah Petroleum Corporation | 102320 | — | 2 | 1 |
| Utah Plateau Uranium Co | 102321 | — | 2 | 1 |
| Utah Potash, LLCActive | 105832 | West Jordan | 0 | 0 |
| Utah Southern Oil Company | 102322 | — | 26 | 6 |
| Utah Southern Phillips | 102323 | — | 0 | 0 |
| Utah Vernal Oil Co | 102324 | — | 1 | 1 |
| Utah-Westar Drl Ventures | 102325 | Dallas | 2 | 1 |
| Ute Energy LLC | 102326 | Ft Duchesne | 0 | 0 |
| Ute Energy Upstream Holdings LLC | 102327 | Denver | 5 | 1 |
| Ute Indian Tribe | 102328 | Ft Duchesne | 0 | 0 |
| Ute Indian Tribe | 102329 | Roosevelt | 0 | 0 |
| Ute Oil Company | 102330 | Durango | 0 | 0 |
| Ute Production Company | 102331 | — | 6 | 1 |
| Ute Royalty Corp | 102332 | — | 3 | 2 |
| Utex Oil Company | 102333 | Elko | 26 | 3 |
| Uton Energy Inc | 102334 | West Valley | 0 | 0 |
| VA Resources LLC | 102335 | Casper | 1 | 1 |
| Valence Resources, LLCActive | 105229 | Durango | 6 | 1 |
| Valkor Oil & Gas, LLC | 105331 | Park City | 0 | 0 |
| Valley Operating Inc | 102336 | Denver | 5 | 1 |
| Valwood Production Co | 102337 | — | 1 | 1 |
| Van Ryan, L O | 102338 | Evergreen | 0 | 0 |
| Vanco Oil Company | 102339 | — | 4 | 1 |
| Vanover, Dan | 102340 | Grand Junction | 4 | 1 |
| Vantage Energy Uinta LLC | 102341 | Denver | 28 | 2 |
| Vaquero Uinta, LLCActive | 105145 | Fort Worth | 220 | 1 |
| Vaughey, Vaughey & Blackburn | 102342 | — | 1 | 1 |
| Verdad Resources Operating LLCActive | 105863 | Dallas | 0 | 0 |
| Vernal Intermtn Petroleum | 102344 | Sandy | 3 | 1 |
| Vernal Oil & Gas Co | 102345 | — | 2 | 1 |
| Vertical Limits Inc | 102346 | Cortez | 0 | 0 |
| Viking Oil Company | 102347 | — | 5 | 1 |
| Vintage Petroleum Inc | 102348 | Tulsa | 0 | 0 |
| Virgin Petroleum Corp | 102349 | — | 2 | 1 |
| Virgin River Constructors | 105797 | Cedar City | 0 | 0 |
| Virtus Oil & Gas Corp | 102350 | Las Vegas | 1 | 1 |
| Virtus Operations Inc | 102351 | Houston | 0 | 0 |
| Vortt Exploration Co Inc | 102352 | Ft Worth | 3 | 2 |
| Vukasovich Drilling | 102353 | — | 30 | 1 |
| W C Investments LTD | 102354 | Salt Lake City | 2 | 1 |
| W H Investment Co | 102355 | — | 1 | 1 |
| Waggoner & Zeller Oil Co | 102357 | — | 1 | 1 |
| Wainoco Oil & Gas Co | 102358 | Houston | 2 | 2 |
| Walden Energy Ventures LLC | 102359 | Tulsa | 0 | 0 |
| Walker Energy Group | 102360 | Houston | 1 | 1 |
| Walker Explor & Prod Corp | 102361 | Unknown | 2 | 1 |
| Walker Production Co | 102362 | — | 1 | 1 |
| Walker, J F | 102363 | — | 1 | 1 |
| Walklin Petroleum Co | 102364 | — | 7 | 1 |
| Walter Nelson Et Al | 102365 | — | 2 | 1 |
| Walther, John | 102366 | — | 1 | 1 |
| Walton, Paul T | 102367 | — | 3 | 2 |
| Walton, WM H | 102368 | Dallas | 0 | 0 |
| Walton-Kearns | 102369 | — | 1 | 1 |
| Wapiti Operating, LLCActive | 102370 | Houston | 578 | 3 |
| Ward, R A | 102371 | — | 1 | 1 |
| Warner Valley Oil | 102372 | — | 7 | 2 |
| Warren American Oil Co | 102373 | Tulsa | 6 | 1 |
| Wasatch Gas Devel Inc | 102374 | Dallas | 4 | 1 |
| Wasatch Oil & Gas Corp | 102375 | Farmington | 2 | 1 |
| Wasatch Oil & Gas LLC | 102376 | N Salt Lake City | 0 | 0 |
| Wasatch Res & Minerals Inc | 102377 | Manti | 1 | 1 |
| Wasatch Water Logistics, LLC | 105183 | Houston | 0 | 0 |
| Wasden, Glen M | 102378 | — | 1 | 1 |
| Washington Energy Expl Inc | 102379 | Englewood | 0 | 0 |
| Water Disposal IncActive | 102381 | Layton | 3 | 1 |
| Water Recovery, LLC | 104636 | Roosevelt | 0 | 0 |
| Webb Resources Inc | 102383 | — | 7 | 3 |
| Webb, Max D | 102384 | Farmington | 1 | 1 |
| Wegemann, C H | 102385 | — | 1 | 1 |
| Weger Petroleum Corp | 102386 | Dallas | 1 | 1 |
| Weightman, J W | 102387 | — | 1 | 1 |
| Wellington Drilling | 102388 | Salt Lake City | 1 | 1 |
| Wells Petroleum Corp | 102390 | Salt Lake City | 0 | 0 |
| Wells, Donnell O | 102391 | — | 1 | 1 |
| Wem Castlegate LLC | 102392 | Orem | 0 | 0 |
| WEM Operating, LLCActive | 105398 | Provo | 102 | 1 |
| Wem Petroleum Inc | 102393 | Nirada | 6 | 2 |
| Wesco Operating, IncActive | 102394 | Casper | 71 | 3 |
| Wesgra CorporationActive | 102396 | Mexican Hat | 191 | 1 |
| Wessely Energy Co | 102397 | Dallas | 2 | 1 |
| West Hazmat Oil Field Serv | 102398 | Vernal | 1 | 1 |
| West Hazmat Oil Field Serv | 102399 | Englewood | 0 | 0 |
| West Henry Mountain Corp | 102400 | — | 1 | 1 |
| West Toledo Mines Co | 102401 | — | 1 | 1 |
| West, Robert S | 102402 | — | 10 | 2 |
| Westates Petroleum Co | 102403 | Denver | 1 | 1 |
| Westburne Expl Inc | 102404 | Denver | 0 | 0 |
| Westcoast Oil & Gas | 102406 | Calgary, Alberta | 1 | 1 |
| Westech Energy Corp | 102407 | Denver | 0 | 0 |
| Western Alliance Petroleum | 102408 | — | 9 | 2 |
| Western Allies | 102409 | — | 2 | 1 |
| Western Crude Oil Co | 102412 | — | 2 | 1 |
| Western Discovery USA Inc | 102413 | San Luis Obispo | 0 | 0 |
| Western Energy Operating LLC | 102414 | Casper | 0 | 0 |
| Western Gas ResourcesActive | 102415 | Denver | 0 | 0 |
| Western Gas ResourcesActive | 102416 | Denver | 0 | 0 |
| Western Golden Gas Company | 102417 | Salt Lake City | 1 | 1 |
| Western Hydro Carbon Corp | 102418 | — | 1 | 1 |
| Western Investment Co | 102419 | — | 1 | 1 |
| Western Natural Gas | 102421 | — | 4 | 1 |
| Western Oil & Mineral Inc | 102422 | Salt Lake City | 1 | 1 |
| Western Petroleum Drl Co | 102423 | — | 1 | 1 |
| Western Resources and Clean Energy, LLCActive | 105213 | Manti | 2 | 1 |
| Western States Development | 102424 | — | 2 | 2 |
| Western States Refining | 102425 | — | 1 | 1 |
| Western United Mines Inc | 102427 | Salt Lake City | 1 | 1 |
| Western Venture Corp | 102428 | Ogden | 3 | 1 |
| Western Waste Inc | 102429 | Salt Lake City | 0 | 0 |
| Western Water Solutions LLC | 102430 | Provo | 0 | 0 |
| Western X Oil Company | 102431 | — | 0 | 0 |
| Westmont Engineering | 102432 | Reseda | 0 | 0 |
| Westport Oil & Gas Co Inc | 102433 | Denver | 0 | 0 |
| Westport Oil & Gas Co LP | 102434 | Denver | 110 | 2 |
| Weststar Exploration CoActive | 102436 | Houston | 105 | 1 |
| Westwater Farms LLC | 102437 | Grand Junction | 0 | 0 |
| Westwood Oil Co | 102438 | — | 3 | 1 |
| Wexpro CompanyActive | 102439 | Rock Springs | 176 | 7 |
| Wheeler Machinery Co | 102440 | Salt Lake City | 0 | 0 |
| Whisnant, W P | 102441 | — | 2 | 2 |
| White Canyon Mining Co | 102442 | Grand Junction | 5 | 1 |
| White Throne Oil Co | 102443 | — | 2 | 1 |
| White, E R | 102444 | — | 3 | 1 |
| Whiting Oil & Gas Corporation | 102445 | Denver | 0 | 0 |
| Whiting Oil & Gas Corporation | 102446 | Denver | 0 | 0 |
| Whitley, William W | 102447 | Denver | 8 | 1 |
| Whitlock, L E | 102448 | Denver | 2 | 2 |
| Whitmar Exploration Company | 102449 | Denver | 16 | 1 |
| Whitney, Frank M | 102450 | — | 1 | 1 |
| Whyte, Charles | 102451 | — | 3 | 1 |
| Whyte-Moore | 102452 | — | 1 | 1 |
| Wilcox, Clinton III | 102453 | Grass Valley | 0 | 0 |
| Wildcat Landfarm, LLC | 105202 | Fort Worth | 0 | 0 |
| Wildhorse Petroleum Inc | 102454 | Vernal | 0 | 0 |
| Wildrose Resources Corp | 102455 | Englewood | 12 | 2 |
| Willard Pease Drilling Co | 102456 | Grand Junction | 4 | 2 |
| William G Bush | 102457 | Grand Junction | 35 | 2 |
| Williams Exploration Co | 102458 | Houston | 1 | 1 |
| Williams Prod Co LLC | 102459 | Tulsa | 0 | 0 |
| Williams Prod Rky Mtn Co | 102460 | Denver | 0 | 0 |
| Williams Prod Rmt Co | 102461 | Denver | 5 | 1 |
| Williams Prod Rmt Co LLC | 102462 | Denver | 0 | 0 |
| Williams Production Co | 102463 | Tulsa | 0 | 0 |