| 1301 | Tyrex Oil Company | Casper, WY 82602 | Oil & Gas Operator | May 1997 |
| 1302 | U V Industries | | Oil & Gas Operator | Jan 1993 |
| 1303 | Ultramar Oil & Gas LTD | Houston, TX 77060 | Oil & Gas Operator | Jul 1995 |
| 1304 | Underwood Oil & Gas | Casper, WY 82602 | Oil & Gas Operator | Jul 2026 |
| 1305 | Unicorn Drilling Inc | Cody, WY 82414 | Oil Operator | Dec 1998 |
| 1306 | Unioil | Denver, CO 80203 | Oil & Gas Operator | Dec 2010 |
| 1307 | Union Oil Co Of California | Midland, TX 79706 | Oil & Gas Operator | Jan 2022 |
| 1308 | Union Texas Petroleum | Houston, TX 77252 | Oil & Gas Operator | Oct 1991 |
| 1309 | Unit Drilling & Exploration Co | Tulsa, OK 74132-5300 | Oil & Gas Operator | May 2026 |
| 1310 | Unit Petroleum Company | Tulsa, OK 74170 | Oil & Gas Operator | Sep 2026 |
| 1311 | United Energy Corporation | San Antonio, TX 78209 | Oil & Gas Operator | Sep 2026 |
| 1312 | United Natural Gas LLC | Denver, CO 80202 | Oil & Gas Operator | Feb 2020 |
| 1313 | United Natural Resources Corp | | Oil Operator | Jan 1986 |
| 1314 | United Petroleum Corporation | Edgwater, CO 80214 | Oil & Gas Operator | May 1996 |
| 1315 | United Utilities Corporation | Conroe, TX 77301 | Oil & Gas Operator | Oct 1998 |
| 1316 | Universal Fuels Company | | Oil & Gas Operator | Oct 1993 |
| 1317 | Updike Resources Inc | Newcastle, WY 82701 | Oil & Gas Operator | Jun 1998 |
| 1318 | Urban Oil & Gas Group, LLC | Plano, TX 75074 | Oil & Gas Operator | Sep 2026 |
| 1319 | Urroz Oil & Gas LLC | Evanston, WY 82931 | Oil & Gas Operator | Jun 2020 |
| 1320 | Us Energy Corp. | Houston, TX 77057 | Oil & Gas Operator | Dec 2021 |
| 1321 | Us Ore Corporation | Pacific Beach, CA 92109 | Oil Operator | Feb 2014 |
| 1322 | USA Energy LLC | Lance Creek, WY 82222 | Oil & Gas Operator | Nov 2024 |
| 1323 | USA Exploration & Production LLC | Mills, WY 82644 | Oil & Gas Operator | Sep 2012 |
| 1324 | V A Resources LLC | Casper, WY 82601 | Oil Operator | Apr 2016 |
| 1325 | Valero Producing Company | | Oil Operator | Sep 1987 |
| 1326 | Valkyrie Operating LLC | Denver, CO 80202 | Oil & Gas Operator | Jul 2026 |
| 1327 | Van Norman Pipe And Supply | | Oil & Gas Operator | Mar 2010 |
| 1328 | Vanmark Jack | Torrington, WY 82240 | Oil Operator | Dec 1997 |
| 1329 | Vaquero Big Horn LLC | Bakersfield, CA 93309 | Oil & Gas Operator | Nov 2025 |
| 1330 | Vaquero Energy Inc | Bakersfield, CA 93309 | Oil & Gas Operator | May 2023 |
| 1331 | Vast Oil Inc | Fullerton, CA 92832 | Oil & Gas Operator | Mar 2024 |
| 1332 | Vastar Resources Inc | Houston, TX 77253 | Oil & Gas Operator | Apr 2026 |
| 1333 | VCP Wyoming LLC | | Oil Operator | Jul 2026 |
| 1334 | Vecta Oil & Gas LTD | Dallas, TX 75235 | Oil & Gas Operator | Jun 2026 |
| 1335 | Vector Minerals Corporation | Aurora, CO 80015 | Oil & Gas Operator | Jun 2026 |
| 1336 | Vermilion Energy USA LLC | | Oil & Gas Operator | Jul 2025 |
| 1337 | Vessels Oil & Gas Company | Denver, CO 80265 | Oil & Gas Operator | Dec 1998 |
| 1338 | Viable Resources Inc | Casper, WY 82601 | Oil & Gas Operator | Sep 1989 |
| 1339 | Vicorp Energy Inc | Denver, CO 80202-4927 | Oil & Gas Operator | Mar 2001 |
| 1340 | Viking Resources Corp | Deerfield, OH 44411-0160 | Oil & Gas Operator | Dec 2007 |
| 1341 | Vintage Petroleum, Inc. | Houston, TX 77046 | Oil & Gas Operator | Apr 2026 |
| 1342 | Viola Production Inc | Dallas, TX 75251 | Oil & Gas Operator | Sep 2026 |
| 1343 | Vortex Petroleum Inc | Centennial, CO 80111 | Oil Operator | Jan 2026 |
| 1344 | Voyager Exploration Inc | Denver, CO 80202 | Oil & Gas Operator | May 2006 |
| 1345 | Wacker Oil Inc. | Houston, TX 77002 | Oil & Gas Operator | Aug 1996 |
| 1346 | Waggoner-Baldridge Energy | | Oil Operator | Jun 1988 |
| 1347 | Wagner & Brown Limited Partnership | Midland, TX 79701 | Oil & Gas Operator | Feb 2013 |
| 1348 | Wainoco Oil & Gas Company | Houston, TX 77024 | Oil & Gas Operator | Dec 2005 |
| 1349 | Walker L Willis | | Oil Operator | Dec 1985 |
| 1350 | Wallway M J | Casper, WY 82601 | Oil & Gas Operator | Jan 1993 |
| 1351 | Wapiti Oil & Gas LLC | Houston, TX 77024 | Oil Operator | Dec 2011 |
| 1352 | Wapiti Operating, LLC | Houston, TX 77043 | Oil & Gas Operator | Sep 2026 |
| 1353 | Ward Petroleum Corporation | Enid, OK 73702 | Oil & Gas Operator | May 2026 |
| 1354 | Ware House Industries | Casper, WY 82605 | Oil & Gas Operator | Dec 2013 |
| 1355 | Warrego Oil & Gas LLC | Lander, WY 82520 | Oil Operator | May 2018 |
| 1356 | Warren E & P Inc | Dallas, TX 75240 | Oil & Gas Operator | Jul 2026 |
| 1357 | Warren Enterprises Inc | Gillette, WY 82718 | Oil Operator | Dec 2022 |
| 1358 | Washakie Energies Company | Worland, WY 82401 | Oil & Gas Operator | Dec 2019 |
| 1359 | Washakie Oil Company | | Oil & Gas Operator | Dec 1989 |
| 1360 | Washburn Lee | Newcastle, WY 82701 | Oil Operator | Jan 2025 |
| 1361 | Washington Energy Exploration | | Oil & Gas Operator | Dec 1997 |
| 1362 | Waterford Production Co | | Oil Operator | Oct 1992 |
| 1363 | Wave Petroleum Operating LLC | Denver, CO 80202 | Oil & Gas Operator | Jul 2026 |
| 1364 | Weaver Dale Inc | Powell, WY 82435 | Oil Operator | Apr 2005 |
| 1365 | Weaver Oil Inc | | Oil & Gas Operator | Oct 2011 |
| 1366 | Webb Resources Inc | | Oil & Gas Operator | Dec 1985 |
| 1367 | Webster Joe | | Oil Operator | Apr 1987 |
| 1368 | Wellstar Corporation | Northglenn, CO 80233 | Oil & Gas Operator | Jul 2026 |
| 1369 | Wem Joint Venture | Gillette, WY 82716 | Oil & Gas Operator | Sep 2015 |
| 1370 | Wesco Operating Inc | Casper, WY 82602 | Oil & Gas Operator | Jul 2026 |
| 1371 | Wesco Production LLC | | Oil & Gas Operator | Jun 2025 |
| 1372 | Wessely Energy Corporation | | Oil & Gas Operator | Feb 1989 |
| 1373 | West Gas Inc | | Oil & Gas Operator | Dec 2017 |
| 1374 | Westburne Petroleum Inc | | Oil Operator | Jun 1990 |
| 1375 | Westech Energy Corporation | Denver, CO 80237 | Oil & Gas Operator | Mar 2011 |
| 1376 | Western American Resources LLC | Denver, CO 80202 | Oil & Gas Operator | Jun 2024 |
| 1377 | Western Gas Resources Inc | Denver, CO 80202 | Oil & Gas Operator | Sep 2004 |
| 1378 | Western Interior Energy Inc. | Denver, CO 80202 | Oil & Gas Operator | Dec 2016 |
| 1379 | Western Interior Oil & Gas Corp | Casper, WY 82602 | Oil & Gas Operator | May 2015 |
| 1380 | Western Oil Refining Company | Kemmerrer, WY 83101 | Oil & Gas Operator | Dec 1994 |
| 1381 | Western Operating Company | Denver, CO 80204 | Oil & Gas Operator | Apr 2026 |
| 1382 | Westport Oil & Gas Company LP | The Woodlands, TX 77380 | Oil & Gas Operator | Feb 2007 |
| 1383 | Weststar Oil & Gas Inc | Edmond, OK 73013 | Oil & Gas Operator | Jun 2026 |
| 1384 | Wexpro Company | Rock Springs, WY 82902-0458 | Oil & Gas Operator | Jun 2026 |
| 1385 | Wexpro Development Company | Salt Lake City, UT 84111 | Oil & Gas Operator | May 2026 |
| 1386 | Wexpro II Company | Salt Lake City, UT 84111 | Oil & Gas Operator | Jun 2026 |
| 1387 | Wheless Drilling Company | | Oil & Gas Operator | Dec 1989 |
| 1388 | Whisler Enterprise Company | Erie, CO 80516 | Oil & Gas Operator | Jul 2026 |
| 1389 | White Rock Oil & Gas, LLC | Plano, TX 75024 | Oil & Gas Operator | Sep 2026 |
| 1390 | Whiting Oil And Gas Corporation | Houston, TX 77002 | Oil & Gas Operator | Sep 2026 |
| 1391 | Wichita River Oil Corporation | Englewood, CO 80111 | Oil & Gas Operator | Apr 2009 |
| 1392 | Wilbanks Exploration Inc | Denver, CO 80202 | Oil & Gas Operator | May 2002 |
| 1393 | Wildfire Partners Inc | Ardmore, OK 73402 | Oil & Gas Operator | Dec 2009 |
| 1394 | Williams Exploration Company | | Oil & Gas Operator | Dec 1986 |
| 1395 | Williams Ted H | | Oil & Gas Operator | Dec 2008 |
| 1396 | Williston Basin Cosul-Profit SH | | Oil Operator | Dec 1989 |
| 1397 | Wilshire Enterprises Inc | Oklahoma City, OK 73102 | Oil & Gas Operator | Mar 2015 |
| 1398 | Win Oil Company | Russell, KS 67665 | Oil & Gas Operator | Jul 2021 |
| 1399 | Winco Petroleum Corp | Denver, CO 80202 | Oil & Gas Operator | Dec 1997 |
| 1400 | Wind River Energy Commission | | Oil Operator | Mar 2026 |