| 601 | Western Alliance Petroleum | | Oil & Gas Operator | Dec 1987 |
| 602 | Western Natural Gas | | Oil & Gas Operator | Aug 1974 |
| 603 | Western Resources And Clean Energy, LLC | Manti, UT 84642 | Oil & Gas Operator | Mar 2024 |
| 604 | Westport Oil & Gas Company LP | The Woodlands, TX 77380 | Oil & Gas Operator | Feb 2007 |
| 605 | Weststar Exploration Co | Houston, TX 77027 | Oil & Gas Operator | Mar 2021 |
| 606 | Wexpro Company | Rock Springs, WY 82902-0458 | Oil & Gas Operator | Jun 2024 |
| 607 | Whiting Oil And Gas Corporation | Houston, TX 77002 | Oil & Gas Operator | Sep 2024 |
| 608 | Whitley, William W | Denver, CO 80209 | Oil & Gas Operator | Dec 1983 |
| 609 | Whitmar Exploration Company | Denver, CO 80202 | Oil & Gas Operator | May 2024 |
| 610 | Wildrose Resources Corp | Englewood, CO 80110-6007 | Oil & Gas Operator | Mar 2004 |
| 611 | Willard Pease Drilling Co | Grand Junction, CO 81501 | Oil & Gas Operator | Dec 1983 |
| 612 | William G Bush | Grand Junction, CO 81506 | Oil & Gas Operator | Jun 2012 |
| 613 | Williams Production RMT Company | Denver, CO 80202 | Oil & Gas Operator | Oct 2010 |
| 614 | Willstar Energy GP, LLC | Houston, TX 77279 | Oil & Gas Operator | Sep 2013 |
| 615 | Wilshire Oil Co. Of Texas | Oklahoma City, OK 73102 | Oil & Gas Operator | Mar 2004 |
| 616 | Wind River Resources Corp | Park City, UT 84098 | Oil & Gas Operator | Jan 2020 |
| 617 | Winds Exploration And Production, LLC | Houston, TX 77032 | Gas Operator | Jan 2024 |
| 618 | Wintershall Oil & Gas Corp | Houston, TX 77027 | Oil & Gas Operator | Jul 1989 |
| 619 | Wold Oil Properties Inc | Denver, CO 80203 | Oil & Gas Operator | Feb 2018 |
| 620 | Wolverine Gas & Oil Company Of Utah, LLC | Grand Rapids, MI 49503-2616 | Oil & Gas Operator | Jun 2024 |
| 621 | Woosley, James P | Moab, UT 84532 | Oil & Gas Operator | Jun 2024 |
| 622 | Wrights Drilling | Cortez, CO 81321 | Oil & Gas Operator | Oct 1983 |
| 623 | XCL Assetco, LLC | Houston, TX 77007 | Oil & Gas Operator | Jun 2024 |
| 624 | XTO Energy Inc. | Tyler, TX 75703 | Oil & Gas Operator | Sep 2024 |
| 625 | Zinke & Trumbo LTD | Tulsa, OK 74105 | Oil & Gas Operator | Sep 2017 |
| 626 | Zoller & Danneberg Inc | Denver, CO 80203 | Oil & Gas Operator | May 1975 |