| 1 | Wagner, Duer & Co. | Fort Worth, TX 76102 | Oil & Gas Operator | Jan 1999 |
| 2 | Wainoco Oil & Gas Company | Houston, TX 77024 | Oil & Gas Operator | Dec 2005 |
| 3 | Waters Eng. & Operating, Inc. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Sep 2013 |
| 4 | WCS Oil & Gas Corporation | Dallas, TX 75209 | Oil & Gas Operator | Aug 2021 |
| 5 | Weber Energy Corporation | Dallas, TX 75219 | Oil & Gas Operator | Feb 2017 |
| 6 | Welder Exploration & Prod., Inc. | San Antonio, TX 78212 | Oil & Gas Operator | Dec 2022 |
| 7 | Welhausen Operating Company, LP | Beeville, TX 78104 | Oil & Gas Operator | Nov 2016 |
| 8 | Wen-Be | Jourdanton, TX 78026 | Oil & Gas Operator | Oct 2025 |
| 9 | Western Field Exploration, Inc. | Dilley, TX 78017 | Oil & Gas Operator | Oct 2025 |
| 10 | White Oak Operating Company LLC | Houston, TX 77077 | Oil & Gas Operator | Oct 2025 |
| 11 | Whiting Oil And Gas Corporation | Houston, TX 77002 | Oil & Gas Operator | Oct 2025 |
| 12 | Whiting Petroleum Corporation | Denver, CO 80290 | Oil & Gas Operator | Jan 2025 |
| 13 | Williams, Clayton Energy, Inc. | Houston, TX 77070 | Oil & Gas Operator | Oct 2025 |
| 14 | Williams, Clayton Energy, L.L.C | Midland, TX 79705 | Oil & Gas Operator | May 1993 |
| 15 | Williams, Clayton W., Jr., Inc. | Midland, TX 79705 | Oil & Gas Operator | Mar 2008 |
| 16 | Windsor Exploration Company | Dallas, TX 75204 | Oil & Gas Operator | Jan 1994 |
| 17 | Wolco Energy, Inc. | Dallas, TX 75220 | Oil & Gas Operator | May 1997 |
| 18 | World Energy Corporation | Laredo, TX 78041 | Oil & Gas Operator | Aug 2003 |
| 19 | Wright Brothers Energy, Inc. | Boerne, TX 78006 | Oil & Gas Operator | Oct 2025 |