| 501 | Ultramar Oil & Gas LTD | Houston, TX 77060 | Oil & Gas Operator | Jul 1995 |
| 502 | Umc Petroleum Corporation | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 503 | Union Oil Co Of California | Midland, TX 79706 | Oil & Gas Operator | Jan 2022 |
| 504 | Union Texas Petroleum Corp. | Houston, TX 77252-2120 | Oil & Gas Operator | Dec 2014 |
| 505 | Unit Petroleum Company | Tulsa, OK 74170 | Oil & Gas Operator | Apr 2024 |
| 506 | United Oil Corporation | Denver, CO 80202-3813 | Oil & Gas Operator | Jan 2024 |
| 507 | United Production Company LLC | Edmond, OK 73083-5348 | Oil & Gas Operator | Feb 2024 |
| 508 | Vaughan Otto M | | Oil & Gas Operator | Apr 2014 |
| 509 | Veenker Resources, Inc. | Oklahoma City, OK 73113 | Oil & Gas Operator | Feb 2024 |
| 510 | Vega Energy Company | Oklahoma City, OK 73116 | Oil & Gas Operator | Sep 2015 |
| 511 | Viersen & Cochran Drilling Company | | Oil & Gas Operator | May 2015 |
| 512 | Vitol Inc | Houston, TX 77098 | Oil & Gas Operator | Sep 2023 |
| 513 | W S Crude Oil Purchasing Inc | Oklahoma City, OK 73129-7613 | Oil & Gas Operator | May 2008 |
| 514 | Ward Petroleum Corporation | Enid, OK 73702 | Oil & Gas Operator | Jan 2024 |
| 515 | Wentworth Operating Company | Oklahoma City, OK 73162-1863 | Oil & Gas Operator | Mar 2024 |
| 516 | Western Oil And Gas Development Corp | Oklahoma City, OK 73103-3735 | Oil & Gas Operator | Feb 2024 |
| 517 | Western Oil Company | Midland, TX 79702 | Oil & Gas Operator | Jul 2014 |
| 518 | Westland Oil Development Corp. | Conroe, TX 77305 | Oil & Gas Operator | Mar 2008 |
| 519 | Wil-MC Oil Corporation The | Irving, TX 75015-2510 | Oil & Gas Operator | Mar 1999 |
| 520 | Wilcox Pipe & Supply Co | Oklahoma City, OK 73189 | Oil & Gas Operator | May 2006 |
| 521 | Wildhorse Operating Company | Ardmore, OK 73402 | Oil & Gas Operator | Apr 2024 |
| 522 | Williams Dale And Dorothy Family Trust | | Oil & Gas Operator | Jan 2024 |
| 523 | Wilshire Enterprises Inc | Oklahoma City, OK 73102 | Oil & Gas Operator | Mar 2015 |
| 524 | Windward Development LLC | Tulsa, OK 74136-7007 | Oil & Gas Operator | Jul 2019 |
| 525 | WLW Oil & Gas LLC | Kingfisher, OK 73750-1102 | Oil & Gas Operator | Feb 2024 |
| 526 | Woodward Iodine Corporation | Woodward, OK 73802-1245 | Oil & Gas Operator | Feb 2024 |
| 527 | Xanadu Exploration Company | Broken Arrow, OK 74014 | Oil & Gas Operator | Feb 2024 |
| 528 | XTO Energy Inc. | Spring, TX 77389 | Oil & Gas Operator | Apr 2024 |
| 529 | Y D F Inc | Oklahoma City, OK 73085-0680 | Oil & Gas Operator | Mar 2024 |
| 530 | Yale Oil Association, Inc. | Oklahoma City, OK 73105 | Oil & Gas Operator | Apr 2024 |
| 531 | Zenergy Inc | Tulsa, OK 74136 | Oil & Gas Operator | Feb 2024 |
| 532 | Zimet Brothers Inc | | Oil Operator | Mar 2008 |