| 501 | Weir Oil Co. Inc. | | Oil & Gas Operator | Dec 2007 |
| 502 | Weise, Kevin L. And Kathy L. | Sinclairville, NY 14782 | Gas Operator | Dec 2024 |
| 503 | Weiser-Brown Oil Co | Magnolia, AR 71754 | Oil Operator | Jan 2025 |
| 504 | Weiser-Brown Operating Company | Magnolia, AR 71754 | Oil & Gas Operator | Dec 2025 |
| 505 | Weiss Drilling Inc | Jerusalem, OH 43747 | Oil & Gas Operator | Dec 2024 |
| 506 | Weiss Oil Co. | Streator, IL 61364 | Oil & Gas Operator | Dec 1997 |
| 507 | Weitzman Irvin | | Oil & Gas Operator | Sep 1988 |
| 508 | Wejco, Inc. | Rising Star, TX 76471 | Oil & Gas Operator | Dec 2025 |
| 509 | Welch Energy LLC | Drumright, OK 74030 | Oil Operator | Oct 2025 |
| 510 | Welch Family Trust | Ada, OK 74820-9643 | Oil & Gas Operator | Apr 2015 |
| 511 | Welch Foods Inc A Cooperative | North East, PA 16428-1209 | Gas Operator | Dec 1998 |
| 512 | Welch Oil & Gas Company | Parkersburg, WV 26104 | Oil & Gas Operator | Jun 2013 |
| 513 | Welcome Well Serv. & Boykin Bros | Abilene, TX 79604 | Oil & Gas Operator | Apr 1995 |
| 514 | Weldbank Energy Corp | Warren, PA 16365-5114 | Oil & Gas Operator | Dec 2024 |
| 515 | Welder Exploration & Prod., Inc. | San Antonio, TX 78212 | Oil & Gas Operator | Dec 2022 |
| 516 | Welder Operating, Inc. | San Antonio, TX 78205 | Oil & Gas Operator | Mar 2001 |
| 517 | Welder-Heyer Energy, Inc. | San Antonio, TX 78205 | Oil & Gas Operator | Feb 2001 |
| 518 | Welderxp LTD. | San Antonio, TX 78212 | Oil & Gas Operator | Dec 2025 |
| 519 | Weldon Corporation | Houston, TX 77056 | Oil Operator | Feb 2020 |
| 520 | Welhausen Operating Co., Inc. | Beeville, TX 78104 | Oil & Gas Operator | Aug 2003 |
| 521 | Welhausen Operating Company, LP | Beeville, TX 78104 | Oil & Gas Operator | Nov 2016 |
| 522 | Well Management Services Inc | | Oil & Gas Operator | Dec 2001 |
| 523 | Well Recycling Company | Olney, TX 76374 | Oil Operator | Aug 2005 |
| 524 | Well Renewal Inc | Tulsa, OK 74103-0091 | Oil Operator | Mar 2015 |
| 525 | Well Tech Oil And Gas, Inc. | Wichita, KS 67206 | Oil Operator | Sep 2020 |
| 526 | Well Water Management | | Oil & Gas Operator | Oct 2025 |
| 527 | Well-Co Solutions, LLC | Batson, TX 77519 | Oil Operator | Dec 2025 |
| 528 | Wellco Energy Inc | Harrah, OK 73045 | Oil & Gas Operator | Oct 2025 |
| 529 | Wellco Production LLC | Purcell, OK 73080-6833 | Oil & Gas Operator | Oct 2025 |
| 530 | Wellington Operating Company | | Oil & Gas Operator | Aug 2025 |
| 531 | Wellington Securities, Inc. | Plano, TX 75093 | Gas Operator | Jul 2014 |
| 532 | Wellmaster Production Co LLC | | Oil & Gas Operator | Jul 2015 |
| 533 | Wells Allen W | Barnsdall, OK 74002 | Oil & Gas Operator | Oct 2025 |
| 534 | Wells Edward K | Sapulpa, OK 74066-4243 | Oil & Gas Operator | Jun 2004 |
| 535 | Wells Energy Com | | Oil & Gas Operator | Mar 1994 |
| 536 | Wells Jimme D | Ponca City, OK 74604 | Oil Operator | Oct 2025 |
| 537 | Wells Oil Compan | | Gas Operator | Sep 1984 |
| 538 | Wells Oil, LLC | Gridley, KS 66852 | Oil Operator | Sep 2025 |
| 539 | Wells Oilfield Services, Inc. | Graham, TX 76450 | Oil & Gas Operator | Dec 2025 |
| 540 | Wells, Michael E. | Springville, NY 14141 | Gas Operator | Dec 2024 |
| 541 | Wells-Battelstei | | Oil & Gas Operator | Mar 1993 |
| 542 | Wells-Battelstein O&G, Inc. | | Gas Operator | Dec 1986 |
| 543 | Wellspring Oil LLC | | Oil Operator | Nov 2025 |
| 544 | Wellstar Corporation | Northglenn, CO 80233 | Oil & Gas Operator | Oct 2025 |
| 545 | Wellsville Oil C | | Oil Operator | Dec 1996 |
| 546 | Wellsville Oil Co | Wellsville, KS 66092 | Oil Operator | Sep 2000 |
| 547 | Wellwin Drilling | | Oil & Gas Operator | Dec 1994 |
| 548 | Wellwin Drilling Corporation | Wellington, KS 67152 | Oil & Gas Operator | Sep 2025 |
| 549 | Welsh Hills Oil & Gas Co | Newark, OH 43055 | Oil & Gas Operator | Dec 1999 |
| 550 | Wem Joint Venture | Gillette, WY 82716 | Oil & Gas Operator | Sep 2015 |
| 551 | Wem Operating, LLC | Provo, UT 84604 | Oil & Gas Operator | Nov 2025 |
| 552 | Wema Natural Res, Inc | Sharon Grove, KY 42280 | Oil Operator | Dec 2021 |
| 553 | Wen-Be | Jourdanton, TX 78026 | Oil & Gas Operator | Dec 2025 |
| 554 | Wendy Oil Company | Wichita Falls, TX 76307 | Oil & Gas Operator | Dec 2025 |
| 555 | Wenert Trich | | Oil & Gas Operator | Oct 1988 |
| 556 | Wenert Trich Oil | | Oil & Gas Operator | Jul 1990 |
| 557 | Wenexco, Inc. | Streetman, TX 75859 | Oil & Gas Operator | Dec 2025 |
| 558 | Wengerd, Noah A. | Sherman, NY 14781 | Gas Operator | Dec 2024 |
| 559 | Wenner Petroleum Corp | Englewood, CO 80111 | Oil & Gas Operator | Dec 1986 |
| 560 | Wente Exploration Inc | Oklahoma City, OK 73102 | Gas Operator | Oct 2011 |
| 561 | Wentworth Energy, Inc. | Palestine, TX 75801 | Oil & Gas Operator | Jun 2009 |
| 562 | Wentworth Operating Company | Oklahoma City, OK 73162-1863 | Oil & Gas Operator | Nov 2025 |
| 563 | Wentworth Production Company | | Oil & Gas Operator | Aug 1985 |
| 564 | Werner Oil Farm | Warren, PA 16365-3608 | Oil & Gas Operator | Dec 2024 |
| 565 | Werner Oil, Inc. | Borger, TX 79008 | Oil & Gas Operator | Sep 1996 |
| 566 | Werner Roland L | | Gas Operator | Nov 1992 |
| 567 | Wernette, Louis J. | Hondo, TX 78861 | Oil & Gas Operator | Sep 2023 |
| 568 | Werth Exploration Trust | | Oil Operator | Dec 2013 |
| 569 | Wes Oil & Gas LLC | Clarks Mills, PA 16114-1912 | Gas Operator | Dec 2024 |
| 570 | Wes Pro, Inc. | Jacksboro, TX 76458 | Oil Operator | Jan 2013 |
| 571 | Wes-Mor Drilling, Inc. | Graham, TX 76450 | Oil & Gas Operator | Dec 2025 |
| 572 | Wes-Mor Oil & Gas, Inc. | Graham, TX 76450 | Oil & Gas Operator | Apr 1994 |
| 573 | Wes-Tex Drilling Company | Abilene, TX 79604 | Oil & Gas Operator | Jan 2000 |
| 574 | Wes-Tex Oil Co. (I) | Bangs, TX 76823 | Oil & Gas Operator | Dec 2025 |
| 575 | Wesco Operating Inc | Casper, WY 82602 | Oil & Gas Operator | Nov 2025 |
| 576 | Wesco Production LLC | | Oil & Gas Operator | Jun 2025 |
| 577 | Wescor LLC | Hartville, OH 44632 | Oil & Gas Operator | Dec 2024 |
| 578 | Wesgra Corporation | Mexican Hat, UT 84531 | Oil & Gas Operator | Nov 2025 |
| 579 | Wesla Oil & Gas Co., Inc. | | Oil & Gas Operator | Jun 2001 |
| 580 | Wespac Energy, LLC | San Antonio, TX 78217 | Oil & Gas Operator | Dec 2019 |
| 581 | Wessel Oil And Gas | Cushing, OK 74023-9580 | Oil & Gas Operator | Mar 2015 |
| 582 | Wessely Energy Company | Dallas, TX 75206 | Oil & Gas Operator | May 2001 |
| 583 | Wessely Energy Corporation | | Oil & Gas Operator | Feb 1989 |
| 584 | West 40 Production | Ness City, KS 67560 | Oil Operator | Apr 1998 |
| 585 | West American Energy Corporation | | Oil & Gas Operator | Nov 2025 |
| 586 | West Barrytown Services, LLC | Gilbertown, AL 36908 | Oil & Gas Operator | Mar 2020 |
| 587 | West Bay Exploration Company | Muenster, TX 76252 | Oil & Gas Operator | Nov 2025 |
| 588 | West Chase Count | | Gas Operator | Aug 1981 |
| 589 | West Co., The | Wichita Falls, TX 76307 | Oil & Gas Operator | Jun 2016 |
| 590 | West Coast Oil Company | | Oil Operator | Dec 1996 |
| 591 | West Coast Operators Inc. | | Oil & Gas Operator | Oct 2025 |
| 592 | West Delta Oil Co. | | Oil & Gas Operator | Jul 2000 |
| 593 | West Energy Operating LLC | | Oil & Gas Operator | Oct 2025 |
| 594 | West Fox SWD LLC | Ratliff City, OK 73481 | Oil Operator | Nov 2025 |
| 595 | West Gas Inc | | Oil & Gas Operator | Dec 2017 |
| 596 | West Hopkins Petroleum Co LP | | Oil & Gas Operator | Nov 2025 |
| 597 | West Inland Energy, Inc. | Fort Worth, TX 76179 | Oil & Gas Operator | Dec 2025 |
| 598 | West Kansas Oil | | Oil Operator | Jul 1992 |
| 599 | West Kansas Oil Corporation | Oberlin, KS 67749 | Oil Operator | Aug 1998 |
| 600 | West Largo Corp | Tulsa, OK 74137 | Oil & Gas Operator | Sep 2023 |