| 601 | St James Energy Operating Inc | | Oil & Gas Operator | Aug 2013 |
| 602 | Standley* Robert K Dba Otis Energy | | Oil Operator | Jan 2023 |
| 603 | Starlight Resources LLC | | Oil & Gas Operator | Jun 2006 |
| 604 | Stehle Oil Company | | Oil Operator | Jun 2021 |
| 605 | Stelbar Oil Corporation, Inc. | Wichita, KS 67206 | Oil & Gas Operator | Dec 2023 |
| 606 | Stephens Energy Company LLC | | Oil & Gas Operator | Jun 2012 |
| 607 | Stewart Petroleum Corporation | Greenwood VIllage, CO 80111 | Oil & Gas Operator | Dec 2023 |
| 608 | Stone Energy Corporation | Denver, CO 80202-2828 | Oil & Gas Operator | Oct 2014 |
| 609 | Strachan Exploration Inc | Englewood, CO 80112 | Oil & Gas Operator | Feb 2024 |
| 610 | Stroud Oil Properties, Inc. | Fort Worth, TX 76102 | Oil & Gas Operator | May 2013 |
| 611 | Summit Oil & Gas LLC | | Oil & Gas Operator | Feb 2024 |
| 612 | Summit Operating LLC | Boulder, CO 80301 | Oil & Gas Operator | Feb 2024 |
| 613 | Sunburst, Inc. | Wheat Ridge, CO 80033 | Oil & Gas Operator | Feb 2024 |
| 614 | Sundance Energy Inc | Denver, CO 80202 | Oil & Gas Operator | Jul 2014 |
| 615 | Sundance Resources, Inc. | Rio VIsta, TX 76093 | Oil & Gas Operator | Mar 2012 |
| 616 | Swepi LP | Houston, TX 77079 | Oil & Gas Operator | Jul 2020 |
| 617 | Swevco-Sabw LLC | Houston, TX 77002 | Oil & Gas Operator | Feb 2024 |
| 618 | Swift Beef Company | | Oil & Gas Operator | May 2006 |
| 619 | SWN Production Company, LLC | Spring, TX 77391 | Oil & Gas Operator | Feb 2024 |
| 620 | Synergy Operating LLC | Farmington, NM 87499 | Oil & Gas Operator | Feb 2024 |
| 621 | Synergy Resources Corporation | | Oil & Gas Operator | Oct 2022 |
| 622 | T P Operating LLC | | Oil & Gas Operator | Nov 1999 |
| 623 | Tabula Rasa Energy, LLC | Allen, TX 75013 | Oil & Gas Operator | Dec 2020 |
| 624 | Tamco Drilling Inc | | Oil & Gas Operator | Apr 2003 |
| 625 | Tarpon Oil Company | Fort Worth, TX 76107 | Oil & Gas Operator | Mar 2017 |
| 626 | Tbi Production Company | Lakewood, CO 80228 | Oil & Gas Operator | Oct 2004 |
| 627 | Terra Exploration & Production Co. Inc. | | Oil & Gas Operator | Dec 2009 |
| 628 | Texaco Expl. And Prod. Inc. | Houston, TX 77236 | Oil & Gas Operator | Dec 2023 |
| 629 | Texakoma Operating, L.P. | Plano, TX 75024 | Oil & Gas Operator | Apr 2024 |
| 630 | Texas American Resources Company | Austin, TX 78701 | Oil & Gas Operator | Apr 2024 |
| 631 | Texas Tea Of Colorado LLC Dba Texas Tea LLC | | Oil & Gas Operator | Jun 2021 |
| 632 | The Houston Exploration Company | Houston, TX 77002 | Oil & Gas Operator | Apr 2017 |
| 633 | The Termo Company | Long Beach, CA 90801 | Oil & Gas Operator | Feb 2024 |
| 634 | Thomas L Spring LLC | | Oil & Gas Operator | Feb 2024 |
| 635 | Thomas Operating Company Inc | Greeley, CO 80634 | Oil & Gas Operator | Aug 2008 |
| 636 | Thompson & James Cleo Thompson, Jr.* & J Cleo | | Oil & Gas Operator | Jan 2010 |
| 637 | Thorofare Resources, Inc | | Oil & Gas Operator | May 2011 |
| 638 | Three Forks Resources LLC | Wheat Ridge, CO 80033 | Oil & Gas Operator | Apr 2024 |
| 639 | Tidal Wave Energy, Inc. | New Castle, PA 16105 | Oil & Gas Operator | Jun 2022 |
| 640 | Tigges Oil LLC | | Oil & Gas Operator | Dec 2022 |
| 641 | Timber Creek Operating LLC | Granbury, TX 76049 | Oil & Gas Operator | Apr 2024 |
| 642 | Timberline Energy Inc | Franklin, PA 16323-0269 | Oil & Gas Operator | Jun 2018 |
| 643 | Timka Resources LTD | | Oil & Gas Operator | Feb 2024 |
| 644 | Tindall Operating Company | Englewood, CO 80112 | Oil & Gas Operator | Feb 2024 |
| 645 | Tipperary Oil & Gas Corp | Denver, CO 80202 | Oil & Gas Operator | May 2014 |
| 646 | Tom Brown Inc | Denver, CO 80202 | Oil & Gas Operator | Dec 2004 |
| 647 | Tom Fenno Production LLC | | Oil Operator | Nov 2019 |
| 648 | Top Operating Company | | Oil & Gas Operator | Oct 2022 |
| 649 | Trend Exploration Company | Midland, TX 79701 | Oil & Gas Operator | Mar 2008 |
| 650 | Trinity Bay Oil & Gas, Inc. | Lubbock, TX 79416 | Oil & Gas Operator | Apr 2024 |
| 651 | Trinity Energy Corp | Gibsonia, PA 15044-9106 | Oil & Gas Operator | Dec 2007 |
| 652 | Trinity Energy Resources Inc | Houston, TX 77079 | Oil & Gas Operator | Aug 2005 |
| 653 | Triple R Oil Co | | Oil & Gas Operator | Jun 2002 |
| 654 | Trousil & Associates, Inc. | Steamboat SPG, CO 80477 | Oil & Gas Operator | Dec 2006 |
| 655 | True Oil LLC | Casper, WY 82602 | Oil & Gas Operator | Mar 2024 |
| 656 | Tudex Petroleum Inc | | Oil & Gas Operator | Sep 2019 |
| 657 | Twin Arrow Inc | Rangely, CO 81648 | Oil & Gas Operator | Sep 2009 |
| 658 | Tyler Rockies Exploration LTD | Tyler, TX 75710-0119 | Oil & Gas Operator | Feb 2024 |
| 659 | U S Department Of Energy | | Oil & Gas Operator | Apr 1999 |
| 660 | Unioil | Denver, CO 80203 | Oil & Gas Operator | Jun 2012 |
| 661 | Union Oil Co Of California | Midland, TX 79706 | Oil & Gas Operator | Jan 2022 |
| 662 | Union Pacific Resources Co. | Fort Worth, TX 76101 | Oil & Gas Operator | Sep 2002 |
| 663 | Unit Petroleum Company | Tulsa, OK 74170 | Oil & Gas Operator | Apr 2024 |
| 664 | United States Exploration, Inc. | Denver, CO 80802 | Oil & Gas Operator | Jun 2009 |
| 665 | Universal Resources Corp. | Salt Lake Cty, UT 84145 | Oil & Gas Operator | Jan 2000 |
| 666 | Upland Exploration LLC | | Oil & Gas Operator | Feb 2024 |
| 667 | Ursa Operating Company LLC | Denver, CO 80265 | Oil & Gas Operator | Dec 2020 |
| 668 | Valkyrie Operating LLC | Denver, CO 80202 | Oil & Gas Operator | Mar 2024 |
| 669 | Valley Operating Inc | Denver, CO 80218-3633 | Oil & Gas Operator | Jan 2004 |
| 670 | Vanguard Operating, LLC | Houston, TX 77057 | Oil & Gas Operator | Feb 2021 |
| 671 | Vanguard Permian LLC | Houston, TX 77057 | Oil & Gas Operator | Nov 2018 |
| 672 | Vaquero Energy Inc | Bakersfield, CA 93309 | Oil & Gas Operator | May 2023 |
| 673 | Vastar Resources Inc | Houston, TX 77253 | Oil & Gas Operator | Dec 2023 |
| 674 | Vecta Oil & Gas LTD | Dallas, TX 75235 | Oil & Gas Operator | Feb 2024 |
| 675 | Venoco, Inc. | Houston, TX 77002 | Oil & Gas Operator | Mar 2008 |
| 676 | Verdad Oil & Gas Corporation | Dallas, TX 75235 | Oil & Gas Operator | Apr 2024 |
| 677 | Verdad Resources LLC | | Oil & Gas Operator | Feb 2024 |
| 678 | Virtex Petroleum Company, Inc. | Corpus Chrsti, TX 78477 | Oil & Gas Operator | Jan 2008 |
| 679 | Vision Energy LLC | Houston, TX 77002 | Oil & Gas Operator | Feb 2024 |
| 680 | Vista Operating Inc | | Oil & Gas Operator | Dec 2014 |
| 681 | Visual Optics Inc | | Oil Operator | Dec 2012 |
| 682 | Vitruvian Exploration LLC | The Woodlands, TX 77380 | Oil & Gas Operator | May 2016 |
| 683 | Voyager Exploration Inc | Denver, CO 80202 | Oil & Gas Operator | May 2006 |
| 684 | Walker Oil & Gas Co LLC* Keith F | | Oil & Gas Operator | Jun 2011 |
| 685 | Wallace Oil & Gas Inc | Oklahoma City, OK 73156 | Oil & Gas Operator | Apr 2024 |
| 686 | Walsh Production Inc | | Oil & Gas Operator | Nov 2008 |
| 687 | Wapiti Operating, LLC | Houston, TX 77043 | Oil & Gas Operator | Apr 2024 |
| 688 | Ward & Son* Alfred | | Oil & Gas Operator | Jun 2023 |
| 689 | Ward Petroleum Corporation | Enid, OK 73702 | Oil & Gas Operator | Jan 2024 |
| 690 | Wbi Production | | Gas Operator | May 2002 |
| 691 | Wellington Operating Company | | Oil & Gas Operator | Feb 2024 |
| 692 | Wellstar Corporation | Northglenn, CO 80233 | Oil & Gas Operator | Feb 2024 |
| 693 | Wesco Operating, Inc. | Casper, WY 82602 | Oil & Gas Operator | Mar 2024 |
| 694 | West Texas Operating Co LLC D/B/A Xtreme Energy Co | Victoria, TX 77902-2326 | Oil & Gas Operator | Feb 2024 |
| 695 | Westech Energy Corporation | Denver, CO 80237 | Oil & Gas Operator | Mar 2011 |
| 696 | Western Gas Resources Inc | Denver, CO 80202-1955 | Oil & Gas Operator | Dec 2007 |
| 697 | Western Gas Resources-Sand Wash Inc | | Oil & Gas Operator | Feb 2008 |
| 698 | Western Interior Energy Inc. | Denver, CO 80202 | Oil & Gas Operator | Jul 2020 |
| 699 | Western Operating Company | Denver, CO 80204 | Oil & Gas Operator | Jan 2024 |
| 700 | Westgate Oil Company, Inc. | Eureka, KS 67045 | Oil Operator | Feb 2024 |