| 601 | Rme Petroleum Company | Houston, TX 77251 | Oil & Gas Operator | Nov 2016 |
| 602 | Rmor Production | Kilgore, TX 75662 | Oil Operator | May 2025 |
| 603 | Road Oil Sales Inc. | Tyler, TX 75711 | Oil Operator | Dec 1984 |
| 604 | Robbins Energy, Inc. | Longview, TX 75606 | Oil & Gas Operator | Sep 1994 |
| 605 | Robbins Petroleum Corp. | Longview, TX 75606 | Oil & Gas Operator | Sep 1994 |
| 606 | Robertson Resources, Inc. | Midland, TX 79708 | Oil & Gas Operator | May 2025 |
| 607 | Robertson-Bryce Management, LLC | Tyler, TX 75701 | Oil & Gas Operator | May 2025 |
| 608 | Robinett Resources Inc. | Longview, TX 75601 | Oil & Gas Operator | Dec 1999 |
| 609 | Robinson Operating Company | Abilene, TX 79604 | Oil & Gas Operator | Aug 2012 |
| 610 | Roc Operating, Inc. | Plano, TX 75093 | Oil & Gas Operator | Oct 2008 |
| 611 | Rockcliff Energy Operating LLC | Houston, TX 77002 | Oil & Gas Operator | May 2025 |
| 612 | Rodessa Management, Inc. | Longview, TX 75606 | Oil & Gas Operator | May 1995 |
| 613 | Roil Mineral & Land Co. | Dallas, TX 75379 | Oil & Gas Operator | May 2025 |
| 614 | Rojo Burro Petroleo & Gas | Kilgore, TX 75662 | Oil & Gas Operator | Aug 2007 |
| 615 | Rollert Co., Inc., The | Luling, TX 78648 | Oil & Gas Operator | Nov 2000 |
| 616 | Roosth & Genecov Production Co. | Tyler, TX 75710 | Oil & Gas Operator | Aug 2003 |
| 617 | Roosth Production Co. | Tyler, TX 75711 | Oil & Gas Operator | May 2025 |
| 618 | Roseland Oil & Gas Inc | Rockwall, TX 75087 | Oil & Gas Operator | Feb 2003 |
| 619 | Rowan, Al | Van, TX 75790 | Oil & Gas Operator | Apr 2021 |
| 620 | Royal Petroleum Corp. | Dallas, TX 75229 | Oil & Gas Operator | Jan 2025 |
| 621 | RTD Resources, LLC | Kilgore, TX 75663 | Oil & Gas Operator | May 2025 |
| 622 | Rudman Partnership, The | Dallas, TX 75201 | Oil & Gas Operator | Dec 2014 |
| 623 | Rusk Co. Well Service Co., Inc. | Kilgore, TX 75663 | Oil & Gas Operator | May 2025 |
| 624 | Rusk Energy Management, LLC | Houston, TX 77002 | Oil & Gas Operator | Feb 2008 |
| 625 | Rwa, LLC | Boyd, TX 76023 | Oil & Gas Operator | May 2025 |
| 626 | S N D Energy Company, Inc. | Kilgore, TX 75662 | Oil & Gas Operator | May 2025 |
| 627 | S.E.D.I. | Kilgore, TX 75663 | Oil & Gas Operator | Apr 2015 |
| 628 | Sabine Oil & Gas Corporation | Houston, TX 77002 | Oil & Gas Operator | May 2025 |
| 629 | Sabine Oil & Gas LLC | Houston, TX 77002 | Oil & Gas Operator | Dec 2017 |
| 630 | Sabine Pipe & Supply Co. | Kilgore, TX 75663 | Oil & Gas Operator | Sep 2004 |
| 631 | Sabine Pipe, Inc. | Kilgore, TX 75663 | Oil & Gas Operator | May 2025 |
| 632 | Sabine Syndicate No. 1 | Longview, TX 75606 | Oil & Gas Operator | May 2025 |
| 633 | Samedan Oil Corporation | Houston, TX 77067 | Oil & Gas Operator | Dec 2019 |
| 634 | Samson Hydrocarbons Company | Tulsa, OK 74103 | Oil & Gas Operator | Nov 2016 |
| 635 | Samson Lone Star LP | Tulsa, OK 74103 | Oil & Gas Operator | Jun 2007 |
| 636 | Samson Lone Star, LLC | Tulsa, OK 74103 | Oil & Gas Operator | May 2025 |
| 637 | Samson Resources Company | Tulsa, OK 74103 | Oil & Gas Operator | Feb 2025 |
| 638 | Sanders, Larry E. Trustee | Longview, TX 75606 | Oil & Gas Operator | May 2025 |
| 639 | Sandridge Exploration And Production LLC | Oklahoma City, OK 73104 | Oil & Gas Operator | May 2025 |
| 640 | Sandridge Onshore, LLC | Houston, TX 77010 | Oil & Gas Operator | Jun 2014 |
| 641 | Santa Fe Energy Resources, Inc. | Houston, TX 77024 | Oil & Gas Operator | Mar 2008 |
| 642 | Scheriger Production | Graham, TX 76450 | Oil & Gas Operator | Jun 2006 |
| 643 | Schlachter, David A. | Dallas, TX 75225 | Oil & Gas Operator | Apr 2015 |
| 644 | Scout Energy Management LLC | Dallas, TX 75240 | Oil & Gas Operator | May 2025 |
| 645 | Scythian, LTD. | Midland, TX 79701 | Oil & Gas Operator | Dec 2020 |
| 646 | SDG Operating Company, Inc | Tyler, TX 75701 | Oil & Gas Operator | May 2025 |
| 647 | Seagull Energy E & P Inc | Houston, TX 77002 | Oil & Gas Operator | Jan 2015 |
| 648 | Seagull Mid-South Inc | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 649 | Secondary Oil Corp., Inc. | Austin, TX 78750 | Oil Operator | Apr 1999 |
| 650 | Sei Operating, LLC | Mandeville, LA 70471 | Oil & Gas Operator | May 2025 |
| 651 | Shappell Oil Company, L.L.C. | Kilgore, TX 75663 | Oil & Gas Operator | May 2025 |
| 652 | Shelby Production Co. | Kilgore, TX 75663 | Oil & Gas Operator | Mar 2009 |
| 653 | Shell Western E&P Inc. | Houston, TX 77001 | Oil & Gas Operator | May 2011 |
| 654 | Sheridan Production Co III, LLC | Houston, TX 77056 | Oil & Gas Operator | May 2025 |
| 655 | Sheridan Production Company, LLC | Houston, TX 77056 | Oil & Gas Operator | Feb 2025 |
| 656 | Shidler, Mark L., Inc. | Houston, TX 77055 | Oil & Gas Operator | May 2025 |
| 657 | Shoco Production LLC | Kilgore, TX 75663 | Oil & Gas Operator | May 2025 |
| 658 | Shoco Production, L.P. | Kilgore, TX 75663 | Oil & Gas Operator | May 2020 |
| 659 | Shore Production Co. | Longview, TX 75604 | Oil & Gas Operator | Aug 2005 |
| 660 | Sigmon Production Company, Inc. | Longview, TX 75608 | Oil & Gas Operator | Dec 2013 |
| 661 | Signal Oil Company, LLC | Kilgore, TX 75663 | Oil & Gas Operator | May 2025 |
| 662 | Sikes Operating, Inc. | Tyler, TX 75711 | Oil & Gas Operator | Jun 2003 |
| 663 | Silver Oak Operating, Inc. | Longview, TX 75601 | Oil & Gas Operator | Dec 2009 |
| 664 | Siroco Operating Co., Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Apr 2010 |
| 665 | Sklar & Phillips Oil Co. | Shreveport, LA 71101 | Oil & Gas Operator | Dec 2000 |
| 666 | Slant Operating, LLC | Lafayette, LA 70503 | Oil & Gas Operator | May 2025 |
| 667 | SM Energy Company | Midland, TX 79707 | Oil & Gas Operator | May 2025 |
| 668 | Smal Energy Corp | Tyler, TX 75710 | Oil & Gas Operator | Oct 1995 |
| 669 | Smith Resources, Inc. | Marshall, TX 75671 | Oil & Gas Operator | May 2025 |
| 670 | Smith, E. J. | Fort Worth, TX 76137 | Oil & Gas Operator | May 2025 |
| 671 | Smith, E.N. III Energy Corp. | Marshall, TX 75671 | Oil & Gas Operator | Sep 2006 |
| 672 | Smith, R. E. Interests, Inc. | Houston, TX 77027 | Oil & Gas Operator | Mar 1998 |
| 673 | SND Operating, L.L.C. | Kilgore, TX 75663 | Oil & Gas Operator | May 2025 |
| 674 | Sojitz Energy Venture, Inc. | Houston, TX 77042 | Oil & Gas Operator | Feb 2018 |
| 675 | Sojourner Drilling Corporation | Abilene, TX 79604 | Oil & Gas Operator | May 2025 |
| 676 | Sonat Exploration Co. | Houston, TX 77251 | Oil & Gas Operator | Dec 2021 |
| 677 | Sonat Exploration Company -Tyler | Houston, TX 77251 | Oil & Gas Operator | Dec 1999 |
| 678 | Sonora Petroleum Corp. | Austin, TX 78734 | Oil & Gas Operator | May 2025 |
| 679 | Southern Bay Operating, L.L.C. | Houston, TX 77002 | Oil & Gas Operator | Jun 2013 |
| 680 | Southlake Operating LLC | Weatherford, TX 76086 | Oil & Gas Operator | May 2025 |
| 681 | Southwest Operating, Inc.-Tyler | Tyler, TX 75701 | Oil & Gas Operator | May 2025 |
| 682 | Speegle Oil And Gas Company | Longview, TX 75605 | Oil & Gas Operator | May 2025 |
| 683 | Spindletop Oil & Gas Co. | Dallas, TX 75230 | Oil & Gas Operator | May 2025 |
| 684 | St. Mary Land & Exploration Co | Denver, CO 80201 | Oil & Gas Operator | Jun 2010 |
| 685 | Staley Oil Company | Wichita Falls, TX 76308 | Oil & Gas Operator | Jan 2000 |
| 686 | Stephens, Glynn | Overton, TX 75684 | Oil & Gas Operator | Oct 2001 |
| 687 | Stevens & Tull, Inc. | Midland, TX 79702 | Oil & Gas Operator | Jun 2000 |
| 688 | Stonewall Production Company Inc | Tyler, TX 75702 | Oil & Gas Operator | Aug 2009 |
| 689 | Strand Energy, L.C. | Houston, TX 77002 | Oil & Gas Operator | May 2025 |
| 690 | Strebor Oil Co. | Dallas, TX 75225 | Oil & Gas Operator | Jun 1993 |
| 691 | Stroud Energy, LTD. | Fort Worth, TX 76102 | Oil & Gas Operator | Jun 2006 |
| 692 | Stroud Petroleum, Inc. | Shreveport, LA 71162 | Oil & Gas Operator | May 2025 |
| 693 | Subterranean Energy, LLC | Tyler, TX 75705 | Oil & Gas Operator | May 2025 |
| 694 | Summit Energy, Inc. | Littleton, CO 80127 | Oil & Gas Operator | Aug 2013 |
| 695 | Summit Resources MGMT., LLC. | Edmond, OK 73083 | Oil & Gas Operator | May 2025 |
| 696 | Sundance Resources, Inc. | Rio VIsta, TX 76093 | Oil & Gas Operator | Mar 2012 |
| 697 | Sundown Energy LP | Dallas, TX 75248 | Oil & Gas Operator | May 2025 |
| 698 | Superior Royalty, LLC | Lindale, TX 75771 | Oil Operator | May 2025 |
| 699 | Supreme Energy Company, Inc. | Abilene, TX 79601 | Oil & Gas Operator | May 2025 |
| 700 | SW Operating, Inc. | Kilgore, TX 75662 | Oil & Gas Operator | Sep 2000 |