| 501 | Resolute Wyoming Inc | Denver, CO 80203 | Oil & Gas Operator | May 2018 |
| 502 | Resource Oil And Gas, LLC | Oklahoma City, OK 73114 | Oil & Gas Operator | Apr 2026 |
| 503 | Revelation Resources | Cypress, TX 77410-2578 | Oil & Gas Operator | Jan 2026 |
| 504 | Richard W Thompson Inc | Plano, TX 75075 | Oil & Gas Operator | Jul 2019 |
| 505 | Ricks Expl Acquisition Corp | Oklahoma City, OK 73102 | Oil & Gas Operator | Jan 2004 |
| 506 | Ricks Exploration Co | Oklahoma City, OK 73112 | Oil & Gas Operator | Mar 2015 |
| 507 | Riviera Operating, LLC | Houston, TX 77002 | Oil & Gas Operator | Feb 2026 |
| 508 | RKK Production Company | Mustang, OK 73064 | Oil & Gas Operator | Feb 2026 |
| 509 | RKR Exploration Inc | Seminole, OK 74868 | Oil & Gas Operator | Feb 2026 |
| 510 | Rock Creek Resources LLC | Englewood, CO 80112 | Oil & Gas Operator | Dec 2021 |
| 511 | Roff Operating Company LLC | Houston, TX 77002 | Oil & Gas Operator | Apr 2026 |
| 512 | Rosetta Resources Operating LP | San Antonio, TX 78216 | Oil & Gas Operator | Apr 2026 |
| 513 | RTC Resources, LLP | Weatherford, OK 73096 | Oil & Gas Operator | Apr 2026 |
| 514 | Rupe Oil Company Inc | Wichita, KS 67278 | Oil & Gas Operator | Dec 2025 |
| 515 | Rush-Andrus Engineering | Royse City, TX 75189-1210 | Oil & Gas Operator | Feb 2022 |
| 516 | Russell D Meloy Oil & Gas Co | Enid, OK 73703-1623 | Oil & Gas Operator | Feb 2026 |
| 517 | S & S Star Operating, LLC | Oklahoma City, OK 73101 | Oil & Gas Operator | Mar 2026 |
| 518 | S A C Operating Inc | Woodward, OK 73802-1749 | Oil & Gas Operator | Jan 1999 |
| 519 | Samedan Oil Corporation | Houston, TX 77067 | Oil & Gas Operator | Dec 2019 |
| 520 | Samson Hydrocarbons Company | Tulsa, OK 74103 | Oil & Gas Operator | Nov 2016 |
| 521 | Samson Resources Company | Tulsa, OK 74103 | Oil & Gas Operator | Jan 2026 |
| 522 | Sand Creek Resources LLC | Woodward, OK 73801-5222 | Oil & Gas Operator | Feb 2026 |
| 523 | Sand Point LLC | Oklahoma City, OK 73132 | Oil & Gas Operator | Dec 2020 |
| 524 | Sandridge Energy, Inc. | Oklahoma City, OK 73102 | Oil & Gas Operator | May 2018 |
| 525 | Sandridge Exploration And Production LLC | Oklahoma City, OK 73104 | Oil & Gas Operator | Apr 2026 |
| 526 | Santa Fe Energy Company | Midland, TX 79701 | Oil & Gas Operator | Dec 2015 |
| 527 | Santa Fe Minerals, Inc. | Dallas, TX 75240 | Oil & Gas Operator | Sep 2013 |
| 528 | Santa Fe-Andover Oil Co | Tulsa, OK 74172 | Oil & Gas Operator | Sep 2000 |
| 529 | Scambler Energy Group LTD Co | Colony, OK 73021 | Oil & Gas Operator | Feb 2026 |
| 530 | Schmid Properties, Inc. | Hico, TX 76457 | Oil & Gas Operator | Apr 2026 |
| 531 | Schonwald Supply Company | Oklahoma City, OK 73101-1571 | Oil & Gas Operator | May 1999 |
| 532 | Seagull Energy E & P Inc | Houston, TX 77002 | Oil & Gas Operator | Jan 2015 |
| 533 | Seagull Mid-South Inc | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 534 | Seagull Midcon Inc. | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 535 | Seal Exploration, Inc. | Dallas, TX 75201 | Oil & Gas Operator | Dec 2006 |
| 536 | Search Drilling Company | Houston, TX 77010 | Oil & Gas Operator | Feb 2001 |
| 537 | Shale Properties LLC | Kingfisher, OK 73750 | Oil Operator | Aug 2023 |
| 538 | Shar Alan Oil Company | | Oil & Gas Operator | Oct 2005 |
| 539 | Sheridan Production Company, LLC | Houston, TX 77056 | Oil & Gas Operator | Jan 2026 |
| 540 | Sidwell Oil & Gas, Inc. | Amarillo, TX 79105 | Oil & Gas Operator | Sep 2014 |
| 541 | Silver Pines Energy Corp. | Houston, TX 77005 | Oil & Gas Operator | Feb 2026 |
| 542 | Skycap Energy, LLC | Oklahoma City, OK 73118 | Oil & Gas Operator | Feb 2026 |
| 543 | Slawson Exploration Company Inc | Oklahoma City, OK 73102 | Oil & Gas Operator | Apr 2026 |
| 544 | SM Energy Company | Midland, TX 79707 | Oil & Gas Operator | Apr 2026 |
| 545 | Snyder Oil Company | Fort Worth, TX 76102 | Oil & Gas Operator | Mar 2015 |
| 546 | Snyder Oil Corporation | Houston, TX 77024 | Oil & Gas Operator | Mar 2008 |
| 547 | Snyder Partners | Cody, WY 82414 | Oil & Gas Operator | Jan 2026 |
| 548 | Sooner Oil & Gas LLC | Fairview, OK 73737-1806 | Oil & Gas Operator | Feb 2026 |
| 549 | Sorrels J R Dba Cheyenne Oil Properties | Ponca City, OK 74601 | Oil & Gas Operator | Jul 2022 |
| 550 | South Forty Inc (The) | Laverne, OK 73848 | Oil & Gas Operator | Mar 2015 |
| 551 | Southern Star Central Gas Pipeline Inc | Owensboro, KY 42301 | Oil & Gas Operator | Jan 2026 |
| 552 | Southland Royalty Company | Houston, TX 77210 | Oil & Gas Operator | Sep 2011 |
| 553 | Southwest Energy LP | Tulsa, OK 74136 | Oil & Gas Operator | Dec 2025 |
| 554 | Southwest Royalties, Inc. | Midland, TX 79710 | Oil & Gas Operator | Apr 2026 |
| 555 | Sparks Resources Inc | Bristow, OK 74010 | Oil & Gas Operator | Feb 2026 |
| 556 | Special Energy Corp. | Stillwater, OK 74076 | Oil & Gas Operator | Apr 2026 |
| 557 | Spess Oil Company Inc | Cleveland, OK 74020-4617 | Oil & Gas Operator | Feb 2026 |
| 558 | Spindletop Oil & Gas Co. | Dallas, TX 75230 | Oil & Gas Operator | Apr 2026 |
| 559 | St. Mary Operating Company | Denver, CO 80203 | Oil & Gas Operator | Mar 2019 |
| 560 | Staghorn Energy, LLC | Tulsa, OK 74103 | Oil & Gas Operator | Jan 2026 |
| 561 | Staghorn Petroleum II LLC | Tulsa, OK 74103-3500 | Oil & Gas Operator | Feb 2026 |
| 562 | Staghorn Resources, LLC | Tulsa, OK 74103 | Oil & Gas Operator | Apr 2015 |
| 563 | Stargas Co | Tulsa, OK 74136-5407 | Oil & Gas Operator | Aug 2013 |
| 564 | Statex Petroleum Inc | Dallas, TX 75229 | Oil & Gas Operator | Dec 2000 |
| 565 | Stephen Michael Inc | Midwest City, OK 73130-5200 | Oil & Gas Operator | Oct 2015 |
| 566 | Stephens Exploration, Inc. | Dallas, TX 75367 | Oil & Gas Operator | Feb 2026 |
| 567 | Stephens Production Company | The Woodlands, TX 77381 | Oil & Gas Operator | Feb 2026 |
| 568 | Stevenson Oil Co | Houston, TX 77002 | Oil & Gas Operator | Mar 2025 |
| 569 | Stoneriver Energy, LLC | Lubbock, TX 79424 | Oil & Gas Operator | Apr 2026 |
| 570 | Strat Land Exploration Company | Tulsa, OK 74103 | Oil & Gas Operator | Jan 2026 |
| 571 | Stumpff Paul | Bartlesville, OK 74006-3426 | Oil & Gas Operator | Mar 2015 |
| 572 | Sullivan And Company LLC | Tulsa, OK 74119 | Oil & Gas Operator | Jan 2026 |
| 573 | Sundown Energy LP | Dallas, TX 75248 | Oil & Gas Operator | Apr 2026 |
| 574 | Sundown Energy, Inc. | Dallas, TX 75240 | Oil & Gas Operator | May 2025 |
| 575 | Sunterra Energy Corporation | Tulsa, OK 74103 | Oil & Gas Operator | Dec 2009 |
| 576 | Sweetwater Exploration LLC | Norman, OK 73069-5636 | Oil & Gas Operator | Jan 2026 |
| 577 | Swift Energy Company | Houston, TX 77060 | Oil & Gas Operator | Mar 2021 |
| 578 | SWN Production LLC | Spring, TX 77389-4954 | Oil & Gas Operator | Feb 2022 |
| 579 | Sydson D'Oro Exploration Co. | Houston, TX 77079 | Oil & Gas Operator | Jan 1992 |
| 580 | Tapstone Energy LLC | Oklahoma City, OK 73101 | Oil & Gas Operator | Feb 2026 |
| 581 | Tbi Exploration Inc | Englewood, CO 801556525 | Oil & Gas Operator | Jun 2011 |
| 582 | Tcina Inc | Seminole, OK 74868 | Oil & Gas Operator | May 2023 |
| 583 | Tekenergy Inc | Oklahoma City, OK 73112 | Oil & Gas Operator | Mar 2015 |
| 584 | Tema Oil Company | Amarillo, TX 79101 | Oil & Gas Operator | Jun 2009 |
| 585 | Temex Energy Inc | Oklahoma City, OK 73101 | Oil & Gas Operator | Feb 2002 |
| 586 | Tenneco Oil Company | Oklahoma City, OK 73125 | Oil & Gas Operator | Dec 2025 |
| 587 | Teocalli Exploration LLC | Kingfisher, OK 73750 | Oil & Gas Operator | Feb 2026 |
| 588 | Tesoro Expl. & Prod. Company | San Antonio, TX 78216 | Gas Operator | Sep 2010 |
| 589 | Tex-Ok Energy, Limited Partnership | Cody, WY 82414 | Oil & Gas Operator | Feb 2026 |
| 590 | Tex-Star Production | Dallas, TX 75206 | Oil & Gas Operator | Feb 2026 |
| 591 | Tex/Con Oil & Gas Company | Houston, TX 77074 | Oil & Gas Operator | Feb 2001 |
| 592 | Texaco Exploration & Prod Inc | Houston, TX 77236 | Oil & Gas Operator | Dec 2025 |
| 593 | Texaco Inc | Kingfisher, OK 73750 | Oil & Gas Operator | Dec 2017 |
| 594 | Texas Meridian Operating Co. Inc | Houston, TX 77079 | Oil & Gas Operator | Oct 1993 |
| 595 | Texas Mineral Group | Midland, TX 79705 | Oil & Gas Operator | Aug 2013 |
| 596 | Texas Oil & Gas Corporation | Dallas, TX 75201 | Oil & Gas Operator | Feb 2001 |
| 597 | TGX Corporation | Houston, TX 77002 | Oil & Gas Operator | Sep 2004 |
| 598 | Three D Resources Inc | Liberal, KS 67905 | Oil & Gas Operator | Dec 2025 |
| 599 | Tide West Oil Company | Tulsa, OK 74136 | Oil & Gas Operator | Mar 2021 |
| 600 | Tidemark Exploration | Tulsa, OK 74170 | Oil & Gas Operator | May 2005 |