| 501 | Regional Energy Corporation | Temple, TX 76503-1733 | Oil Operator | Mar 1996 |
| 502 | Research Oil Company Inc | Norman, OK 73070-8776 | Oil & Gas Operator | Aug 2019 |
| 503 | RF Operating And Supply Inc | | Oil & Gas Operator | Feb 2013 |
| 504 | Rhoades Oil Co | Tulsa, OK 74136-5575 | Oil & Gas Operator | Aug 2013 |
| 505 | Ric Petroleum, Inc. | Wichita Falls, TX 76307 | Oil & Gas Operator | Aug 2003 |
| 506 | Richard W Thompson Inc | Plano, TX 75075 | Oil & Gas Operator | Jul 2019 |
| 507 | River Valley Oil LLC | Konawa, OK 74849 | Oil Operator | Jun 2025 |
| 508 | Riviera Operating, LLC | Houston, TX 77002 | Oil & Gas Operator | Jul 2025 |
| 509 | Rja Energy LLC | Norman, OK 73069-8224 | Oil & Gas Operator | Jul 2025 |
| 510 | RKR Exploration Inc | Seminole, OK 74868 | Oil & Gas Operator | Jun 2025 |
| 511 | Roadrunner Energy, Inc. | Tulsa, OK 74120 | Oil & Gas Operator | Mar 2015 |
| 512 | Roberson David A | Ada, OK 74821-0008 | Oil & Gas Operator | Jul 2010 |
| 513 | Roberson Oil Company | Houston, TX 77046 | Oil & Gas Operator | Jun 2025 |
| 514 | Robinowitz Oil Company | Tulsa, OK 74136-1429 | Oil & Gas Operator | Feb 2023 |
| 515 | Robson Petroleum Company | Tulsa, OK 74104 | Oil & Gas Operator | Jan 1995 |
| 516 | Rockwell Drilling Company | New York, NY 10013 | Oil & Gas Operator | Dec 2005 |
| 517 | Rodman Petroleum Corp. | Odessa, TX 79768 | Oil & Gas Operator | Jul 2023 |
| 518 | Romine Oil & Gas LTD | Shawnee, OK 74802-3425 | Oil & Gas Operator | Jan 2013 |
| 519 | Ronmar Engineering & Expl Inc | Ada, OK 74820-1402 | Oil Operator | Aug 2013 |
| 520 | Rox Exploration Inc | Norman, OK 73069-6301 | Oil & Gas Operator | Jul 2025 |
| 521 | Roxanna Oil Company | Oklahoma City, OK 73120-2717 | Oil Operator | Aug 2016 |
| 522 | Royal Petroleum Corp. | Dallas, TX 75229 | Oil & Gas Operator | Jan 2025 |
| 523 | Royalty Energy Development LLC | Edmond, OK 73003 | Oil & Gas Operator | Jul 2025 |
| 524 | Roye Realty & Developing Inc | Stigler, OK 74462-0148 | Gas Operator | Dec 2004 |
| 525 | Rumley Robert A & Associates | Tulsa, OK 74135-1907 | Oil Operator | Jun 2025 |
| 526 | Rust Oil Corp. | Fort Worth, TX 76108 | Oil & Gas Operator | Oct 2025 |
| 527 | S & J Operating Company | Wichita Falls, TX 76301 | Oil & Gas Operator | Mar 2015 |
| 528 | S & K Oil Company | Tulsa, OK 74101 | Oil & Gas Operator | Jul 1994 |
| 529 | S & W Engine Supply | Oklahoma City, OK 73107 | Oil Operator | Jun 2003 |
| 530 | S/H Petroleum Corporation | Hennessey, OK 73742-0477 | Oil & Gas Operator | Feb 2016 |
| 531 | Salt Creek Energy Company LLC | Shawnee, OK 74802-1505 | Oil & Gas Operator | Jun 2025 |
| 532 | Samedan Oil Corporation | Houston, TX 77067 | Oil & Gas Operator | Dec 2019 |
| 533 | Samson Resources Company | Tulsa, OK 74103 | Oil & Gas Operator | Jun 2025 |
| 534 | Sandy Petroleum Inc | Shawnee, OK 74801-5634 | Oil & Gas Operator | Jun 2025 |
| 535 | Sanguine Gas Exploration, LLC | Tulsa, OK 74119 | Oil & Gas Operator | Oct 2025 |
| 536 | Sanook Inc | Oklahoma City, OK 73156-0548 | Oil & Gas Operator | Jan 2007 |
| 537 | Santa Fe Minerals, Inc. | Dallas, TX 75240 | Oil & Gas Operator | Sep 2013 |
| 538 | Saqus Oil Co | Oklahoma City, OK 73107 | Oil & Gas Operator | May 2001 |
| 539 | Sasakwa Operating LLC | Oklahoma City, OK 73179-1902 | Oil & Gas Operator | Jun 2025 |
| 540 | Schiff & Jackson Oil Producers | Dallas, TX 75206 | Oil & Gas Operator | Jun 2025 |
| 541 | Schlachter, David A. | Dallas, TX 75225 | Oil & Gas Operator | Apr 2015 |
| 542 | Scissortail Energy LLC | Tulsa, OK 74137-3644 | Oil & Gas Operator | Feb 2015 |
| 543 | Seagull Energy E & P Inc | Houston, TX 77002 | Oil & Gas Operator | Jan 2015 |
| 544 | Seaport Inc | Oklahoma City, OK 73131 | Oil & Gas Operator | Jun 2025 |
| 545 | Sellers Jack B Estate Of | Cleveland, OK 74020 | Oil & Gas Operator | Jun 2025 |
| 546 | Seminole Company (The) | | Oil Operator | Dec 1994 |
| 547 | Seminole Tank Service | Seminole, OK 74818-1587 | Oil & Gas Operator | Jun 2025 |
| 548 | Sentinel Petroleum Inc | Oklahoma City, OK 73102 | Oil & Gas Operator | Feb 2020 |
| 549 | Shannon Petroleum Inc | Tulsa, OK 74136-4603 | Oil & Gas Operator | Oct 2016 |
| 550 | Sharber Billy Jack Operating | Konawa, OK 74849-0071 | Oil & Gas Operator | Mar 2015 |
| 551 | Sharber Don E | Okemah, OK 74859-0322 | Oil Operator | Dec 2018 |
| 552 | Sharber Production Inc | Konawa, OK 74849 | Oil & Gas Operator | Dec 2024 |
| 553 | Sharp Anthony G | Shawnee, OK 74802-1701 | Oil & Gas Operator | Jul 2003 |
| 554 | Signature Exploration Inc. | Shawnee, OK 74804-4130 | Oil & Gas Operator | Mar 2015 |
| 555 | Silver Creek Oil & Gas, LLC | Flower Mound, TX 75022 | Oil & Gas Operator | Oct 2025 |
| 556 | Silver Pines Energy Corp. | Houston, TX 77005 | Oil & Gas Operator | May 2025 |
| 557 | Simco Operating | Shawnee, OK 74804-2501 | Oil Operator | Jan 2013 |
| 558 | Simon Royce & Joyce | Tecumseh, OK 74873-7341 | Oil Operator | Jun 2018 |
| 559 | Singer Oil Co LLC | Hennessey, OK 73742 | Oil & Gas Operator | Jul 2025 |
| 560 | Singer Oil Company | Oklahoma City, OK 73148 | Oil & Gas Operator | May 2025 |
| 561 | Siosi Oil & Gas Company | Tulsa, OK 74170 | Oil & Gas Operator | Nov 2013 |
| 562 | Smith Brothers Enterprises | Ardmore, OK 73402 | Oil Operator | Jul 1998 |
| 563 | Smith Manus L MFG Inc | Oklahoma City, OK 73147 | Oil & Gas Operator | Nov 1998 |
| 564 | Smith Max Dean | Wewoka, OK 74884 | Oil & Gas Operator | May 2025 |
| 565 | SNR Central Oklahoma Operating LLC | Oklahoma City, OK 73116-7906 | Oil Operator | Jun 2025 |
| 566 | SNR Operating, LLC | Nichols Hill, OK 73116 | Oil & Gas Operator | Oct 2025 |
| 567 | Snuffy'S Oilfield Service Inc | Hennessey, OK 73742-6511 | Oil & Gas Operator | Nov 2014 |
| 568 | Sooner Drilling Inc | Shawnee, OK 74802-0037 | Oil & Gas Operator | Jan 2005 |
| 569 | Sooner Pipe & Supply Corp | | Oil & Gas Operator | Nov 2004 |
| 570 | Southland Energy Corporation | Houston, TX 77060 | Oil & Gas Operator | Aug 2022 |
| 571 | Southwest Royalties Inc | Midland, TX 79710 | Oil & Gas Operator | Oct 2025 |
| 572 | SP Energy Development Company | Seattle, WA 98101-3277 | Oil & Gas Operator | Mar 2015 |
| 573 | Special Energy Corporation | Stillwater, OK 74076 | Oil & Gas Operator | Oct 2025 |
| 574 | Spess Oil Company Inc | Cleveland, OK 74020-4617 | Oil & Gas Operator | Jul 2025 |
| 575 | Splawn & Splawn | Saint Louis, OK 74866-0098 | Oil & Gas Operator | Mar 2025 |
| 576 | Stacy Operating LLC | Cushing, OK 74023 | Oil & Gas Operator | Jun 2025 |
| 577 | Staghorn Petroleum II LLC | Tulsa, OK 74103-3500 | Oil & Gas Operator | Jul 2025 |
| 578 | Stalnaker Oil Company | Maud, OK 74854-0295 | Oil Operator | May 2017 |
| 579 | Stark Oil Properties | Asher, OK 74826 | Oil & Gas Operator | Jan 1997 |
| 580 | Sterling Oil Of Okla Inc | Tulsa, OK 74170-2163 | Oil & Gas Operator | Nov 2006 |
| 581 | Stobaugh G B Trust | Oklahoma City, OK 73124 | Oil Operator | Dec 2024 |
| 582 | Stover Company | Tulsa, OK 74152-0786 | Oil & Gas Operator | Jan 2013 |
| 583 | STP Cherokee, Inc. | Oklahoma City, OK 73102 | Oil & Gas Operator | Mar 2014 |
| 584 | STP Newco Inc | Oklahoma City, OK 73102-5641 | Oil & Gas Operator | Jul 2021 |
| 585 | Strat Land Exploration Company | Tulsa, OK 74103 | Oil & Gas Operator | Jun 2025 |
| 586 | Stream Energy, Inc. | Oklahoma City, OK 73102 | Oil & Gas Operator | Jul 2025 |
| 587 | Streamline Oil And Gas Inc | Lindsey, OK 73052 | Oil & Gas Operator | Jul 2025 |
| 588 | Striker Management Co LLC | Shawnee, OK 74801 | Oil & Gas Operator | Jun 2025 |
| 589 | Sullivan & Co. | Tulsa, OK 74114 | Oil & Gas Operator | May 2022 |
| 590 | Sullivan And Company LLC | Tulsa, OK 74119 | Oil & Gas Operator | Jun 2025 |
| 591 | Summit Resources Management LLC | Edmond, OK 73083 | Oil & Gas Operator | Jul 2025 |
| 592 | Superior Production MGMT Inc | Calumet, OK 73014 | Oil & Gas Operator | Mar 2015 |
| 593 | Swadley Roy W & Judith I | Holdenville, OK 74848-0794 | Oil & Gas Operator | Mar 2015 |
| 594 | Synergex Inc | Oklahoma City, OK 73134 | Oil & Gas Operator | Jun 2025 |
| 595 | T & K Oil, Inc | Stephens, AR 71764 | Oil Operator | Jan 2025 |
| 596 | T B K Energy Company | Brenham, TX 77833 | Oil & Gas Operator | Jul 2025 |
| 597 | T T & T Inc | Shawnee, OK 74802-3694 | Oil & Gas Operator | Jan 1994 |
| 598 | Tack Operating LLC | Oklahoma City, OK 73172-1492 | Oil & Gas Operator | Aug 2021 |
| 599 | Tag Petroleum Inc | Stillwater, OK 74076 | Oil & Gas Operator | Jan 2021 |
| 600 | Tcina Inc | Seminole, OK 74868 | Oil & Gas Operator | May 2023 |