| 501 | RCS Oil | | Oil Operator | Sep 2025 |
| 502 | RCV Investments, LLC | | Oil & Gas Operator | Jan 2025 |
| 503 | RCW Oil Company | Forsan, TX 79733 | Oil & Gas Operator | Mar 2019 |
| 504 | RCW Oil, LLC | Forsan, TX 79733 | Oil & Gas Operator | Feb 2026 |
| 505 | Rcy Mineral Group, Inc. | El Campo, TX 77437 | Oil Operator | Jul 2010 |
| 506 | RDG Oil & Gas LLC | Post Falls, ID 82854 | Oil & Gas Operator | Mar 2017 |
| 507 | RDH Enterprises Inc | El Reno, OK 73036 | Oil & Gas Operator | May 2015 |
| 508 | RDT Properties, Inc. | Tulsa, OK 74136 | Oil & Gas Operator | Oct 2012 |
| 509 | Re Fox & Assoc Inc | Pittsburgh, PA 15243-0130 | Gas Operator | Dec 1999 |
| 510 | Re Gas Dev LLC | State College, PA 16801-7085 | Oil & Gas Operator | Sep 2018 |
| 511 | Re-Op Corp. | Houston, TX 77274 | Oil & Gas Operator | Feb 2026 |
| 512 | Reabold California LLC | | Oil & Gas Operator | Nov 2025 |
| 513 | Reach Group-Reac | | Oil & Gas Operator | Apr 1995 |
| 514 | Reach Oil | Brownwood, TX 76801 | Oil & Gas Operator | Feb 2026 |
| 515 | Reach Oil And Gas Company Inc | Oklahoma City, OK 73118-1100 | Oil & Gas Operator | Nov 2025 |
| 516 | Reach Petroleum | | Oil & Gas Operator | Jan 1994 |
| 517 | Reach Petroleum Corporation | Wichita, KS 67218 | Oil & Gas Operator | Dec 2009 |
| 518 | Read & Stevens, Inc. | Denver, CO 80202 | Oil & Gas Operator | Jul 2023 |
| 519 | Reading & Bates Petroleum | | Oil & Gas Operator | Apr 1989 |
| 520 | Reading & Bates Petroleum Co | Tulsa, OK 74136 | Oil & Gas Operator | Aug 2009 |
| 521 | Ready Oil & Gas | Artesia, NM 882110381 | Oil & Gas Operator | Dec 2007 |
| 522 | Reagan Exploration Company Inc | | Oil & Gas Operator | Nov 1998 |
| 523 | Reagan Production Inc | Terral, OK 73569 | Oil Operator | Nov 2025 |
| 524 | Reagle Production Co. | Snyder, TX 79549 | Oil & Gas Operator | Apr 2004 |
| 525 | Real Production Management LLC | Woodward, OK 73801 | Oil Operator | Oct 2025 |
| 526 | Realco Oil & Gas, Inc. | | Oil & Gas Operator | Sep 2007 |
| 527 | Realitos Energy Corporation | | Oil & Gas Operator | Mar 1991 |
| 528 | Reames Jr Keith E | Duncan, OK 73534-0246 | Oil & Gas Operator | Jul 1999 |
| 529 | Reata Petroleum LLC | Independence, KS 67301 | Oil & Gas Operator | Sep 2025 |
| 530 | Reata Resources | Kermit, TX 79745 | Oil & Gas Operator | Sep 2007 |
| 531 | Reatta Energy, Inc. | Midland, TX 79702 | Oil & Gas Operator | Feb 2026 |
| 532 | Reaves Operator | Stephens, AR 71764 | Oil Operator | Jan 2025 |
| 533 | Reavis, Tommy | San Antonio, TX 78227 | Gas Operator | Feb 2026 |
| 534 | Reb Petroleum Company | Sugar Land, TX 77478 | Oil & Gas Operator | Feb 2026 |
| 535 | Rebco Oil, Inc. | Desdemona, TX 76445 | Oil Operator | Feb 2026 |
| 536 | Rebel Drilling Co. Inc. | | Oil & Gas Operator | Oct 1995 |
| 537 | Rebel Drilling Company, L. P. | | Oil & Gas Operator | Sep 2004 |
| 538 | Rebel Energy, LTD. | Weatherford, TX 76087 | Gas Operator | Nov 2018 |
| 539 | Rebel Enterprises, Inc. | | Oil Operator | Dec 1991 |
| 540 | Rebel Land And Exploration Inc | | Oil & Gas Operator | Aug 1989 |
| 541 | Rebel Oil Company | Keaton, KY 41226 | Oil & Gas Operator | Jan 2025 |
| 542 | Rebel Oil LLC | | Oil Operator | Sep 2025 |
| 543 | Rebel Oil Of North Louisiana, LLC | | Oil & Gas Operator | Dec 2007 |
| 544 | Rebel Production Company | Kilgore, TX 75663 | Oil Operator | Feb 2026 |
| 545 | Rebel Resources LBC LLC | Sunray, TX 79086 | Gas Operator | Feb 2026 |
| 546 | Rebellion Energy LLC | Tulsa, OK 74135-6241 | Oil & Gas Operator | Jun 2022 |
| 547 | Reber Matthew A Mrs | Grove, OK 74344-3605 | Oil & Gas Operator | Jul 2004 |
| 548 | Rebilas, Mark | East Aurora, NY 14052 | Gas Operator | Dec 2024 |
| 549 | Rec Well Service, Inc. | Pleasanton, TX 78064 | Oil & Gas Operator | Jul 2008 |
| 550 | Rec, LLC | Pleasanton, TX 78064 | Oil & Gas Operator | Feb 2026 |
| 551 | Reclusive Energy LLC | Gifford, PA 16732 | Oil & Gas Operator | Dec 2020 |
| 552 | Recoil Resources Operating, Inc. | Houston, TX 77046 | Oil & Gas Operator | Mar 2024 |
| 553 | Recon Oil Co. | Emory, TX 75440 | Oil & Gas Operator | Feb 2026 |
| 554 | Recon Operating Inc | | Oil & Gas Operator | Jun 1991 |
| 555 | Recovery Energy, Inc | | Oil Operator | Dec 2012 |
| 556 | Recovery Operating LP | San Angelo, TX 76904 | Oil & Gas Operator | Feb 2026 |
| 557 | Recovery Resourc | | Oil Operator | Dec 1986 |
| 558 | Red Arrow Energy, LLC | Houston, TX 77027 | Oil & Gas Operator | Jul 2016 |
| 559 | Red Bear Drillin | | Oil & Gas Operator | Sep 1992 |
| 560 | Red Bird Producing Co | Wooster, OH 44691 | Oil & Gas Operator | Dec 2024 |
| 561 | Red Bluff Resources Operating LLC | Oklahoma City, OK 73112-5468 | Oil & Gas Operator | Nov 2025 |
| 562 | Red Buck Oil Company | Copan, OK 74022-0215 | Oil Operator | Nov 2009 |
| 563 | Red Byrd Oil, LLC | Crystal City, TX 78839 | Oil Operator | Feb 2026 |
| 564 | Red Cedar Oil, LLC | Medicine Lodge, KS 67104 | Oil & Gas Operator | Jul 2025 |
| 565 | Red Chalk Resources LLC | Houston, TX 77218 | Oil Operator | Feb 2026 |
| 566 | Red Cloud Exploration Operating LLC | Calabasas, CA 91302 | Oil Operator | Feb 2016 |
| 567 | Red Dirt Environmental Services LLC | Checotah, OK 74426 | Oil & Gas Operator | Nov 2025 |
| 568 | Red Dove Oil & Gas, LLC | Mineral Wells, TX 76067 | Gas Operator | Feb 2026 |
| 569 | Red Eagle Oil Company | Oklahoma City, OK 73154 | Oil & Gas Operator | Mar 2005 |
| 570 | Red Earth Oil & Gas, Inc. | Oklahoma City, OK 73159 | Oil & Gas Operator | Oct 2021 |
| 571 | Red Fork (USA) Investments Inc | Midland, TX 79710-0272 | Oil & Gas Operator | May 2019 |
| 572 | Red Fork Oil Co | Lakewood, CO 80215 | Oil & Gas Operator | Aug 1993 |
| 573 | Red Fork Oil Production Inc | Mannford, OK 74044-0492 | Oil & Gas Operator | Feb 2017 |
| 574 | Red Fork Production, LLC | San Antonio, TX 78217 | Oil & Gas Operator | Nov 2025 |
| 575 | Red Fork Valley Oil & Gas Co | Cushing, OK 74023 | Oil Operator | Dec 2014 |
| 576 | Red Gap Oil & Gas LLC | Cisco, TX 76437 | Oil & Gas Operator | Feb 2026 |
| 577 | Red Gas Company | Weston, WV 26452-0000 | Oil & Gas Operator | Dec 2021 |
| 578 | Red Hawk Disposal LLC | Oklahoma City, OK 73172 | Oil Operator | Jun 2023 |
| 579 | Red Hawk Resources Inc | Edmond, OK 73003-3207 | Oil & Gas Operator | Dec 2025 |
| 580 | Red Hills Energy, LLC | Medicine Lodge, KS 67104 | Oil & Gas Operator | Sep 2025 |
| 581 | Red Hills Resources, Inc. | Englewood, KS 67840 | Oil & Gas Operator | Sep 2025 |
| 582 | Red Horse Petroleum | Dallas, TX 75240 | Oil & Gas Operator | Feb 2026 |
| 583 | Red Jack Oil LLC | | Oil Operator | May 2013 |
| 584 | Red Jacket Energy LLC | Roulette, PA 16746-1408 | Oil & Gas Operator | Dec 2024 |
| 585 | Red Line Company, LTD. | Pampa, TX 79066 | Oil & Gas Operator | Feb 2026 |
| 586 | Red Man Oil, Co. | Albany, TX 76430 | Oil & Gas Operator | Feb 2026 |
| 587 | Red Maple Acres, LLC | Scipio Center, NY 13147 | Gas Operator | Dec 2024 |
| 588 | Red Mesa Holdings/O&G LLC | | Oil & Gas Operator | Nov 2014 |
| 589 | Red Mountain Energy LLC | | Oil & Gas Operator | Sep 2017 |
| 590 | Red Mountain Oil LLC | Golden, CO 80402 | Oil Operator | Nov 1997 |
| 591 | Red Mountain Operating LLC | Oklahoma City, OK 73118-1253 | Oil & Gas Operator | Apr 2024 |
| 592 | Red Mountain Resources LLC | | Oil & Gas Operator | Sep 2023 |
| 593 | Red Oak Energy Co | San Angelo, TX 76906 | Oil & Gas Operator | Feb 2026 |
| 594 | Red Oak Energy LLC | Clarksburg, PA 15725-8824 | Oil & Gas Operator | Dec 2025 |
| 595 | Red Oak Energy, Inc. | Wichita, KS 67207 | Oil & Gas Operator | Sep 2025 |
| 596 | Red Oak Gas Operating Company LP | Houston, TX 77056 | Oil & Gas Operator | Dec 2017 |
| 597 | Red Oak Oil Company, LLC | Spring, TX 77379 | Oil Operator | Feb 2026 |
| 598 | Red Oak Operating, LLC | Magnolia, AR 71753 | Oil & Gas Operator | Jan 2025 |
| 599 | Red Ox Resources LLC | Dumas, TX 79029 | Gas Operator | Dec 2025 |
| 600 | Red Plains Oil & Gas LLC | Kingfisher, OK 73750 | Oil & Gas Operator | Oct 2017 |