| 501 | Robin, Jack, Co. | Corpus Chrsti, TX 78410 | Oil & Gas Operator | Dec 2017 |
| 502 | Robinett Resources Inc. | Longview, TX 75601 | Oil & Gas Operator | Dec 1999 |
| 503 | Robinson Drilling Of Texas | Big Spring, TX 79721 | Oil & Gas Operator | Oct 1996 |
| 504 | Robinson Oil & Gas, Inc. | Chico, TX 76431 | Oil & Gas Operator | Aug 2003 |
| 505 | Robinson Oil Co. | Graham, TX 76450 | Oil & Gas Operator | Oct 2025 |
| 506 | Robinson Operating Company | Abilene, TX 79604 | Oil & Gas Operator | Aug 2012 |
| 507 | Robinson, Irvin | Abilene, TX 79608 | Oil & Gas Operator | May 1999 |
| 508 | Robison, J. H. & Assoc. LTD. | Corpus Chrsti, TX 78413 | Oil & Gas Operator | Apr 1996 |
| 509 | Robuck Petroleum, LLC | Nacogdoches, TX 75965 | Oil & Gas Operator | Oct 2025 |
| 510 | Roc Energy, Inc. | Midland, TX 79710 | Oil & Gas Operator | Feb 2013 |
| 511 | Roc Operating, Inc. | Plano, TX 75093 | Oil & Gas Operator | Oct 2008 |
| 512 | Roca Operating, Inc. | Midland, TX 79702 | Oil & Gas Operator | Oct 2025 |
| 513 | Roca Production, Inc. | Fort Worth, TX 76107 | Oil & Gas Operator | Oct 2025 |
| 514 | Roca Resource Company, Inc. | Midland, TX 79702 | Oil & Gas Operator | Mar 2008 |
| 515 | Rocanville Corporation | Dallas, TX 75225 | Oil & Gas Operator | Dec 2016 |
| 516 | Rocc Oil & Gas, L.P. | Houston, TX 77084 | Oil & Gas Operator | Apr 2024 |
| 517 | Rocc Operating, LLC | Houston, TX 77084 | Oil & Gas Operator | Oct 2025 |
| 518 | Rocinante | Houston, TX 77058 | Oil Operator | Oct 2025 |
| 519 | Rock Bottom Oil, GP, L.L.C. | Nacogdoches, TX 75963 | Oil & Gas Operator | Oct 2025 |
| 520 | Rock Creek Oil Co. | Iowa Park, TX 76367 | Oil Operator | Mar 2008 |
| 521 | Rock Creek Oil, Inc. | Dallas, TX 75225 | Oil & Gas Operator | Nov 2019 |
| 522 | Rock Energy Resources, Inc. | Houston, TX 77056 | Oil & Gas Operator | Oct 2025 |
| 523 | Rock Fish Operating LLC | McKinney, TX 75070 | Oil & Gas Operator | Oct 2025 |
| 524 | Rock Hill Operating | Burkburnett, TX 76354 | Oil & Gas Operator | Oct 2025 |
| 525 | Rock Operating | Abilene, TX 79608 | Oil & Gas Operator | Oct 2025 |
| 526 | Rock Petroleum, LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Aug 2024 |
| 527 | Rock Resources, Inc. | Corpus Chrsti, TX 78414 | Oil & Gas Operator | Oct 2025 |
| 528 | Rock Solid Operating, LLC | Southlake, TX 76092 | Oil Operator | Sep 2021 |
| 529 | Rock Well Petroleum (U.S.), Inc. | Canada, 00100 | Oil & Gas Operator | Sep 2014 |
| 530 | Rockbridge Oil & Gas | Houston, TX 77027 | Oil & Gas Operator | Mar 1990 |
| 531 | Rockbridge Oil And Gas, Inc. | Houston, TX 77227 | Oil & Gas Operator | Nov 1997 |
| 532 | Rockcliff Energy Operating LLC | Houston, TX 77002 | Oil & Gas Operator | Oct 2025 |
| 533 | Rockdale Energy, LLC | Houston, TX 77024 | Oil & Gas Operator | Dec 2020 |
| 534 | Rockdale Resources Corporation | Houston, TX 77024 | Oil Operator | Jul 2016 |
| 535 | Rockefeller Hughes (USA) LLC | Houston, TX 77027 | Oil & Gas Operator | Jul 2015 |
| 536 | Rocker A Operating Company | Post, TX 79356 | Oil & Gas Operator | Aug 2022 |
| 537 | Rocker B Production, L.L.C. | Graham, TX 76450 | Gas Operator | Aug 2025 |
| 538 | Rockford Energy Partners II, LLC | Tulsa, OK 74103 | Oil & Gas Operator | Sep 2007 |
| 539 | Rockford Energy Partners III,LLC | Tulsa, OK 74103 | Oil & Gas Operator | Sep 2012 |
| 540 | Rockford Panhandle, LLC | Tulsa, OK 74105 | Oil & Gas Operator | Sep 2008 |
| 541 | Rockin C Production, L.L.C. | Nocona, TX 76255 | Oil Operator | May 2025 |
| 542 | Rockin' D, LLC | Big Spring, TX 79720 | Oil & Gas Operator | Mar 2024 |
| 543 | Rocking Lazy Little B Ranch Oil | Cedar Creek, TX 78612 | Oil Operator | Apr 2011 |
| 544 | Rocking R Investments, Inc. | San Antonio, TX 78217 | Oil & Gas Operator | Oct 2025 |
| 545 | Rocking, R, Drilling & Prod Co. | Bowie, TX 76230 | Oil & Gas Operator | Oct 2025 |
| 546 | Rockland Oil Company | Addison, TX 75001 | Oil & Gas Operator | Jun 2025 |
| 547 | Rockoil Energy Of Texas, Inc. | Weatherford, TX 76086 | Oil & Gas Operator | Oct 2025 |
| 548 | Rockport Energy Solutions LLC | Austin, TX 78730 | Oil & Gas Operator | Oct 2025 |
| 549 | Rockport Georgetown Holdings,LP | Bellaire, TX 77401 | Oil & Gas Operator | Nov 2007 |
| 550 | Rocksprings Energy Company LLC | Houston, TX 77057 | Oil & Gas Operator | Dec 1997 |
| 551 | Rockstar Production, LLC | Graham, TX 76450 | Oil Operator | Oct 2025 |
| 552 | Rockstar Resources, LLC | Sourlake, TX 77659 | Oil & Gas Operator | Oct 2025 |
| 553 | Rockwall Marketing Corporation | Benbrook, TX 76126 | Oil & Gas Operator | Dec 2007 |
| 554 | Rockwell Energy Corporation | Tulsa, OK 74105 | Oil & Gas Operator | Apr 2014 |
| 555 | Rockwell Energy, LLC | Spring, TX 77386 | Oil & Gas Operator | Sep 2014 |
| 556 | Rockwood Resources Inc | Coleman, TX 76834 | Oil & Gas Operator | Oct 2025 |
| 557 | Rocky Creek Resources, LLC | Houston, TX 77055 | Oil & Gas Operator | Mar 2025 |
| 558 | Rocky Point Oil, Inc. | Wichita Falls, TX 76308 | Oil & Gas Operator | Oct 2025 |
| 559 | Roco Petroleum, Incorporated | Abilene, TX 79605 | Oil & Gas Operator | Oct 2025 |
| 560 | Rocoso Resources, LLC | Albany, TX 76430 | Oil & Gas Operator | Oct 2025 |
| 561 | Rod Oil & Gas LTD. | Houston, TX 77261 | Oil & Gas Operator | Jun 1995 |
| 562 | Rod, Inc. | Coleman, TX 76834 | Oil & Gas Operator | Mar 2008 |
| 563 | Rodan, Inc. | Wink, TX 79789 | Oil & Gas Operator | Oct 2025 |
| 564 | Rodel Oil & Gas Company | Houston, TX 77218 | Oil & Gas Operator | Oct 2025 |
| 565 | Roden Oil Company | Midland, TX 79702 | Oil & Gas Operator | Feb 2008 |
| 566 | Rodenberg, Laura Oil Co. | Luling, TX 78648 | Oil & Gas Operator | Oct 2025 |
| 567 | Rodeo Resources, L.L.C. | Houston, TX 77079 | Oil & Gas Operator | Dec 2024 |
| 568 | Rodessa Management, Inc. | Longview, TX 75606 | Oil & Gas Operator | May 1995 |
| 569 | Rodessa Operating Company | Corpus Chrsti, TX 78426 | Oil & Gas Operator | Oct 2025 |
| 570 | Rodgers, William L. | Fort Worth, TX 76147 | Oil & Gas Operator | Jan 1995 |
| 571 | Rodman Petroleum Corp. | Odessa, TX 79768 | Oil & Gas Operator | Jul 2023 |
| 572 | Roemer Oil Company | Denver, CO 80202 | Oil & Gas Operator | Nov 1998 |
| 573 | Roemer, David E. | Somerset, TX 78069 | Oil Operator | Oct 2025 |
| 574 | Roff Operating Company LLC | Houston, TX 77002 | Oil & Gas Operator | Oct 2025 |
| 575 | Rog Enterprises, Inc. | Lake Dallas, TX 75065 | Oil Operator | May 2014 |
| 576 | Rog Enterprises, LLC | Burkburnett, TX 76354 | Oil Operator | Oct 2025 |
| 577 | Rogers Drilling Co. | Olney, TX 76374 | Oil & Gas Operator | Oct 2025 |
| 578 | Rogers Oilfield Op, Corp. | Granbury, TX 76048 | Oil & Gas Operator | Jul 2019 |
| 579 | Rogers, M. L. | Midland, TX 79701 | Oil & Gas Operator | Sep 2014 |
| 580 | Rogers, Mike Drilling Co., Inc. | Magnolia, AR 71754 | Oil & Gas Operator | Sep 2002 |
| 581 | Rogers, S. K. Oil, Inc. | Lubbock, TX 79424 | Oil & Gas Operator | Oct 2025 |
| 582 | Rohmer Brother'S | Muenster, TX 76252 | Oil & Gas Operator | May 2014 |
| 583 | Rohmer Resources LP | Muenster, TX 76252 | Oil Operator | Oct 2025 |
| 584 | Rohmer, A. J. | Muenster, TX 76252 | Oil & Gas Operator | Apr 1997 |
| 585 | Rohmer, Tony S. | Muenster, TX 76252 | Oil & Gas Operator | Sep 2015 |
| 586 | Rohmer, William J. | Muenster, TX 76252 | Oil & Gas Operator | Dec 2011 |
| 587 | Roil Mineral & Land Co. | Dallas, TX 75379 | Oil & Gas Operator | Oct 2025 |
| 588 | Roil Production Company | Houston, TX 77056 | Gas Operator | Sep 2005 |
| 589 | Rojo Burro Petroleo & Gas | Kilgore, TX 75662 | Oil & Gas Operator | Aug 2007 |
| 590 | Rojo Oil Company | McLean, TX 79057 | Oil & Gas Operator | Oct 2025 |
| 591 | Roland Carlson LLC | Austin, TX 78705 | Gas Operator | Oct 2025 |
| 592 | Roland Oil Company | Charlotte, TX 78011 | Oil & Gas Operator | Oct 2025 |
| 593 | Rollert Co., Inc., The | Luling, TX 78648 | Oil & Gas Operator | Nov 2000 |
| 594 | Rollo Resources, LLC | Granbury, TX 76049 | Gas Operator | Oct 2025 |
| 595 | Roma Oil And Gas, Inc. | San Antonio, TX 78209 | Oil & Gas Operator | Oct 2025 |
| 596 | Romac Oil Company, Inc. | Throckmorton, TX 76483 | Oil & Gas Operator | Oct 2025 |
| 597 | Romack Production Company | Granville, OH 43023 | Oil Operator | Mar 2018 |
| 598 | Romco | Muenster, TX 76252 | Oil & Gas Operator | Mar 2015 |
| 599 | Romine Oil & Gas, LLC | Midland, TX 79710 | Oil & Gas Operator | Oct 2025 |
| 600 | Romines & Warner | Pampa, TX 79065 | Oil & Gas Operator | Jan 2002 |