| 601 | Ress Production Co. | Farmington, NM 87499 | Oil & Gas Operator | Oct 2025 |
| 602 | Richardson Operating Company | Denver, CO 80237 | Oil & Gas Operator | Jul 2025 |
| 603 | Richman Petroleum Corp. | Grapevine, TX 76051 | Oil & Gas Operator | Jul 2006 |
| 604 | Richter Operating Company | San Antonio, TX 78217 | Oil & Gas Operator | Dec 2007 |
| 605 | Ricks Exploration, Inc. | Oklahoma City, OK 73154 | Oil & Gas Operator | Mar 2008 |
| 606 | Riddle Engineering Corp. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Jul 2011 |
| 607 | Rife Oil Properties Inc | Fort Worth, TX 76107 | Oil & Gas Operator | Oct 2025 |
| 608 | Riley Exploration Opg Co, LLC | La Grange, TX 78945 | Oil & Gas Operator | Oct 2025 |
| 609 | Rincon Petroleum Corporation | Corpus Chrsti, TX 78427 | Oil & Gas Operator | Oct 2025 |
| 610 | Rio Bravo Oil Company | The Woodlands, TX 77381 | Oil & Gas Operator | Feb 2002 |
| 611 | Rio Exploration Company | San Antonio, TX 78209 | Gas Operator | Dec 2005 |
| 612 | Rio-Tex, Inc. | San Antonio, TX 78217 | Oil & Gas Operator | Oct 2025 |
| 613 | Rise Petroleum Investments LLC | Tomball, TX 77377 | Oil & Gas Operator | Oct 2025 |
| 614 | Riseden Services, Inc. | Houston, TX 77256 | Oil & Gas Operator | Sep 1997 |
| 615 | RMR Operating, LLC | Plano, TX 75024 | Oil & Gas Operator | Oct 2025 |
| 616 | Robison, J. H. & Assoc. LTD. | Corpus Chrsti, TX 78413 | Oil & Gas Operator | Apr 1996 |
| 617 | Roc Operating, Inc. | Plano, TX 75093 | Oil & Gas Operator | Oct 2008 |
| 618 | Rock Resources, Inc. | Corpus Chrsti, TX 78414 | Oil & Gas Operator | Oct 2025 |
| 619 | Rockdale Energy, LLC | Houston, TX 77024 | Oil & Gas Operator | Dec 2020 |
| 620 | Rocksprings Energy Company LLC | Houston, TX 77057 | Oil & Gas Operator | Dec 1997 |
| 621 | Rockwell Energy, LLC | Spring, TX 77386 | Oil & Gas Operator | Sep 2014 |
| 622 | Rodel Oil & Gas Company | Houston, TX 77218 | Oil & Gas Operator | Oct 2025 |
| 623 | Rodessa Operating Company | Corpus Chrsti, TX 78426 | Oil & Gas Operator | Oct 2025 |
| 624 | Roma Oil And Gas, Inc. | San Antonio, TX 78209 | Oil & Gas Operator | Oct 2025 |
| 625 | Ronde Operating, LLC | Houston, TX 77006 | Oil & Gas Operator | Mar 2021 |
| 626 | Rosenthal, Stanley H. | Bay City, TX 77404 | Oil & Gas Operator | Dec 2020 |
| 627 | Rosetta Resources Operating LP | San Antonio, TX 78216 | Oil & Gas Operator | Oct 2025 |
| 628 | Rowden Oil & Gas, Inc. | San Antonio, TX 78209 | Oil & Gas Operator | Jun 2023 |
| 629 | Royal Oil & Gas Corp. | Indiana, PA 15701 | Oil & Gas Operator | Apr 2014 |
| 630 | Royal Production Company, Inc. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Oct 2025 |
| 631 | Royko Oil Company | Horseshoe Bay, TX 78657 | Oil & Gas Operator | Oct 2025 |
| 632 | Rto Operating, LLC | San Antonio, TX 78212 | Oil Operator | Feb 2016 |
| 633 | Rystin Oil & Gas | Sugar Land, TX 77487 | Oil & Gas Operator | Oct 2025 |
| 634 | S M K Energy Corporation | Corpus Chrsti, TX 78475 | Oil & Gas Operator | Oct 2025 |
| 635 | Saba Energy Of Texas Inc | Houston, TX 77042 | Oil & Gas Operator | Jul 2007 |
| 636 | Sabalo Exploration Operating,LLC | Corpus Chrsti, TX 78404 | Oil & Gas Operator | Jan 2021 |
| 637 | Safari Production Company, Inc. | McAllen, TX 78501 | Oil & Gas Operator | Oct 2025 |
| 638 | Sage Energy Company | San Antonio, TX 78215 | Oil & Gas Operator | Oct 2025 |
| 639 | Samedan Oil Corporation | Houston, TX 77067 | Oil & Gas Operator | Dec 2019 |
| 640 | Samson Hydrocarbons Company | Tulsa, OK 74103 | Oil & Gas Operator | Nov 2016 |
| 641 | Samson Lone Star LP | Tulsa, OK 74103 | Oil & Gas Operator | Jun 2007 |
| 642 | Samson Resources Company | Tulsa, OK 74103 | Oil & Gas Operator | Jun 2025 |
| 643 | San Isidro Development Co, L. C. | Sandia, TX 78383 | Oil & Gas Operator | Oct 2025 |
| 644 | San Patricio Corporation | Dinero, TX 78350 | Oil & Gas Operator | Sep 2003 |
| 645 | Sanchez Oil & Gas Corporation | Houston, TX 77056 | Oil & Gas Operator | Oct 2025 |
| 646 | Sanchez-O'Brien Oil & Gas Corp | Houston, TX 77057 | Oil & Gas Operator | May 1998 |
| 647 | Sandalwood Exploration, L.P. | Houston, TX 77056 | Oil & Gas Operator | Oct 2025 |
| 648 | Santa Fe Energy Oper. Part., LP | Houston, TX 77057 | Oil & Gas Operator | Dec 1994 |
| 649 | Santa Rosa Operating, LLC | Corpus Chrsti, TX 78411 | Oil & Gas Operator | Oct 2025 |
| 650 | Santos USA Corp. | Houston, TX 77042 | Oil & Gas Operator | Dec 2008 |
| 651 | Saratoga Resources, Inc. | Houston, TX 77077 | Oil & Gas Operator | Jul 1994 |
| 652 | Sarrita Oil Co., Inc. | Floresville, TX 78114 | Oil & Gas Operator | Jul 2002 |
| 653 | Satex Energy, Inc. | San Antonio, TX 78216 | Oil & Gas Operator | Aug 2003 |
| 654 | Savage Exploration, Inc. | San Marcos, TX 78666 | Oil & Gas Operator | Oct 2025 |
| 655 | Saxet Energy, LTD. | Houston, TX 77057 | Oil & Gas Operator | Mar 2004 |
| 656 | Saxet Petroleum, Inc. | Houston, TX 77057 | Oil & Gas Operator | Oct 2025 |
| 657 | Saxum Oil & Gas, LLC | Beeville, TX 78104 | Oil & Gas Operator | Oct 2025 |
| 658 | Schlachter Operating Corporation | Dallas, TX 75225 | Oil & Gas Operator | Oct 2025 |
| 659 | Schlachter, David A. | Dallas, TX 75225 | Oil & Gas Operator | Apr 2015 |
| 660 | Schlachter, David A., Estate Of | Dallas, TX 75225 | Oil & Gas Operator | Jan 2000 |
| 661 | Scorpion Operating, Inc. | Benavides, TX 78341 | Oil Operator | Oct 2025 |
| 662 | Seagull Energy E & P Inc | Houston, TX 77002 | Oil & Gas Operator | Jan 2015 |
| 663 | Seagull Operating Co., Inc. | Shreveport, LA 71101 | Oil & Gas Operator | Jan 2025 |
| 664 | Sedco Resources Inc | Kerrville, TX 78029 | Oil & Gas Operator | Oct 2025 |
| 665 | Sedona Oil & Gas Corporation | Austin, TX 78746 | Oil & Gas Operator | Oct 2025 |
| 666 | Sendero Energy Inc. | Dallas, TX 75205 | Oil & Gas Operator | Oct 2025 |
| 667 | Sequoia Management, LLC | Houston, TX 77060 | Oil & Gas Operator | Nov 2009 |
| 668 | Serna Inc. | Austin, TX 78733 | Oil Operator | Oct 2025 |
| 669 | Seventy Oil Co. | Freer, TX 78357 | Oil & Gas Operator | Mar 2002 |
| 670 | Shell Western E&P | Houston, TX 77001 | Oil & Gas Operator | Oct 2025 |
| 671 | Shell Western E&P Inc. | Houston, TX 77001 | Oil & Gas Operator | May 2011 |
| 672 | Sheridan Energy,Inc. | Houston, TX 77002 | Oil & Gas Operator | Feb 2000 |
| 673 | Shidler, Mark L., Inc. | Houston, TX 77055 | Oil & Gas Operator | Oct 2025 |
| 674 | Silver Creek Oil & Gas, LLC | Flower Mound, TX 75022 | Oil & Gas Operator | Oct 2025 |
| 675 | Silver Creek Resources, LLC | Irving, TX 75038 | Oil & Gas Operator | Apr 2017 |
| 676 | Simray GP, LLC | Richardson, TX 75080 | Oil & Gas Operator | Dec 2015 |
| 677 | Slate Holdings, Inc. | Mineral Wells, TX 76068 | Oil & Gas Operator | Oct 2025 |
| 678 | Slaughter J M Oil Company | Fort Worth, TX 76116 | Oil & Gas Operator | Jan 2001 |
| 679 | Smith Operating And MGMT Co. | Shreveport, LA 71161 | Oil & Gas Operator | Jun 2023 |
| 680 | Smith Production Inc. | The Woodlands, TX 77381 | Oil & Gas Operator | Oct 2025 |
| 681 | Smith, R. E. Interests, Inc. | Houston, TX 77027 | Oil & Gas Operator | Mar 1998 |
| 682 | Sonat Exploration Co. - Houston | Houston, TX 77251 | Oil & Gas Operator | Dec 1999 |
| 683 | South Texas Operating Company | San Antonio, TX 78217 | Oil & Gas Operator | Oct 2025 |
| 684 | Southern Bay Operating, L.L.C. | Houston, TX 77002 | Oil & Gas Operator | Jun 2013 |
| 685 | Southern Resource Company | Corpus Chrsti, TX 78404 | Oil & Gas Operator | Mar 2022 |
| 686 | Southwest Gathering Company | Alice, TX 78332 | Oil & Gas Operator | Oct 2025 |
| 687 | Southwest Land & Minerals, Inc. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Aug 2003 |
| 688 | Southwest Oil & Land, Inc. | Corpus Chrsti, TX 78460 | Oil & Gas Operator | Dec 1999 |
| 689 | Southwest Royalties Inc | Midland, TX 79710 | Oil & Gas Operator | Oct 2025 |
| 690 | Southwestern Energy Prod Co | Houston, TX 77032 | Oil & Gas Operator | Jun 2015 |
| 691 | Sparks, Sidney A., Trustee | Alice, TX 78332 | Oil & Gas Operator | Jun 1996 |
| 692 | Speed, F. Michael, Trustee | Corpus Chrsti, TX 78473 | Oil & Gas Operator | Aug 1998 |
| 693 | Spiller Operating Co., Inc. | Round Rock, TX 78665 | Oil & Gas Operator | May 2015 |
| 694 | Star Oil & Gas | Ben Bolt, TX 78342 | Oil & Gas Operator | Oct 2025 |
| 695 | Stephens Production Company | The Woodlands, TX 77381 | Oil & Gas Operator | Jul 2025 |
| 696 | Sterling Engine Service, Inc. | Alice, TX 78333 | Oil & Gas Operator | Oct 2025 |
| 697 | Stinger Oil & Gas Inc. | Sherman Oaks, CA 91403 | Oil & Gas Operator | Oct 2013 |
| 698 | Stonegate Operators, Inc. | Addison, TX 75001 | Oil Operator | Oct 2025 |
| 699 | Sue-Ann Operating, L.C. | Victoria, TX 77903 | Oil & Gas Operator | Oct 2025 |
| 700 | Sue-Ann Production Company | Victoria, TX 77903 | Oil & Gas Operator | Mar 2008 |