| 501 | Simpson Bros. Oil Co.-Odessa | Odessa, TX 79760 | Oil & Gas Operator | Jan 2001 |
| 502 | Simpson Oil & Land Co. | Fort Worth, TX 76102 | Oil & Gas Operator | Apr 2024 |
| 503 | Simpson Oil Company | Odessa, TX 79760 | Oil & Gas Operator | Oct 2004 |
| 504 | Simpson Operating Services, LP | Ballinger, TX 76821 | Oil & Gas Operator | Apr 2024 |
| 505 | Simpson, A. E. | Electra, TX 76360 | Oil & Gas Operator | Dec 2006 |
| 506 | Simray GP, LLC | Richardson, TX 75080 | Oil & Gas Operator | Dec 2015 |
| 507 | Simray Oil & Gas, Inc. | Richardson, TX 75080 | Oil & Gas Operator | Sep 2003 |
| 508 | Simray Operating Corp. | Richardson, TX 75080 | Oil & Gas Operator | Mar 2009 |
| 509 | Sims, John S. | Lawn, TX 79530 | Oil & Gas Operator | Aug 2003 |
| 510 | Sinclair Development, LLC | Kilgore, TX 75663 | Oil & Gas Operator | Apr 2024 |
| 511 | Sinclair Energy Corporation | Fort Worth, TX 76177 | Oil & Gas Operator | Apr 2024 |
| 512 | Sinclair Exploration Company | Abilene, TX 79604 | Oil & Gas Operator | Nov 1998 |
| 513 | Sinclair Oil & Gas Company | Salt Lake Cty, UT 84130 | Oil & Gas Operator | Apr 2024 |
| 514 | Sinclair Oil Corporation | Salt Lake Cty, UT 84130 | Oil & Gas Operator | Aug 2006 |
| 515 | Single Barrel Oil And Gas LLC | Granbury, TX 76048 | Oil & Gas Operator | Apr 2024 |
| 516 | Singleton Investments, Inc. | Breckenridge, TX 76424 | Oil & Gas Operator | Oct 2012 |
| 517 | Sink Hole, Inc. | Levelland, TX 79336 | Oil & Gas Operator | Dec 2000 |
| 518 | Sinow, G. S. | Pampa, TX 79066 | Oil & Gas Operator | Oct 1995 |
| 519 | Sip'S Oil & Gas Inc | Yukon, OK 73099 | Oil & Gas Operator | Apr 2024 |
| 520 | Sirena Holdings LLC Series 1 | Moran, TX 76464 | Oil & Gas Operator | Apr 2024 |
| 521 | Siroco Operating Co., Inc. | Kilgore, TX 75663 | Oil & Gas Operator | Apr 2010 |
| 522 | Sissom Oil | Holliday, TX 76366 | Oil & Gas Operator | Mar 2008 |
| 523 | Sissom Oil Field Services, LLC | Wichita Falls, TX 76308 | Oil Operator | Apr 2024 |
| 524 | Sisters Operating Company | Victoria, TX 77904 | Oil & Gas Operator | Nov 2010 |
| 525 | Sitton, Ronnie Incorporated | Graford, TX 76449 | Oil & Gas Operator | Feb 2020 |
| 526 | Situs Oil & Gas, LLC | Corpus Chrsti, TX 78414 | Oil Operator | Apr 2024 |
| 527 | Six Oil Producers | Abilene, TX 79601 | Oil & Gas Operator | Sep 2002 |
| 528 | Six-S Properties, Inc. | Austin, TX 78767 | Oil & Gas Operator | Apr 2024 |
| 529 | Sixess Energy, LLC | Midland, TX 79702 | Oil & Gas Operator | Apr 2024 |
| 530 | Sizemore, James | Hardin, TX 77561 | Oil & Gas Operator | Jun 2003 |
| 531 | Skaar, K. M. Oil & Gas Co. | Midland, TX 79710 | Oil & Gas Operator | Apr 2024 |
| 532 | Skewes Operating Company | Bluefield, VA 24605 | Oil & Gas Operator | Apr 2024 |
| 533 | Skidmore Energy,Inc. | Salado, TX 76571 | Oil & Gas Operator | Jun 1999 |
| 534 | Skidmore Exploration, Inc. | Dallas, TX 75219 | Oil & Gas Operator | Jul 1997 |
| 535 | Skidmore, James E. | Nocona, TX 76255 | Oil & Gas Operator | Nov 2008 |
| 536 | Skinner Cattle, Inc. | Nocona, TX 76255 | Oil Operator | Apr 2024 |
| 537 | Skinner Energy Management, Inc. | Shreveport, LA 71135 | Oil & Gas Operator | Jan 2011 |
| 538 | Skinner, Robert V. | Spearman, TX 79081 | Oil & Gas Operator | Aug 2008 |
| 539 | Skinner, W. E. | Wichita Falls, TX 76301 | Oil & Gas Operator | Apr 2024 |
| 540 | Skinnergy Co. | Spearman, TX 79081 | Oil & Gas Operator | Apr 2024 |
| 541 | Sklar & Phillips Oil Co. | Shreveport, LA 71101 | Oil & Gas Operator | Dec 2000 |
| 542 | Sklar Exploration Company LLC | Shreveport, LA 71101 | Oil & Gas Operator | Apr 2024 |
| 543 | Sklar-Tex L.L.C. | Shreveport, LA 71101 | Oil & Gas Operator | Apr 2001 |
| 544 | Skrivanos Engineering, Inc. | Shreveport, LA 71164 | Oil & Gas Operator | Dec 2011 |
| 545 | SKS Oil | Olney, TX 76374 | Oil & Gas Operator | Apr 2024 |
| 546 | Sky Development Corporation | Graham, TX 76450 | Oil & Gas Operator | Mar 2008 |
| 547 | Sky Resources, Inc. | Graham, TX 76450 | Oil & Gas Operator | Apr 2024 |
| 548 | Skybridge Energy LLC | Jacksboro, TX 76458 | Oil & Gas Operator | Apr 2024 |
| 549 | Skycap Energy, LLC | Oklahoma City, OK 73118 | Oil & Gas Operator | Jan 2024 |
| 550 | Skytop Oil & Gas | Giddings, TX 78942 | Oil & Gas Operator | Apr 2024 |
| 551 | Skyway Energy LLC | Leesburg, OH 34748 | Oil & Gas Operator | Dec 2020 |
| 552 | Slack Oil & Gas | Refugio, TX 78377 | Oil & Gas Operator | Dec 2012 |
| 553 | Slack, R. C. | Pecos, TX 79772 | Oil & Gas Operator | Jul 2000 |
| 554 | Slagel, H. P. Prod. Co. | Snyder, TX 79550 | Oil & Gas Operator | Dec 2006 |
| 555 | Slant Operating, LLC | Lafayette, LA 70503 | Oil & Gas Operator | Apr 2024 |
| 556 | Slape Oil Company, Inc. | Houston, TX 77064 | Oil & Gas Operator | Jun 2011 |
| 557 | Slate Holdings, Inc. | Mineral Wells, TX 76068 | Oil & Gas Operator | Apr 2024 |
| 558 | Slatex Well Service, Inc. | Batson, TX 77519 | Oil Operator | Apr 2024 |
| 559 | Slaughter J M Oil Company | Fort Worth, TX 76116 | Oil & Gas Operator | Jan 2001 |
| 560 | Slawson Exploration Company Inc | Oklahoma City, OK 73102 | Oil & Gas Operator | Apr 2024 |
| 561 | Sledge Bros. Oil Co. | Midland, TX 79702 | Oil & Gas Operator | Mar 2016 |
| 562 | Sledge, H. G., Inc. | Midland, TX 79701 | Oil & Gas Operator | Dec 2016 |
| 563 | Slick Inc. | MC Gregor, TX 76657 | Oil Operator | Apr 2024 |
| 564 | Slick Production, LLC | Muenster, TX 76252 | Oil & Gas Operator | Apr 2024 |
| 565 | Slingshot Oil & Gas | Houston, TX 77019 | Oil Operator | Apr 2024 |
| 566 | Sloan Oil Corporation | Humble, TX 77347 | Oil & Gas Operator | Mar 2015 |
| 567 | Sloan Petroleum Inc. | Midland, TX 79710 | Oil & Gas Operator | Apr 2024 |
| 568 | SLT Dakota Operating, Inc. | Yukon, OK 73099 | Oil & Gas Operator | Apr 2024 |
| 569 | SM Energy Company | Midland, TX 79707 | Oil & Gas Operator | Apr 2024 |
| 570 | SM Operating Company LLC | Houston, TX 77056 | Oil & Gas Operator | Apr 2024 |
| 571 | Smackover Shell LTD. Partnership | Houston, TX 77001 | Gas Operator | Apr 2000 |
| 572 | Smail, James R. | Big Prairie, OH 44611 | Oil & Gas Operator | Dec 1998 |
| 573 | Smal Energy Corp | Tyler, TX 75710 | Oil & Gas Operator | Oct 1995 |
| 574 | Small, R.P. Corp. | Tulsa, OK 74103 | Oil Operator | Apr 2024 |
| 575 | Smalley, Bill | Albany, TX 76430 | Oil & Gas Operator | Jul 2001 |
| 576 | SMC Oil & Gas, Inc. | Midland, TX 79710 | Oil & Gas Operator | Apr 2024 |
| 577 | Smith & Marrs Inc. | Lubbock, TX 79424 | Oil & Gas Operator | Apr 2021 |
| 578 | Smith & Spragins | Wichita Falls, TX 76301 | Oil & Gas Operator | Jul 1995 |
| 579 | Smith Brothers Oil & Gas, Inc. | Midland, TX 79702 | Oil & Gas Operator | Apr 2024 |
| 580 | Smith Energy 1986a Partnership | Alvin, TX 77511 | Oil & Gas Operator | Feb 2010 |
| 581 | Smith Energy Operating Company | Lubbock, TX 79423 | Oil & Gas Operator | Apr 2024 |
| 582 | Smith Family LTD Partnership | Wichita Falls, TX 76308 | Oil & Gas Operator | Feb 2004 |
| 583 | Smith Oil Company | Smackover, AR 71762 | Oil Operator | Mar 2024 |
| 584 | Smith Operating & Management Co. | Shreveport, LA 71161 | Oil & Gas Operator | Dec 2022 |
| 585 | Smith Operating And MGMT Co. | Shreveport, LA 71161 | Oil & Gas Operator | Jun 2023 |
| 586 | Smith Petroleum Company | Spring, TX 77389 | Oil & Gas Operator | Apr 2024 |
| 587 | Smith Pipe Of Abilene | Abilene, TX 79608 | Oil & Gas Operator | Apr 2024 |
| 588 | Smith Production Co. | Wichita Falls, TX 76308 | Oil & Gas Operator | Apr 2024 |
| 589 | Smith Production Inc. | The Woodlands, TX 77381 | Oil & Gas Operator | Apr 2024 |
| 590 | Smith Resources, Inc. | Marshall, TX 75671 | Oil & Gas Operator | Apr 2024 |
| 591 | Smith Resources, L.L.C. | Marshall, TX 75671 | Oil & Gas Operator | Apr 2024 |
| 592 | Smith Vacuum Service | Snyder, TX 79549 | Oil & Gas Operator | Apr 2024 |
| 593 | Smith, David | Wichita Falls, TX 76310 | Oil Operator | Apr 2024 |
| 594 | Smith, E. J. | Fort Worth, TX 76137 | Oil & Gas Operator | Apr 2024 |
| 595 | Smith, E.N. III Energy Corp. | Marshall, TX 75671 | Oil & Gas Operator | Sep 2006 |
| 596 | Smith, Joe H. | Argyle, TX 76226 | Oil & Gas Operator | Nov 1998 |
| 597 | Smith, John A. | Midland, TX 79702 | Oil & Gas Operator | Apr 2024 |
| 598 | Smith, L C Production | Jacksonville, TX 75766 | Oil Operator | Apr 2024 |
| 599 | Smith, L. C. | Jacksonville, TX 75766 | Oil & Gas Operator | Apr 2024 |
| 600 | Smith, O. Dale & Smith, A. C. | Amarillo, TX 79110 | Oil & Gas Operator | Mar 2000 |