| 501 | Team Operating, L.L.C. | Pinehurst, TX 77362 | Oil & Gas Operator | Apr 2024 |
| 502 | Tellus Operating Group, LLC | | Oil & Gas Operator | Jan 2024 |
| 503 | Temple Oil Co | | Oil & Gas Operator | Oct 1992 |
| 504 | Terry Sims & Associates, Inc. | | Oil Operator | Sep 2009 |
| 505 | Tesoro Petroleum Corporation | | Oil & Gas Operator | May 1982 |
| 506 | Texaco E & P Inc | Houston, TX 77099 | Oil & Gas Operator | Apr 2024 |
| 507 | Texaco Inc | Kingfisher, OK 73750 | Oil & Gas Operator | Dec 2017 |
| 508 | Texaco Seaboard, Inc. | | Gas Operator | Sep 1980 |
| 509 | Texas Petroleum Investment Company | Houston, TX 77057 | Oil & Gas Operator | Apr 2024 |
| 510 | Thaxton Operating | | Oil Operator | Jan 1994 |
| 511 | Thomas A. Blanton | | Oil Operator | Nov 2023 |
| 512 | Thunder Oil, LLC | | Oil & Gas Operator | Oct 1998 |
| 513 | Tiger Production Company, LLC | | Oil & Gas Operator | Aug 2021 |
| 514 | Tigrett, Terry A. Jr. | | Oil & Gas Operator | Oct 1980 |
| 515 | Tilghman Operating, LLC. | | Oil & Gas Operator | Feb 2024 |
| 516 | TNT Operating LLC | | Oil & Gas Operator | Aug 2016 |
| 517 | Tomlinson Interests | | Oil & Gas Operator | Jan 1983 |
| 518 | Tops Operating Co.,Inc. | | Oil Operator | Dec 1985 |
| 519 | Transcontinental Oil Corp. | | Oil & Gas Operator | Sep 1985 |
| 520 | Trendsetter Production Co, Inc | | Oil & Gas Operator | Jul 2008 |
| 521 | Tri-Quest Resources | | Oil & Gas Operator | Feb 1995 |
| 522 | Triad Oil & Gas Co Inc | | Oil & Gas Operator | Jun 1994 |
| 523 | Triangle Oil Producers, Inc. | | Oil & Gas Operator | Jun 1998 |
| 524 | Trident Oil And Gas Corp. | | Oil & Gas Operator | Sep 2000 |
| 525 | Trinity Oil & Gas Dev Inc | | Oil & Gas Operator | Jun 1994 |
| 526 | Trio Operating Company, Inc. | Wichita Falls, TX 76307 | Oil & Gas Operator | Apr 2006 |
| 527 | Tuway Oil, Inc | | Oil & Gas Operator | Jun 2006 |
| 528 | Txo Production Corp. | Ganado, TX 77962 | Oil & Gas Operator | Aug 2022 |
| 529 | Ultramar Oil & Gas LTD | Houston, TX 77060 | Oil & Gas Operator | Jul 1995 |
| 530 | Umc Petroleum Corporation | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 531 | Unit Petroleum Company | Tulsa, OK 74170 | Oil & Gas Operator | Apr 2024 |
| 532 | Unocal Explor. Corp. | | Oil & Gas Operator | Nov 1990 |
| 533 | Ventex Operating Corp. | Addison, TX 75001 | Oil & Gas Operator | Apr 2024 |
| 534 | Venture Oil & Gas, Inc. | Laurel, MS 39440 | Oil & Gas Operator | Jan 2024 |
| 535 | Vernon E. Faulconer, Inc. | Tyler, TX 75711 | Oil & Gas Operator | Dec 2023 |
| 536 | Veron E.Faulconer Inc | | Oil & Gas Operator | Nov 1989 |
| 537 | Vicksburg Refining, Inc. -Jackson | | Oil Operator | Apr 1984 |
| 538 | Vicksburg Refining, Inc. -Vicksburg | | Oil Operator | Apr 1984 |
| 539 | Victor Producers , LLC. | | Oil & Gas Operator | Feb 2024 |
| 540 | Vines Operating, LLC | | Oil Operator | Jun 2017 |
| 541 | Vintage Petroleum | | Oil & Gas Operator | Feb 2003 |
| 542 | Vonco Of Mississippi, Inc. | | Oil Operator | Jan 2024 |
| 543 | W. E. O'Malley, Inc. | | Oil & Gas Operator | Jun 1991 |
| 544 | W.I.F.T. Operating, LLC | | Oil & Gas Operator | Feb 2024 |
| 545 | W.S. Red Hancock, Inc. | | Oil Operator | Dec 1986 |
| 546 | Waco Corp | | Oil Operator | Jun 1983 |
| 547 | Wagner Oil Company | Fort Worth, TX 76102 | Oil & Gas Operator | Apr 2024 |
| 548 | Waller Brothers, Inc. | | Oil & Gas Operator | Jul 2004 |
| 549 | Watchtower Petroleum, LLC | | Oil & Gas Operator | Feb 2024 |
| 550 | Weeks Exploration Company | Houston, TX 77063 | Oil & Gas Operator | Aug 1995 |
| 551 | Weiser-Brown Operating Company | Magnolia, AR 71754 | Oil & Gas Operator | Apr 2024 |
| 552 | Westfield Energy Corp. | | Oil & Gas Operator | Mar 1991 |
| 553 | White River Operating LLC | Gilmer, TX 75644 | Oil & Gas Operator | Jan 2024 |
| 554 | White, Charles R | | Oil Operator | Mar 1987 |
| 555 | Whitehead, Cecil | | Oil Operator | May 1997 |
| 556 | Wickham, R. R. | | Oil Operator | Jan 1980 |
| 557 | Wilcox Energy Company | | Oil & Gas Operator | Feb 2024 |
| 558 | Wilcox Operating Corporation | Shreveport, LA 71115 | Oil & Gas Operator | Apr 2024 |
| 559 | Wilcox Ventures, LLC | | Oil & Gas Operator | Jan 2024 |
| 560 | Will-Drill Production Co., Inc. | Shreveport, LA 71105 | Oil & Gas Operator | Apr 2024 |
| 561 | Williams Producing Co | | Oil & Gas Operator | Dec 2023 |
| 562 | Williams, Kenneth O. Jr | | Oil Operator | Nov 2006 |
| 563 | Womack Energy, Inc. | | Oil & Gas Operator | Nov 2023 |
| 564 | Wyble L. Ollie | | Oil & Gas Operator | Dec 1988 |
| 565 | Xmco Inc | | Oil & Gas Operator | Sep 1986 |
| 566 | Yellow Creek Operating, LLC | | Oil & Gas Operator | Oct 2023 |