| 501 | Tonto Petroleum Corporation | Post, TX 79356 | Oil & Gas Operator | Jan 2007 |
| 502 | Toomey Oil Company Inc | Tulsa, OK 74101-1090 | Oil & Gas Operator | Feb 2024 |
| 503 | Top O'Texas Production Co. | Pampa, TX 79066 | Oil & Gas Operator | Apr 2024 |
| 504 | Top Op, L.L.C. | Houston, TX 77077 | Oil & Gas Operator | May 2020 |
| 505 | Topat Oil Corporation | Midland, TX 79701 | Oil & Gas Operator | Sep 2017 |
| 506 | Topaz Oil Company | Diboll, TX 75941 | Oil & Gas Operator | Apr 1994 |
| 507 | Topper Oil Company | Borger, TX 79007 | Oil & Gas Operator | Apr 2024 |
| 508 | Tor Energy, LLC | Temple, TX 76501 | Oil & Gas Operator | Apr 2024 |
| 509 | Torch Energy Services, Inc. | Houston, TX 77010 | Oil & Gas Operator | Sep 2011 |
| 510 | Torch Oil & Gas Company | Houston, TX 77010 | Oil & Gas Operator | Aug 1997 |
| 511 | Torch Operating Company | Houston, TX 77010 | Oil & Gas Operator | Mar 2015 |
| 512 | Torch Operating LLC | Fort Worth, TX 76135 | Oil & Gas Operator | Oct 2020 |
| 513 | Toreador Exploration & Prod Inc | Dallas, TX 75240 | Oil & Gas Operator | Feb 2008 |
| 514 | Torrent Oil LLC | Houston, TX 77002 | Oil & Gas Operator | Apr 2024 |
| 515 | Tortuga Operating Company | Houston, TX 77055 | Oil & Gas Operator | Apr 2024 |
| 516 | Total E&P USA, Inc. | Houston, TX 77210 | Oil & Gas Operator | Nov 2011 |
| 517 | Total Minatome Corporation | Houston, TX 77210 | Oil & Gas Operator | Dec 1998 |
| 518 | Totalfinaelf E&P USA Inc | Houston, TX 77024 | Oil & Gas Operator | Jul 2007 |
| 519 | Touchstone Resources USA, Inc. | Houston, TX 77002 | Oil & Gas Operator | Oct 2006 |
| 520 | Tower Resources Inc | Conroe, TX 77304 | Oil & Gas Operator | Apr 2024 |
| 521 | Townes, Don | Clarksville, TX 75426 | Oil & Gas Operator | Apr 2024 |
| 522 | Townsend Company | Abilene, TX 79608 | Oil & Gas Operator | Dec 2021 |
| 523 | Townsend, R. F. Trustee | Dallas, TX 75201 | Oil & Gas Operator | Dec 1994 |
| 524 | TPC Exploration, LLC | May, TX 76857 | Oil & Gas Operator | Apr 2024 |
| 525 | Tpet Management Inc. | Dallas, TX 75204 | Oil & Gas Operator | Dec 1997 |
| 526 | Tpet, Inc. | Dallas, TX 75204 | Oil & Gas Operator | Mar 2008 |
| 527 | TR Offshore, LLC | Corpus Chrsti, TX 78413 | Oil & Gas Operator | Apr 2024 |
| 528 | TR Operating LLC | Graham, TX 76450 | Oil Operator | Mar 2024 |
| 529 | Trace Energy Management Inc | Weatherford, TX 76086 | Oil & Gas Operator | Apr 2024 |
| 530 | Trace Operating, LLC | Fort Worth, TX 76116 | Oil & Gas Operator | Apr 2024 |
| 531 | Tracer Energy, Inc. | Graham, TX 76450 | Oil & Gas Operator | Nov 1998 |
| 532 | Tracer Operating, Inc. | Graham, TX 76450 | Oil & Gas Operator | Apr 2024 |
| 533 | Tracker Mineral | Clyde, TX 79510 | Oil & Gas Operator | Apr 2024 |
| 534 | Tracker Oil & Gas, Inc. | Bastrop, TX 78602 | Oil & Gas Operator | Apr 2024 |
| 535 | Tracker Resource Dev III, LLC | Englewood, CO 80112 | Oil & Gas Operator | Jul 2021 |
| 536 | Trackstar Energies LLC | Colorado Springs, CO 80919 | Oil Operator | Mar 2023 |
| 537 | Tracy Co. | Rockdale, TX 76567 | Oil & Gas Operator | Mar 2022 |
| 538 | Tracy Operating Co., LLC | Rockdale, TX 76567 | Oil & Gas Operator | Apr 2024 |
| 539 | Tracy Production | Lindale, TX 75771 | Oil & Gas Operator | Apr 2024 |
| 540 | Tradestar Energy, Inc. | Hot Springs, AR 71913 | Oil Operator | Feb 2021 |
| 541 | Tradition Resources LLC | Houston, TX 77002 | Oil & Gas Operator | Jan 2014 |
| 542 | Tradition Resources Oper, LLC | Houston, TX 77002 | Oil & Gas Operator | Jul 2017 |
| 543 | Trail Mountain, Inc. | Artesia, NM 88210 | Oil & Gas Operator | Jan 2016 |
| 544 | Trail Ridge Energy Partners, LLC | Grapevine, TX 76051 | Oil & Gas Operator | Feb 2024 |
| 545 | Trail Ridge Energy PRTNS II LLC | Grapevine, TX 76051 | Oil & Gas Operator | Jun 2017 |
| 546 | Trailblazer Energy LLC | Plano, TX 75075 | Oil & Gas Operator | Feb 2024 |
| 547 | Trailblazer Energy Resources, LLC | Tulsa, OK 74136 | Oil & Gas Operator | Apr 2024 |
| 548 | Trans Ocean Oil, Inc. | Houston, TX 77252 | Oil & Gas Operator | Oct 1980 |
| 549 | Trans Oil Marketing LLC | Abilene, TX 79602 | Oil Operator | Aug 2023 |
| 550 | Trans Terra Corp., International | Amarillo, TX 79159 | Oil & Gas Operator | Feb 2009 |
| 551 | Trans Texas Minerals Company | Austin, TX 78714 | Oil & Gas Operator | Aug 1999 |
| 552 | Trans-Pecos Resources, Inc. | Houston, TX 77056 | Oil & Gas Operator | Apr 2024 |
| 553 | Trans-Texas Energy Group LLC | Mineral Wells, TX 76068 | Oil & Gas Operator | Jul 2015 |
| 554 | Transamerica Energy Corp. | Atlanta, GA 30356 | Oil & Gas Operator | Apr 2024 |
| 555 | Transamerican Natural Gas Corp. | Houston, TX 77032 | Oil & Gas Operator | Aug 2000 |
| 556 | Transatlantic Petr (USA) Corp. | Dallas, TX 75206 | Oil & Gas Operator | Apr 2024 |
| 557 | Transcontinental Minerals Corp. | The Woodlands, TX 77380 | Oil & Gas Operator | Dec 2008 |
| 558 | Transcontinental Shale L.L.C. | Austin, TX 78717 | Oil & Gas Operator | Feb 2016 |
| 559 | Transfuel Resources Co | Houston, TX 77215 | Oil & Gas Operator | Aug 2013 |
| 560 | Transoil, Inc. | Oklahoma City, OK 73129 | Oil & Gas Operator | Apr 2024 |
| 561 | Transpacific Energy, LLC | Katy, TX 77450 | Oil & Gas Operator | Apr 2024 |
| 562 | Transpetco I | Shreveport, LA 71101 | Oil & Gas Operator | May 2009 |
| 563 | Transtexas Gas Corporation | Houston, TX 77265 | Oil & Gas Operator | Aug 2005 |
| 564 | Trap Rock Oil Company | Cambridge, MA 02138 | Oil & Gas Operator | Nov 2005 |
| 565 | Trap Rock Oil, LTD. | Houston, TX 77027 | Oil & Gas Operator | Apr 2024 |
| 566 | Traton Operating Company | Kingwood, TX 77339 | Oil & Gas Operator | Mar 2019 |
| 567 | Travelers Oil Company | Amarillo, TX 79102 | Oil & Gas Operator | Apr 2024 |
| 568 | Travers Resources, Inc. | Houston, TX 77056 | Oil & Gas Operator | Apr 2024 |
| 569 | Travis | Houston, TX 77057 | Oil Operator | Apr 2024 |
| 570 | Travis Operating, LLC | Kingwood, TX 77345 | Oil & Gas Operator | Apr 2024 |
| 571 | Travis, J. J., Trustee | Rockport, TX 78382 | Oil & Gas Operator | Dec 1996 |
| 572 | Treadaway Oil Co. | Balmorhea, TX 79718 | Oil & Gas Operator | Apr 2024 |
| 573 | Treadstone Energy Partners, LLC | Houston, TX 77070 | Oil & Gas Operator | Jun 2016 |
| 574 | Treadstone Energy PRTNR Op, LLC | Katy, TX 77494 | Oil & Gas Operator | Apr 2024 |
| 575 | Treco Oil Company | Albany, TX 76430 | Oil & Gas Operator | Apr 2024 |
| 576 | Tree Operating, LLC | Graham, TX 76450 | Oil & Gas Operator | Apr 2024 |
| 577 | Trejim Operators, LLC | Pampa, TX 79065 | Oil & Gas Operator | Apr 2024 |
| 578 | Trek Aec, LLC | Wichita, KS 67202 | Oil & Gas Operator | Dec 2023 |
| 579 | Trek Exploration, Inc. | Amarillo, TX 79109 | Oil & Gas Operator | Apr 2024 |
| 580 | Trek Oil & Gas, Inc | Houston, TX 77002 | Oil Operator | Mar 1998 |
| 581 | Trek Resources, Inc. | Dallas, TX 75207 | Oil & Gas Operator | Apr 2024 |
| 582 | Trend Exploration Company | Midland, TX 79701 | Oil & Gas Operator | Mar 2008 |
| 583 | Trend Exploration I LLC | Midland, TX 79701 | Oil & Gas Operator | May 2011 |
| 584 | Trenna Oil Inc. | Midland, TX 79702 | Oil & Gas Operator | Dec 2013 |
| 585 | Tres Azores Oil & Gas, Inc. | Fort Worth, TX 76185 | Oil & Gas Operator | Aug 2003 |
| 586 | Tres Operating Co., LLC | Katy, TX 77494 | Oil Operator | Apr 2024 |
| 587 | Tres Piedras, Inc. | Wichita Falls, TX 76301 | Oil & Gas Operator | Apr 1999 |
| 588 | Tres Roughneckas WTX LLC | Houston, TX 77009 | Oil Operator | Apr 2024 |
| 589 | Tresami, Inc. | Jacksboro, TX 76458 | Oil & Gas Operator | Apr 2024 |
| 590 | Trey Exploration, Inc. | San Angelo, TX 76901 | Oil & Gas Operator | Dec 2020 |
| 591 | Trey Operating Company | MC Camey, TX 79752 | Oil Operator | Jan 2016 |
| 592 | Trey Resources Inc. | Midland, TX 79710 | Oil & Gas Operator | Jan 2024 |
| 593 | Tri "M" Oil & Gas | Muenster, TX 76252 | Oil & Gas Operator | Apr 2024 |
| 594 | Tri City Oil Co., LLC | Baytown, TX 77520 | Oil Operator | Apr 2024 |
| 595 | Tri Energy Resources, Inc. | Norman, OK 73070 | Oil Operator | Apr 2024 |
| 596 | Tri Sportsmen Energy, Inc. | Austin, TX 78746 | Oil & Gas Operator | Apr 2024 |
| 597 | Tri Star Operating, Inc. | Arlington, TX 76012 | Oil & Gas Operator | Jan 2002 |
| 598 | Tri-Am Operating Company | Frankston, TX 75763 | Oil & Gas Operator | Apr 2024 |
| 599 | Tri-C Resources, Inc. | Houston, TX 77024 | Oil & Gas Operator | Aug 2009 |
| 600 | Tri-C Resources, LLC | Houston, TX 77024 | Oil & Gas Operator | Apr 2024 |