| 501 | Tesoro Petroleum | | Oil Operator | Mar 1982 |
| 502 | Tesoro Petroleum Corporation | | Oil & Gas Operator | May 1982 |
| 503 | Tess Oil Company | Borger, TX 79008 | Oil & Gas Operator | Mar 2008 |
| 504 | Tessara Petroleum Resources, LLC | Houston, TX 77086 | Oil & Gas Operator | Apr 2020 |
| 505 | Tessera Energy LLC | | Oil & Gas Operator | Dec 2023 |
| 506 | Testco Production Company | Watonga, OK 73772-0589 | Oil & Gas Operator | Aug 2013 |
| 507 | Tesuque Oil & Gas LLC | Rockdale, TX 76567 | Oil Operator | Apr 2024 |
| 508 | Tet Energy | | Oil Operator | Sep 2023 |
| 509 | Teton Energy Co Inc | Denver, CO 80239 | Oil Operator | Dec 1983 |
| 510 | Teton Petroleum Corporation | Kerrville, TX 78028 | Oil & Gas Operator | Apr 2024 |
| 511 | Tetra Oil Company | | Oil & Gas Operator | Nov 2023 |
| 512 | Tetragon Investments, LLC | Abilene, TX 79604 | Oil Operator | Jul 2014 |
| 513 | Tettleton, Jon Otis | Nocona, TX 76255 | Oil & Gas Operator | Aug 2003 |
| 514 | Tettleton, Steven B. | Nocona, TX 76255 | Oil Operator | Apr 2024 |
| 515 | Tevebaugh MGMT Co | Baden, PA 15005-0123 | Oil & Gas Operator | Dec 2002 |
| 516 | Tex-Am Petroleum Corp. | Eastland, TX 76448 | Oil & Gas Operator | Apr 2024 |
| 517 | Tex-Am-Energy Inc. | Dallas, TX 75205 | Oil & Gas Operator | Mar 2008 |
| 518 | Tex-Ann Oil & Gas Services, Inc. | Abilene, TX 79608 | Oil & Gas Operator | Apr 2024 |
| 519 | Tex-Atic Resources, Inc. | S. Lake Tahoe, CA 96150 | Oil & Gas Operator | Apr 2024 |
| 520 | Tex-Hio Energy | Terrell, TX 75156 | Oil & Gas Operator | Dec 1997 |
| 521 | Tex-Lee Operating Company | Giddings, TX 78942 | Oil & Gas Operator | Apr 2024 |
| 522 | Tex-Oak, Inc. | Oklahoma City, OK 73155 | Oil & Gas Operator | Dec 1995 |
| 523 | Tex-Ok Energy LP | Cody, WY 82414-5915 | Oil & Gas Operator | Jan 2024 |
| 524 | Tex-Ok Energy, LTD Partnership | Cody, WY 82414 | Oil & Gas Operator | Apr 2024 |
| 525 | Tex-Pro Energy Operating, LLC | Kilgore, TX 75663 | Oil Operator | Feb 2023 |
| 526 | Tex-R Energy, Inc. | Abilene, TX 79608 | Oil & Gas Operator | Feb 2021 |
| 527 | Tex-Star Production | Dallas, TX 75360-0577 | Oil & Gas Operator | Jan 2024 |
| 528 | Tex/Con Oil & Gas Company | Houston, TX 77074 | Oil & Gas Operator | Feb 2001 |
| 529 | Texacal, Inc. | Newport Beach, CA 92660 | Oil & Gas Operator | Apr 2024 |
| 530 | Texaco E & P Inc | Houston, TX 77099 | Oil & Gas Operator | Apr 2024 |
| 531 | Texaco Expl. And Prod. Inc. | Houston, TX 77236 | Oil & Gas Operator | Dec 2023 |
| 532 | Texaco Explorati | | Oil & Gas Operator | Dec 1996 |
| 533 | Texaco Exploration & Prod | Midland, TX 79702 | Oil & Gas Operator | Aug 2002 |
| 534 | Texaco Exploration & Production Inc N W | Farmington, NM 87401 | Oil & Gas Operator | Aug 1995 |
| 535 | Texaco Inc | Kingfisher, OK 73750 | Oil & Gas Operator | Dec 2017 |
| 536 | Texaco Inc & A.C. Glassell Jr | | Oil & Gas Operator | Aug 1980 |
| 537 | Texaco Oils, Inc. | Tulsa, OK 74102-2420 | Oil & Gas Operator | Jan 2003 |
| 538 | Texaco Producing Inc. | Rock Springs, WY 82901 | Oil & Gas Operator | Dec 2000 |
| 539 | Texaco Seaboard, Inc. | | Gas Operator | Sep 1980 |
| 540 | Texaco USA - Mor | | Oil Operator | Aug 1988 |
| 541 | Texada Resources, Inc. | | Oil & Gas Operator | Dec 1992 |
| 542 | Texakoma E & P, LLC | Plano, TX 75024 | Oil & Gas Operator | Apr 2024 |
| 543 | Texakoma Exploration & Production LLC | | Oil & Gas Operator | Jan 2024 |
| 544 | Texakoma Oil & Gas Corp | Dallas, TX 75240 | Oil & Gas Operator | Sep 2014 |
| 545 | Texakoma Operating, L.P. | Plano, TX 75024 | Oil & Gas Operator | Apr 2024 |
| 546 | Texakoma Opr LP | Plano, TX 75024 | Oil & Gas Operator | Dec 2012 |
| 547 | Texakota | | Oil & Gas Operator | Mar 1995 |
| 548 | Texakota, Inc. | Houston, TX 77098 | Oil & Gas Operator | Mar 2021 |
| 549 | Texan Petroleum Corporation | Dallas, TX 75204 | Oil & Gas Operator | Oct 2004 |
| 550 | Texan Production | Pearsall, TX 78061 | Oil & Gas Operator | Aug 2003 |
| 551 | Texan Production Company, Inc. | Canyon Lake, TX 78133 | Oil & Gas Operator | Apr 2024 |
| 552 | Texana Operating Company | Houston, TX 77090 | Oil & Gas Operator | Apr 2024 |
| 553 | Texas American Oil Corporation | Midland, TX 79701 | Oil & Gas Operator | Jan 2001 |
| 554 | Texas American Resources Company | Austin, TX 78701 | Oil & Gas Operator | Apr 2024 |
| 555 | Texas City Refining, Inc. | | Oil & Gas Operator | Nov 1988 |
| 556 | Texas Coastal Resources LLC | Fairhope, AL 36532 | Oil Operator | Apr 2024 |
| 557 | Texas Concho Operating Co. | Eldorado, TX 76936 | Oil & Gas Operator | Mar 1999 |
| 558 | Texas Consolidated Pet. Corp. | Fort Worth, TX 76109 | Oil & Gas Operator | Apr 2024 |
| 559 | Texas Crude & Dale Gas Expl | | Oil & Gas Operator | Dec 1984 |
| 560 | Texas Crude Energy, Inc. | Houston, TX 77256 | Oil & Gas Operator | Oct 2012 |
| 561 | Texas Crude Exploration, Inc. | Fort Worth, TX 76116 | Oil & Gas Operator | Aug 1992 |
| 562 | Texas Crude Oil Co. | | Oil & Gas Operator | Jan 1985 |
| 563 | Texas Crude Oil Co. Et Al | | Oil & Gas Operator | May 1992 |
| 564 | Texas Crude Oil, Inc. | | Oil & Gas Operator | Dec 1984 |
| 565 | Texas Crude Operator, Inc. | Houston, TX 77098 | Oil & Gas Operator | Aug 2017 |
| 566 | Texas Crude, Inc. | Houston, TX 77256 | Oil & Gas Operator | Oct 1995 |
| 567 | Texas Crude-Rebstock & Reeves | | Oil & Gas Operator | Feb 1980 |
| 568 | Texas Crude-Wainoco-Hilliard | | Oil & Gas Operator | Jul 1978 |
| 569 | Texas Eastern Skyline Oil | Houston, TX 77252 | Oil & Gas Operator | Jan 1987 |
| 570 | Texas Eastern Transm. Corp. | | Oil & Gas Operator | Dec 2002 |
| 571 | Texas Energies I | | Oil & Gas Operator | Aug 1994 |
| 572 | Texas Energies, Inc. | Pratt, KS 67124 | Oil & Gas Operator | Aug 1998 |
| 573 | Texas Energy & Environmental | Houston, TX 77070 | Oil & Gas Operator | Nov 1998 |
| 574 | Texas Energy & Environmental Inc | Houston, TX 77269 | Oil & Gas Operator | Oct 1998 |
| 575 | Texas Energy Mutual LLC | | Oil Operator | Jun 2018 |
| 576 | Texas Energy Operations, LC | Wichita Falls, TX 76301 | Oil & Gas Operator | Apr 2024 |
| 577 | Texas Energy Sources, Inc. | Midland, TX 79708 | Oil & Gas Operator | Mar 2008 |
| 578 | Texas Energy Trust Company | Midland, TX 79701 | Oil & Gas Operator | Jun 2016 |
| 579 | Texas Exploration & Prod. Co. | Gainesville, TX 76240 | Oil & Gas Operator | Apr 1996 |
| 580 | Texas Fuel Company | Galveston, TX 77550 | Oil & Gas Operator | Apr 2024 |
| 581 | Texas Gas Exploration Corp. | | Oil & Gas Operator | Nov 1986 |
| 582 | Texas Gas Resources, Inc. | Houston, TX 77292 | Oil & Gas Operator | Jul 2009 |
| 583 | Texas Gas Transmission Corp. | | Oil Operator | Aug 2003 |
| 584 | Texas Gas Transmission LLC | Owensboro, KY 42301 | Oil & Gas Operator | Dec 2023 |
| 585 | Texas General Petroleum Corp | | Oil & Gas Operator | Sep 1984 |
| 586 | Texas Gulf Gas Corporation | Fayetteville, TX 78940 | Oil & Gas Operator | Jun 2005 |
| 587 | Texas Hydrogen Energy Corp. | Midland, TX 79702 | Oil & Gas Operator | May 1999 |
| 588 | Texas Ind. Exploration, Inc. | | Oil & Gas Operator | Oct 2001 |
| 589 | Texas Independent Explor LTD. | Houston, TX 77024 | Oil & Gas Operator | Apr 2024 |
| 590 | Texas Independent Explor., Inc. | Houston, TX 77002 | Oil & Gas Operator | Oct 2002 |
| 591 | Texas Independent Exploration LP | Houston, TX 77024 | Oil & Gas Operator | Mar 2017 |
| 592 | Texas Independent Oil Co., LLC | Argyle, TX 76226 | Oil & Gas Operator | Apr 2024 |
| 593 | Texas International Oper., LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Dec 2013 |
| 594 | Texas International Resource LLC | Allen, TX 75013 | Oil Operator | Apr 2024 |
| 595 | Texas Investments | San Angelo, TX 76904 | Oil & Gas Operator | Mar 2008 |
| 596 | Texas JWB LLC | Rowlett, TX 75089 | Oil Operator | Apr 2024 |
| 597 | Texas Keystone Inc | Oakmont, PA 15139-2072 | Oil & Gas Operator | Nov 2017 |
| 598 | Texas Land & Petro Co., LLC | Carrollton, TX 75010 | Oil & Gas Operator | Apr 2024 |
| 599 | Texas Land & Trading Co, Inc. | Austin, TX 78734 | Oil & Gas Operator | Mar 2008 |
| 600 | Texas Lone Star Petroleum Corp. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Dec 2013 |