| 601 | Burkhart Petroleum Corporation | Tulsa, OK 74136 | Oil & Gas Operator | Feb 2002 |
| 602 | Burlington Res Offshore Inc | | Oil & Gas Operator | Oct 2002 |
| 603 | Burlington Res Oil & Gas Co | | Oil & Gas Operator | Dec 2000 |
| 604 | Burlington Res Oil & Gas LP | Houston, TX 77079 | Oil & Gas Operator | Jan 2025 |
| 605 | Burnett Oil Co Inc | Fort Worth, TX 76102 | Oil & Gas Operator | May 2025 |
| 606 | Burnham & Browning DRLG Co. | | Oil Operator | Oct 1990 |
| 607 | Burns Oil & Gas Expl. | | Oil & Gas Operator | Jan 1985 |
| 608 | Burrill Oil | | Oil Operator | Aug 1990 |
| 609 | Burrite Operating, LLC | | Oil Operator | Dec 2024 |
| 610 | Burton-Sutton Oil Co., Inc. | | Oil & Gas Operator | Apr 1988 |
| 611 | Bushwood Leasing, LLC | | Oil Operator | Dec 2024 |
| 612 | Buttes Resources Company | Houston, TX 77056 | Oil & Gas Operator | May 2007 |
| 613 | Byargeon & Sons Oil Co. | | Oil Operator | Nov 2000 |
| 614 | Byron Ruple | | Oil Operator | Jan 2025 |
| 615 | C & B Exploration Company, Inc. | | Oil & Gas Operator | Oct 2008 |
| 616 | C & B Oil Company | Drumright, OK 74030 | Oil & Gas Operator | Mar 2025 |
| 617 | C & B Production | Ben Bolt, TX 78342 | Oil & Gas Operator | May 2025 |
| 618 | C & C Oil & Gas | Ranger, TX 76470 | Oil & Gas Operator | May 2025 |
| 619 | C & C Operating, Inc. | | Oil Operator | Dec 2024 |
| 620 | C & D Resources, Inc. | | Oil & Gas Operator | Nov 2001 |
| 621 | C & E Oil Company | Corpus Christi, TX 78418 | Oil Operator | Jan 1989 |
| 622 | C & F Oil Company, Inc. | | Oil Operator | Jan 2025 |
| 623 | C & F Petroleum | | Oil & Gas Operator | Apr 1991 |
| 624 | C & H Oil Company | Ratliff City, OK 73481-0130 | Oil & Gas Operator | Apr 2015 |
| 625 | C & K Offshore Company | | Oil & Gas Operator | Oct 1980 |
| 626 | C & K Petroleum Inc | Denver, CO 80202 | Oil & Gas Operator | Apr 1984 |
| 627 | C & L Oil Company | Cross Plains, TX 76443 | Oil & Gas Operator | May 2025 |
| 628 | C & M Operating Company | Graham, TX 76450 | Oil & Gas Operator | Feb 2025 |
| 629 | C & N Royalties, L.L.C. | | Oil & Gas Operator | Oct 2015 |
| 630 | C & R Oil | | Oil Operator | Jan 2025 |
| 631 | C & S Oil Company | Odessa, TX 79763 | Oil & Gas Operator | Nov 2019 |
| 632 | C & S Properties | | Oil & Gas Operator | Jun 1996 |
| 633 | C & VC, Inc. | | Oil & Gas Operator | Sep 1991 |
| 634 | C C Co | Holladay, UT 84124 | Oil & Gas Operator | Jan 2020 |
| 635 | C G Davis, Et Al | | Oil & Gas Operator | Mar 1986 |
| 636 | C S Petroleum Inc | Norman, OK 73070 | Oil & Gas Operator | Dec 2024 |
| 637 | C&M Operating Company, LLC | | Oil & Gas Operator | Apr 2011 |
| 638 | C. A. Cardneaux, Inc. | | Oil & Gas Operator | Apr 1990 |
| 639 | C. D. Pierce | | Oil Operator | Mar 1991 |
| 640 | C. H. C. Gerard | | Oil & Gas Operator | Jan 2025 |
| 641 | C. H. Cuatro | | Gas Operator | Sep 1996 |
| 642 | C. J. Broome Oil Company | | Oil & Gas Operator | Jan 2020 |
| 643 | C. L. Brown, III | | Oil Operator | Dec 1991 |
| 644 | C. L. Brown, Inc. | | Oil Operator | Dec 1999 |
| 645 | C. L. Morris | | Oil Operator | Feb 2004 |
| 646 | C. L. Morris, Inc. | | Oil & Gas Operator | Feb 2004 |
| 647 | C. M. Frizzell | | Oil & Gas Operator | Mar 2014 |
| 648 | C. M. Roberson | | Oil Operator | Jun 1984 |
| 649 | C. Smith & Associates, Inc. | | Oil Operator | Aug 1991 |
| 650 | C. T. & Ted Paul | | Oil Operator | Mar 2019 |
| 651 | C. V. Radke | | Oil Operator | Jan 1993 |
| 652 | C. W. Brumley | | Oil & Gas Operator | Jun 2006 |
| 653 | C. W. Resources, Inc. | Longview, TX 75604 | Oil & Gas Operator | May 2025 |
| 654 | C. Wayland Brooks | | Oil & Gas Operator | Dec 1987 |
| 655 | C.B.C. Producing Co. | | Oil & Gas Operator | Jul 1989 |
| 656 | C.F. Braun & Company | | Oil & Gas Operator | Dec 1986 |
| 657 | C.F.D. Inc. | | Oil & Gas Operator | Nov 1988 |
| 658 | C.J. Oil Company | Iowa Park, TX 76367 | Oil Operator | Dec 2024 |
| 659 | C.P.I. | | Oil & Gas Operator | Oct 2007 |
| 660 | C.T.R. Oil, Inc. | | Oil & Gas Operator | Jan 2025 |
| 661 | C.W.F.K., Inc. | | Gas Operator | Dec 1986 |
| 662 | C6 Operating, L.L.C. | Keatchie, LA 71046 | Oil & Gas Operator | May 2025 |
| 663 | Caba, LLC | | Oil Operator | Jan 2025 |
| 664 | Cabot Oil & Gas Corporation | Houston, TX 77024 | Oil & Gas Operator | Feb 2025 |
| 665 | Cabot Petroleum Corporation | Englewood, CO 80111-2529 | Oil & Gas Operator | Dec 2004 |
| 666 | Caddeaux Gathering, LLC | | Oil Operator | Dec 2024 |
| 667 | Caddo Gas Processing L.L.C. | | Oil Operator | Aug 2012 |
| 668 | Caddo Management, Inc | Shreveport, LA 71101 | Oil & Gas Operator | Jan 2025 |
| 669 | Caddo Oil & Gas Co., Inc. | | Oil Operator | Jul 1990 |
| 670 | Caddo Oil Co.,Inc. | | Oil & Gas Operator | Apr 1987 |
| 671 | Caddo Parish Holdings LLC | | Oil & Gas Operator | Jul 2020 |
| 672 | Caddo Petroleum Dev., Inc. | | Oil Operator | Aug 1986 |
| 673 | Caddo Pine Island Corp. | | Oil & Gas Operator | Sep 1997 |
| 674 | Caddo Pine Island Operating Co | | Oil & Gas Operator | Aug 1998 |
| 675 | Caddo Resources Inc | | Oil & Gas Operator | Dec 1986 |
| 676 | Caddo Western Development, Inc | | Oil & Gas Operator | Aug 1984 |
| 677 | Cadillac Operating Company, LLC | | Oil Operator | Jan 2025 |
| 678 | Cairn Energy Partners, LLC | | Oil & Gas Operator | Feb 2023 |
| 679 | Cajun Minerals, Inc. | | Oil & Gas Operator | Mar 1997 |
| 680 | Cajun Operating, Inc. | | Oil & Gas Operator | Jun 2011 |
| 681 | Cala Oil & Gas | | Oil & Gas Operator | Oct 1997 |
| 682 | Calais Oil & Gas, L.L.C. | | Oil Operator | Dec 2024 |
| 683 | Caldwell & Self | | Oil Operator | Dec 2024 |
| 684 | Caldwell & Trahan | | Oil Operator | Dec 2024 |
| 685 | Caldwell Oil Company | | Oil Operator | Jul 2012 |
| 686 | Caldwell Operating, L.L.C. | | Oil Operator | Dec 2024 |
| 687 | Caldwell Production | | Oil Operator | Dec 2024 |
| 688 | Caldwell-Bayou State | | Oil Operator | Dec 2024 |
| 689 | California Time Petroleum, Inc | | Oil Operator | Mar 1986 |
| 690 | Callon Offshore Production, Inc. | Natchez, MS 39121 | Oil & Gas Operator | Dec 2005 |
| 691 | Callon Petroleum Company | Natchez, MS 39120 | Oil & Gas Operator | Jan 2000 |
| 692 | Callon Petroleum Operating Co | Houston, TX 77042 | Oil & Gas Operator | Jul 2024 |
| 693 | Calpetco III-Teel 77 A | | Gas Operator | May 1980 |
| 694 | Calpetco-Herbst Expl. Inc. | | Gas Operator | Jan 1990 |
| 695 | Calpine Natural Gas Company | Houston, TX 77002 | Oil & Gas Operator | Apr 2002 |
| 696 | Calpine Natural Gas Company L.P. | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 697 | Calpine Natural Gas L.P. | Houston, TX 77002 | Oil & Gas Operator | Jan 2006 |
| 698 | Calto Operating Company, Inc. | Dallas, TX 75225 | Oil & Gas Operator | May 2004 |
| 699 | Calumet Lubricants Company | | Oil Operator | Dec 1993 |
| 700 | Calumet Refining Co. | | Oil Operator | May 1991 |