| 701 | Mobil Oil E & P Southeast Inc | | Oil & Gas Operator | Sep 2013 |
| 702 | Mobley Oil Company, Inc. | | Oil & Gas Operator | Feb 1990 |
| 703 | Mobley Valve Service, Inc. | | Oil & Gas Operator | Nov 2006 |
| 704 | Monroe Well Ser-Amsterdam | | Oil Operator | Dec 1988 |
| 705 | Monroe Well Ser-La Petro II | | Oil Operator | Dec 1988 |
| 706 | Monroe Well Ser-New American85 | | Oil Operator | Dec 1988 |
| 707 | Monroe Well Ser-Ocean Petr '84 | | Oil & Gas Operator | Dec 1988 |
| 708 | Monroe Well Ser-Ocean Yacht II | | Oil Operator | May 1989 |
| 709 | Monroe Well Ser-Oceanyacht1985 | | Oil Operator | Dec 1988 |
| 710 | Monroe Well Ser-Riverside 1985 | | Oil Operator | Dec 1988 |
| 711 | Monroe Well Serv-New American | | Oil Operator | Dec 1988 |
| 712 | Monroe Well Serv-Northern La | | Oil Operator | Dec 1988 |
| 713 | Monroe Well Serv-Omega 1985 | | Oil Operator | Dec 1988 |
| 714 | Monroe Well Service | | Oil & Gas Operator | Apr 1998 |
| 715 | Monroe Well Service-Apk | | Oil Operator | Dec 1988 |
| 716 | Monroe Well Service-Beaver1985 | | Oil Operator | Nov 1991 |
| 717 | Monroe Well Service-Broadway | | Oil Operator | Dec 1988 |
| 718 | Monroe Well Service-Das | | Oil Operator | Mar 1989 |
| 719 | Monroe Well Service-Derrick | | Oil Operator | Dec 1988 |
| 720 | Monroe Well Service-East End | | Oil Operator | Dec 1988 |
| 721 | Monroe Well Service-Empire | | Oil Operator | Dec 1988 |
| 722 | Monroe Well Service-Energy 84 | | Oil Operator | Aug 1989 |
| 723 | Monroe Well Service-Ged | | Oil Operator | Dec 1988 |
| 724 | Monroe Well Service-Gotham | | Oil Operator | Apr 1992 |
| 725 | Monroe Well Service-Gramercy | | Oil Operator | May 1992 |
| 726 | Monroe Well Service-HGC | | Oil Operator | Dec 1988 |
| 727 | Monroe Well Service-Lebo | | Oil Operator | Jun 1989 |
| 728 | Monroe Well Service-Newtown | | Oil Operator | Aug 1990 |
| 729 | Monroe Well Service-Oceanyacht | | Oil Operator | Jan 1989 |
| 730 | Monroe Well Service-Oil City | | Oil Operator | Aug 1992 |
| 731 | Monroe Well Service-Omega | | Oil Operator | Aug 1992 |
| 732 | Monroe Well Service-Par | | Oil Operator | Jan 1990 |
| 733 | Monroe Well Service-Petrol | | Oil Operator | Sep 1992 |
| 734 | Monroe Well Service-Petrovest | | Oil Operator | Dec 1988 |
| 735 | Monroe Well Service-PRG | | Oil Operator | Nov 1990 |
| 736 | Monroe Well Service-Redstone | | Oil Operator | Jul 1989 |
| 737 | Monroe Well Service-RVS | | Oil Operator | Dec 1990 |
| 738 | Monroe Well Service-Shemen1984 | | Oil Operator | Jan 1989 |
| 739 | Monroe Well Service-Shemen1985 | | Oil Operator | Nov 1990 |
| 740 | Monroe Well Service-Sla | | Oil Operator | Mar 1989 |
| 741 | Monroe Well Service-SPD | | Oil Operator | Dec 1988 |
| 742 | Monroe Well Service-SPD 1985 | | Oil Operator | Dec 1988 |
| 743 | Monroe Well Service-TG I | | Oil Operator | Oct 1990 |
| 744 | Monroe Well Service-TG II | | Oil Operator | Oct 1990 |
| 745 | Monroe Well Service-TG III | | Oil Operator | Jul 1992 |
| 746 | Monroe Well Service-TG VI | | Oil Operator | Aug 1989 |
| 747 | Monroe Well Service-Vista | | Oil Operator | Nov 1990 |
| 748 | Monroe Well Service-West End | | Oil Operator | Dec 1988 |
| 749 | Monterey Resources LLC | Dallas, TX 75230 | Oil & Gas Operator | Oct 2019 |
| 750 | Mooringsport Energy Prod Corp | | Oil & Gas Operator | Oct 1994 |
| 751 | Mooringsport Energy Trans Corp | | Oil Operator | Apr 1990 |
| 752 | Moransco Energy Corporation | Kilgore, TX 75663 | Oil & Gas Operator | Apr 2026 |
| 753 | Moseley Petroleum Corp. | | Oil & Gas Operator | Apr 1988 |
| 754 | MRD Operating LLC | | Oil & Gas Operator | Dec 2016 |
| 755 | Muslow And Parker | | Oil & Gas Operator | Jul 1994 |
| 756 | Muslow Oil Industries | | Oil Operator | Jan 1995 |
| 757 | MW Petroleum Corporation | Houston, TX 77056 | Oil & Gas Operator | Mar 2015 |
| 758 | N. E. Loomis | | Oil Operator | Oct 1986 |
| 759 | N. J. Pardue | | Oil & Gas Operator | Jul 1994 |
| 760 | Nacatosh Gas Incorporated | | Oil & Gas Operator | Aug 2013 |
| 761 | Nadel & Gussman-Jetta Oper. Co. | | Oil & Gas Operator | Mar 2012 |
| 762 | Nadel And Gussman LLC | Tulsa, OK 74119 | Oil & Gas Operator | Apr 2026 |
| 763 | Nadel And Gussman Ruston, LLC | | Oil & Gas Operator | Dec 2024 |
| 764 | Nathan C. Hale | | Oil & Gas Operator | Jan 2025 |
| 765 | Nathan Hale Oil Co. | | Oil & Gas Operator | Jan 2025 |
| 766 | Natural Gas Systems, Inc. | | Oil & Gas Operator | Dec 2002 |
| 767 | Nearburg Producing Company | Dallas, TX 75380 | Oil & Gas Operator | Apr 2026 |
| 768 | Nelson Oil & Gas, Inc. | | Oil & Gas Operator | Aug 1995 |
| 769 | Nerco Oil & Gas Inc | | Oil & Gas Operator | Dec 1996 |
| 770 | New Century Exploration, Inc. | Spring, TX 77379 | Oil & Gas Operator | Apr 2026 |
| 771 | NGC Energy Company | | Oil & Gas Operator | May 1989 |
| 772 | Nichols Oil & Gas Corporation | Shreveport, LA 71135 | Oil & Gas Operator | Aug 2003 |
| 773 | Noram Field Services Corp. | | Oil Operator | Apr 1999 |
| 774 | North American Royalties, Inc. | Chattanooga, TN 37408 | Oil & Gas Operator | Oct 2001 |
| 775 | Northeast Resources | | Oil & Gas Operator | Jan 1992 |
| 776 | Northern Energy Management | | Oil & Gas Operator | Nov 2019 |
| 777 | Northla Productions, LLC | | Oil & Gas Operator | Dec 2024 |
| 778 | Northwest Louisiana Production LLC | | Oil & Gas Operator | Dec 2024 |
| 779 | Novy Oil & Gas, Inc. | Goddard, KS 67052 | Oil & Gas Operator | Feb 2026 |
| 780 | O'Brien Energy Company | Shreveport, LA 71136 | Oil & Gas Operator | Sep 2019 |
| 781 | O. B. And Keith Whatley | | Oil Operator | Jul 1993 |
| 782 | O. B. Beck | | Oil Operator | Feb 1991 |
| 783 | O. B. Mobley | | Oil & Gas Operator | Jul 1989 |
| 784 | O. B. Whatley | | Oil Operator | Jul 1993 |
| 785 | O. F. H., Inc. | | Oil Operator | May 1990 |
| 786 | O.B. Whatley Oil Company, Inc. | | Oil Operator | Feb 2013 |
| 787 | O.B., Keith & Owen B. Whatley | | Oil Operator | Jul 1989 |
| 788 | Oak Valley Operating, LLC | The Woodlands, TX 77380 | Oil & Gas Operator | Jun 2015 |
| 789 | Ocean Energy Inc | Houston, TX 77002 | Oil & Gas Operator | Aug 2003 |
| 790 | Oil & Gas Producers, Inc | Topeka, KS 66604 | Oil Operator | Jun 2004 |
| 791 | Oil Country Management, Inc. | | Oil & Gas Operator | Jan 2005 |
| 792 | Oil Lift Inc | Metairie, LA 70002 | Oil & Gas Operator | Apr 2020 |
| 793 | Oil Reserves Corp Of America | | Oil & Gas Operator | May 2002 |
| 794 | Oil,Gas & Other Minerals, Inc. | | Oil & Gas Operator | Apr 1996 |
| 795 | Ok Oil Company, Inc. | Bivins, TX 75555 | Oil & Gas Operator | Feb 2013 |
| 796 | Ok-La-Tex Production, Inc. | | Oil & Gas Operator | Jan 1982 |
| 797 | Okie Crude Company | Tulsa, OK 74103 | Oil & Gas Operator | Jan 2026 |
| 798 | Omega Energy Incorporated | | Oil & Gas Operator | May 1998 |
| 799 | Ora Oil Company | | Oil & Gas Operator | May 2017 |
| 800 | Orx Resources, L.L.C. | Houston, TX 77067 | Oil & Gas Operator | Apr 2026 |