| 3101 | Monroe Gas Joint Venture | | Gas Operator | Sep 2011 |
| 3102 | Monroe Well Ser-Amsterdam | | Oil Operator | Dec 1988 |
| 3103 | Monroe Well Ser-La Petr Assoc | | Oil Operator | Dec 1988 |
| 3104 | Monroe Well Ser-La Petro II | | Oil Operator | Dec 1988 |
| 3105 | Monroe Well Ser-New American85 | | Oil Operator | Dec 1988 |
| 3106 | Monroe Well Ser-Ocean Petr '84 | | Oil & Gas Operator | Dec 1988 |
| 3107 | Monroe Well Ser-Ocean Yacht II | | Oil Operator | May 1989 |
| 3108 | Monroe Well Ser-Oceanyacht1985 | | Oil Operator | Dec 1988 |
| 3109 | Monroe Well Ser-Riverside 1985 | | Oil Operator | Dec 1988 |
| 3110 | Monroe Well Serv-New American | | Oil Operator | Dec 1988 |
| 3111 | Monroe Well Serv-Northern La | | Oil Operator | Dec 1988 |
| 3112 | Monroe Well Serv-Omega 1985 | | Oil Operator | Dec 1988 |
| 3113 | Monroe Well Service | | Oil & Gas Operator | Apr 1998 |
| 3114 | Monroe Well Service-Ajk | | Oil Operator | Dec 1988 |
| 3115 | Monroe Well Service-Apk | | Oil Operator | Dec 1988 |
| 3116 | Monroe Well Service-Beaver1985 | | Oil Operator | Nov 1991 |
| 3117 | Monroe Well Service-Broadway | | Oil Operator | Dec 1988 |
| 3118 | Monroe Well Service-BWK | | Oil Operator | Dec 1988 |
| 3119 | Monroe Well Service-Columbus | | Oil Operator | Dec 1988 |
| 3120 | Monroe Well Service-Das | | Oil Operator | Mar 1989 |
| 3121 | Monroe Well Service-Derrick | | Oil Operator | Dec 1988 |
| 3122 | Monroe Well Service-East End | | Oil Operator | Dec 1988 |
| 3123 | Monroe Well Service-Empire | | Oil Operator | Dec 1988 |
| 3124 | Monroe Well Service-Energy | | Oil Operator | Dec 1988 |
| 3125 | Monroe Well Service-Energy 84 | | Oil Operator | Aug 1989 |
| 3126 | Monroe Well Service-Ged | | Oil Operator | Dec 1988 |
| 3127 | Monroe Well Service-Gotham | | Oil Operator | Apr 1992 |
| 3128 | Monroe Well Service-Gramercy | | Oil Operator | May 1992 |
| 3129 | Monroe Well Service-HGC | | Oil Operator | Dec 1988 |
| 3130 | Monroe Well Service-Lebo | | Oil Operator | Jun 1989 |
| 3131 | Monroe Well Service-Lexington | | Oil Operator | Feb 1989 |
| 3132 | Monroe Well Service-Newtown | | Oil Operator | Aug 1990 |
| 3133 | Monroe Well Service-Ocean | | Oil Operator | Feb 1989 |
| 3134 | Monroe Well Service-Oceanyacht | | Oil Operator | Jan 1989 |
| 3135 | Monroe Well Service-Oil City | | Oil Operator | Aug 1992 |
| 3136 | Monroe Well Service-Omega | | Oil Operator | Aug 1992 |
| 3137 | Monroe Well Service-Par | | Oil Operator | Jan 1990 |
| 3138 | Monroe Well Service-Petrol | | Oil Operator | Sep 1992 |
| 3139 | Monroe Well Service-Petrovest | | Oil Operator | Dec 1988 |
| 3140 | Monroe Well Service-PRG | | Oil Operator | Nov 1990 |
| 3141 | Monroe Well Service-Redstone | | Oil Operator | Jul 1989 |
| 3142 | Monroe Well Service-RVS | | Oil Operator | Dec 1990 |
| 3143 | Monroe Well Service-Shemen | | Oil Operator | Dec 1988 |
| 3144 | Monroe Well Service-Shemen1984 | | Oil Operator | Jan 1989 |
| 3145 | Monroe Well Service-Shemen1985 | | Oil Operator | Nov 1990 |
| 3146 | Monroe Well Service-Sla | | Oil Operator | Mar 1989 |
| 3147 | Monroe Well Service-SPD | | Oil Operator | Dec 1988 |
| 3148 | Monroe Well Service-SPD 1985 | | Oil Operator | Dec 1988 |
| 3149 | Monroe Well Service-TBR | | Oil Operator | Aug 1991 |
| 3150 | Monroe Well Service-TG I | | Oil Operator | Oct 1990 |
| 3151 | Monroe Well Service-TG II | | Oil Operator | Oct 1990 |
| 3152 | Monroe Well Service-TG III | | Oil Operator | Jul 1992 |
| 3153 | Monroe Well Service-TG VI | | Oil Operator | Aug 1989 |
| 3154 | Monroe Well Service-Tpa 1985 | | Oil Operator | Dec 1990 |
| 3155 | Monroe Well Service-Vista | | Oil Operator | Nov 1990 |
| 3156 | Monroe Well Service-West End | | Oil Operator | Dec 1988 |
| 3157 | Monroe Well Service-York | | Oil Operator | Dec 1988 |
| 3158 | Monsanto Company | Indianapolis, IN 46280 | Oil & Gas Operator | Jan 2005 |
| 3159 | Monsanto Oil Company | | Oil & Gas Operator | Apr 1986 |
| 3160 | Monterey Pipeline Co. | | Oil Operator | Aug 1993 |
| 3161 | Monterey Resources LLC | Dallas, TX 75230 | Oil & Gas Operator | Oct 2019 |
| 3162 | Moon Operating, Inc. | Longview, TX 75601 | Oil & Gas Operator | Mar 2003 |
| 3163 | Moon-Hines-Tigrett Opr Co Inc | | Oil & Gas Operator | Oct 1995 |
| 3164 | Moore McCormack Energy, Inc. | | Oil & Gas Operator | Jul 1988 |
| 3165 | Moore Oil & Gas-Marion Corp. | | Oil & Gas Operator | Nov 1986 |
| 3166 | Moore&Munger Hydrocarbons Inc | | Oil Operator | May 1987 |
| 3167 | Mooringsport Energy Prod Corp | | Oil & Gas Operator | Oct 1994 |
| 3168 | Mooringsport Energy Trans Corp | | Oil Operator | Apr 1990 |
| 3169 | Mor-Co Investments, Inc. | | Gas Operator | Feb 1994 |
| 3170 | Moran Exploration, Inc. | | Oil & Gas Operator | Jan 1985 |
| 3171 | Moran Oil Co., Inc. | | Oil & Gas Operator | Aug 2009 |
| 3172 | Moransco Energy Corporation | Kilgore, TX 75663 | Oil & Gas Operator | Dec 2025 |
| 3173 | Morgan Enterprises | | Oil & Gas Operator | Aug 1997 |
| 3174 | Moro Bay Oil Company, Inc. | | Oil Operator | Jan 1997 |
| 3175 | Mosbacher Energy Company | Houston, TX 77002 | Oil & Gas Operator | Dec 2025 |
| 3176 | Moseley Petroleum Corp. | | Oil & Gas Operator | Apr 1988 |
| 3177 | MRD Operating LLC | | Oil & Gas Operator | Dec 2016 |
| 3178 | Mrs. C. M. Roberson | | Oil Operator | Mar 1989 |
| 3179 | Mrs. Cecile Andries & Sons | | Oil Operator | Dec 2006 |
| 3180 | Mrs. Clara B. Guthrie | | Gas Operator | Jun 1996 |
| 3181 | MRT Exploration Co | | Oil & Gas Operator | Feb 1983 |
| 3182 | MTBB Acquisition Company, LLC | Houston, TX 77002 | Oil & Gas Operator | Aug 2022 |
| 3183 | Mullen Exploration Inc | | Oil & Gas Operator | Dec 2002 |
| 3184 | Mullins & Prichard | | Oil & Gas Operator | May 1992 |
| 3185 | Munday Operating Co., L.L.C. | | Oil & Gas Operator | May 2007 |
| 3186 | Munoco Company | El Dorado, AR 71730 | Oil & Gas Operator | Jul 2021 |
| 3187 | Murchison Oil & Gas Inc | Plano, TX 75024 | Oil & Gas Operator | Aug 2020 |
| 3188 | Murexco Petroleum Inc | Dallas, TX 75251 | Oil & Gas Operator | Oct 1996 |
| 3189 | Murphrey Oil Company, Inc. | | Oil Operator | Jan 2025 |
| 3190 | Murphy - Sun | | Oil & Gas Operator | May 1989 |
| 3191 | Murphy Exp & Prod Co.-USA | | Oil & Gas Operator | May 2014 |
| 3192 | Murphy Exploration & Prod. Co. | Houston, TX 77094 | Oil & Gas Operator | Jun 2011 |
| 3193 | Murphy Oil USA, Inc. | New Orleans, LA 70161 | Oil & Gas Operator | Jan 1993 |
| 3194 | Murray J. Evans | | Oil Operator | Mar 1985 |
| 3195 | Muslow And Parker | | Oil & Gas Operator | Jul 1994 |
| 3196 | Muslow Oil Industries | | Oil Operator | Jan 1995 |
| 3197 | Mustang Energy Inc. | Porter, TX 77365 | Oil & Gas Operator | Mar 2008 |
| 3198 | Mustang Energy L C | | Oil & Gas Operator | Jan 2013 |
| 3199 | MVM Resources Louisiana L.L.C. | | Oil & Gas Operator | Jan 2025 |
| 3200 | MVP Production Inc. | | Oil & Gas Operator | Apr 2005 |