| 4101 | Oil Pool Inc | Tulsa, OK 74132-2659 | Oil & Gas Operator | Jan 2026 |
| 4102 | Oil Producers, Inc. Of Kansas | Wichita, KS 67206 | Oil & Gas Operator | May 2026 |
| 4103 | Oil Production Management Inc | Squaw Valley, CA 93675-9725 | Oil & Gas Operator | Dec 2002 |
| 4104 | Oil Production Systems Inc | Cushing, OK 74023 | Oil & Gas Operator | Jan 2013 |
| 4105 | Oil Property Management Inc | Attica, KS 67009 | Oil & Gas Operator | Feb 2021 |
| 4106 | Oil Recovery Systems Inc | Tulsa, OK 74145-4619 | Oil & Gas Operator | Jan 2026 |
| 4107 | Oil State Petroleum Inc | Jennings, OK 74038 | Oil & Gas Operator | Feb 2026 |
| 4108 | Oil Ventures LTD | | Oil & Gas Operator | Jan 2013 |
| 4109 | Oilbank Production LLC | Norman, OK 73072 | Oil Operator | Jan 2026 |
| 4110 | Oilco Energy Inc | Duncan, OK 73533 | Oil & Gas Operator | Mar 2015 |
| 4111 | Oilfield Operating Company | Cushing, OK 74023-1347 | Oil & Gas Operator | Jan 2018 |
| 4112 | Oilrox Resources LLC | San Antonio, TX 78258 | Oil & Gas Operator | Feb 2026 |
| 4113 | Oilsearch Corporation | Albuquerque, NM 87109 | Oil & Gas Operator | Feb 1994 |
| 4114 | Oilton Petroleum Inc | Oilton, OK 74052-0459 | Oil & Gas Operator | Oct 2001 |
| 4115 | Oilwell Operators, Inc. | Pampa, TX 79066 | Oil & Gas Operator | May 2026 |
| 4116 | Ok Production Services Inc | Broken Arrow, OK 74014 | Oil & Gas Operator | Feb 2026 |
| 4117 | Okc Energy Corporation | Oklahoma City, OK 73120-3119 | Oil & Gas Operator | Nov 2014 |
| 4118 | Okie Crude Company | Tulsa, OK 74103 | Oil & Gas Operator | Jan 2026 |
| 4119 | Okie Oil Inc | Sapulpa, OK 74067-0290 | Oil & Gas Operator | Mar 2011 |
| 4120 | Okla Sub-Surface Pump & Supply Co | Ada, OK 74820 | Oil & Gas Operator | Sep 2024 |
| 4121 | Oklahoma Basic Economy Corp | Houston, TX 77002-6003 | Oil & Gas Operator | Apr 2020 |
| 4122 | Oklahoma Cellulose Inc | Cleveland, OK 74020 | Oil Operator | Feb 2026 |
| 4123 | Oklahoma Crude Inc | Morris, OK 74445 | Oil & Gas Operator | Nov 2025 |
| 4124 | Oklahoma Crude Reclaimers, LLC | | Oil Operator | Feb 2026 |
| 4125 | Oklahoma Energy Acquisitions LP | Houston, TX 77094-1900 | Oil & Gas Operator | Feb 2026 |
| 4126 | Oklahoma Energy Exchange LLC | Duncan, OK 73534-1105 | Oil & Gas Operator | Sep 2012 |
| 4127 | Oklahoma Energy LLC | Skiatook, OK 74070-3998 | Oil Operator | Apr 2025 |
| 4128 | Oklahoma Equipment & Salvage | Oklahoma City, OK 73120-5903 | Oil & Gas Operator | Mar 2015 |
| 4129 | Oklahoma Gas & Oil Corp | | Oil Operator | Oct 2018 |
| 4130 | Oklahoma Liquid Resources Inc | Collinsville, OK 74021 | Oil & Gas Operator | Dec 2025 |
| 4131 | Oklahoma Natural Resources Inc | Woodward, OK 73801 | Oil & Gas Operator | Sep 1996 |
| 4132 | Oklahoma O & G Royalties Inc | Duncan, OK 73533 | Oil & Gas Operator | Nov 2000 |
| 4133 | Oklahoma Oil & Gas MGMT Inc | Edmond, OK 73083-6786 | Oil & Gas Operator | Jan 2026 |
| 4134 | Oklahoma Oil And Gas Resources LLC | Guthrie, OK 73044-8095 | Oil & Gas Operator | Jan 2026 |
| 4135 | Oklahoma Oil Company | Dallas, TX 75206 | Oil & Gas Operator | Aug 2013 |
| 4136 | Oklahoma Oil Tactics Inc | Edmond, OK 73003-1351 | Oil & Gas Operator | Mar 2015 |
| 4137 | Oklahoma Petroleum MGMT Corp | Tulsa, OK 74119 | Oil & Gas Operator | Jun 1993 |
| 4138 | Oklahoma Prime Energy LLC | Ardmore, OK 73401 | Oil Operator | May 2020 |
| 4139 | Oklahoma Rig & Salvage Inc | Oklahoma City, OK 73114 | Oil & Gas Operator | Mar 2015 |
| 4140 | Oklahoma SWD Systems Inc | Odessa, TX 79762-8132 | Oil & Gas Operator | Jan 2026 |
| 4141 | Oklahoma Tank Service Inc | Oklahoma City, OK 73143 | Oil Operator | Aug 1997 |
| 4142 | Okland Oil Company | Oklahoma City, OK 73102-9022 | Oil & Gas Operator | Feb 2026 |
| 4143 | Oklaoleum Oil And Gas Inc | Bristow, OK 74010-0057 | Oil Operator | Jan 2016 |
| 4144 | Okmar Oil Company | Marietta, OH 45750 | Oil & Gas Operator | Jun 2005 |
| 4145 | Okt Petroleum Company Inc | Oklahoma City, OK 73118-7425 | Oil & Gas Operator | Oct 2013 |
| 4146 | Oktex Operating LLC | Edmond, OK 73013-1961 | Oil & Gas Operator | May 2020 |
| 4147 | Oky Investments, Inc. | Edmond, OK 73013 | Oil & Gas Operator | Sep 2021 |
| 4148 | Old Dominion Oil Corporation | Oklahoma City, OK 73107 | Oil & Gas Operator | Apr 2009 |
| 4149 | Ole Crow Operating | Wichita Falls, TX 76308 | Oil Operator | Jan 2026 |
| 4150 | Oleum Inc | | Oil & Gas Operator | Mar 1996 |
| 4151 | Olia Oil & Gas Services LLC | Cedar Park, TX 78630-2049 | Oil & Gas Operator | Aug 2022 |
| 4152 | Oliphant Gertrud | Holdenville, OK 74848-0849 | Oil Operator | Aug 2013 |
| 4153 | Oliphant Operating Co,LTD,LLC | | Oil Operator | Feb 2026 |
| 4154 | Olive Oil & Gas Inc | Jennings, OK 74052 | Oil & Gas Operator | Jan 2026 |
| 4155 | Olympia Oil Inc | Edmond, OK 73083-7088 | Oil & Gas Operator | Jul 2020 |
| 4156 | Olympic Petroleum Co | Tulsa, OK 74114 | Oil & Gas Operator | Jun 1998 |
| 4157 | Omega Energy, LLC | Corpus Christ, TX 78418 | Oil & Gas Operator | May 2026 |
| 4158 | Omimex International Corp | Fort Worth, TX 76103-2300 | Oil & Gas Operator | Jan 2026 |
| 4159 | Omimex Petroleum Inc | Fort Worth, TX 76120 | Oil & Gas Operator | Aug 2022 |
| 4160 | Omni Oil & Gas, Inc. | San Antonio, TX 78229 | Oil & Gas Operator | Oct 2017 |
| 4161 | On-Line Oil Inc | Oklahoma City, OK 73105-5208 | Oil & Gas Operator | Mar 2015 |
| 4162 | Onapa Gas Company LLC | Tulsa, OK 74136-7253 | Gas Operator | Nov 2019 |
| 4163 | Oneok Exploration Company | Tulsa, OK 74102 | Oil & Gas Operator | Feb 2017 |
| 4164 | Oneok Field Services Company | Tulsa, OK 74103 | Oil & Gas Operator | Jan 2026 |
| 4165 | Oneok Gas Processing LLC | Tulsa, OK 74103 | Oil & Gas Operator | May 2018 |
| 4166 | Oneok Gas Transportation Co | Tulsa, OK 74121-2089 | Oil & Gas Operator | Oct 2014 |
| 4167 | Oneok Resources Company | Tulsa, OK 74102 | Oil & Gas Operator | Feb 2017 |
| 4168 | Onpoint Oil & Gas, LLC | Oklahoma City, OK 73170 | Oil & Gas Operator | Jan 2026 |
| 4169 | Onshore Royalties LLC | Houston, TX 77269 | Oil & Gas Operator | Feb 2026 |
| 4170 | Onyx Energy Corporation | Oklahoma City, OK 73157 | Oil & Gas Operator | May 1994 |
| 4171 | Onyx Properties Corp | Oklahoma City, OK 73114 | Oil & Gas Operator | May 2006 |
| 4172 | Opal Operating Company LLC | Edmond, OK 73013 | Oil & Gas Operator | May 2026 |
| 4173 | Open Door Holdings Inc | Surprise, AZ 85387-2015 | Oil & Gas Operator | Feb 2024 |
| 4174 | Open Door Productions Inc | Muskogee, OK 74401-1032 | Oil & Gas Operator | Apr 2020 |
| 4175 | Open Range Energy LLC | Jones, OK 73049-8744 | Oil & Gas Operator | Dec 2024 |
| 4176 | Optima Exploration LLC | Tulsa, OK 74116-5664 | Oil & Gas Operator | Mar 2015 |
| 4177 | Opubco Resources Of TX Inc | Dallas, TX 75231 | Oil & Gas Operator | Sep 2005 |
| 4178 | Oracle Resources Oklahoma LP | Dallas, TX 75240-5751 | Oil & Gas Operator | Feb 2008 |
| 4179 | Orason Resources Inc | Tulsa, OK 74169-1225 | Oil & Gas Operator | Nov 2006 |
| 4180 | Orca Operating Company LLC | Houston, TX 77056 | Oil & Gas Operator | Feb 2026 |
| 4181 | Oren Stone | Erick, OK 73645-4542 | Gas Operator | Jun 2022 |
| 4182 | Orion Exploration LLC | Tulsa, OK 74105-5153 | Oil & Gas Operator | Apr 2015 |
| 4183 | Orion Exploration Partners LLC | Tulsa, OK 74105-5153 | Oil & Gas Operator | Nov 2025 |
| 4184 | Orloski John C | Bartlesville, OK 74006 | Oil & Gas Operator | Jun 2025 |
| 4185 | Osa Oil & Gas LLC | Tulsa, OK 74131 | Oil & Gas Operator | Aug 2023 |
| 4186 | Osage Energy Resources LLC | Bartlesville, OK 74005-2527 | Oil & Gas Operator | Feb 2026 |
| 4187 | Osage Exploration & Development Inc | San Diego, CA 92131-3807 | Oil & Gas Operator | Oct 2016 |
| 4188 | Osage Oil & Transportation Inc | Cleveland, OK 74020 | Oil & Gas Operator | Nov 2000 |
| 4189 | Osage Petroleum Corporation | Saint Louis, MO 63131-4691 | Oil & Gas Operator | Mar 2009 |
| 4190 | Osborn Heirs Co | San Antonio, TX 78217 | Oil & Gas Operator | Mar 2026 |
| 4191 | Osburn Gerald Dba Ozzy & Son Oil & Gas | Drumright, OK 74030-5467 | Oil Operator | Oct 2020 |
| 4192 | Oscar'S Well Service Inc | Okemah, OK 74859 | Oil & Gas Operator | Apr 1998 |
| 4193 | Oshtah Oil Company LLC | Stratford, OK 74872 | Oil & Gas Operator | Sep 2018 |
| 4194 | Oso Resources LLC | Edmond, OK 73003 | Oil & Gas Operator | Jan 2026 |
| 4195 | Osterhout Phillip L | Drumright, OK 74030-0693 | Oil & Gas Operator | Jan 2014 |
| 4196 | Oswego Arbuckle Enterprise Inc | S Coffeyville, OK 74072-9702 | Oil & Gas Operator | Mar 2015 |
| 4197 | Otc Investors Inc | | Oil Operator | Jan 2026 |
| 4198 | Otc Petroleum Corporation | Nichols Hill, OK 73116 | Oil & Gas Operator | Mar 2015 |
| 4199 | Otc/Occ Not Assigned | | Oil & Gas Operator | Dec 2024 |
| 4200 | Ouachita Exploration Inc | Chickasha, OK 73018 | Oil & Gas Operator | Feb 2026 |