| 8101 | Old Chief Oil, LLC | New Braunfels, TX 78132 | Oil Operator | Feb 2026 |
| 8102 | Old Pine Energy Corporation | Austin, TX 78755 | Oil Operator | Feb 2026 |
| 8103 | Old Timers Oil | Saratoga, TX 77585 | Oil & Gas Operator | Nov 2014 |
| 8104 | Old Timers Oil Company, LLC | Saratoga, TX 77585 | Oil Operator | Aug 2022 |
| 8105 | Old Timers Oil No. 2 Incorporated | Saratoga, TX 77585 | Oil Operator | Feb 2026 |
| 8106 | Old Union Operating Company | Austin, TX 78716 | Oil & Gas Operator | Feb 2026 |
| 8107 | Older Than Dirt LLC | Weatherford, TX 76086 | Oil & Gas Operator | Feb 2026 |
| 8108 | Oldfield Acquisition LP | Austin, TX 78733 | Oil & Gas Operator | Sep 1996 |
| 8109 | Ole Chaparral On Possum Kingdom | Wichita Falls, TX 76307 | Oil & Gas Operator | Dec 1997 |
| 8110 | Ole, Inc. | Graham, TX 76450 | Oil & Gas Operator | Aug 2003 |
| 8111 | Olenox Corp. | Katy, TX 77449 | Oil Operator | Feb 2026 |
| 8112 | Oleum Exploration, LLC | Brodheadsvill, PA 18322 | Oil & Gas Operator | Mar 2023 |
| 8113 | Oleum Operating Company, L.C. | Longview, TX 75606 | Oil & Gas Operator | Dec 2021 |
| 8114 | Oleum Partners, LLC | Frisco, TX 75034 | Oil & Gas Operator | Feb 2026 |
| 8115 | Olifant Energy LLC | Tulsa, OK 74119 | Oil & Gas Operator | Jun 2019 |
| 8116 | Olipdp II, LLC | Lafayette, LA 70503 | Oil & Gas Operator | Feb 2026 |
| 8117 | Oliver Oil & Gas | Midland, TX 79702 | Oil & Gas Operator | Feb 2026 |
| 8118 | Olmos Partners, Inc. | Boerne, TX 78006 | Oil & Gas Operator | Feb 2026 |
| 8119 | Olney Oil LLC | Boerne, TX 78006 | Oil Operator | Feb 2026 |
| 8120 | Olney Properties, Inc. | Wichita Falls, TX 76307 | Oil & Gas Operator | Sep 2003 |
| 8121 | Olsan Brothers, Inc. | Dallas, TX 75251 | Oil & Gas Operator | Apr 1994 |
| 8122 | Olsen Energy Inc. | Boerne, TX 78006 | Oil & Gas Operator | Feb 2026 |
| 8123 | Olson, Gary P. P.E. | Granbury, TX 76048 | Oil & Gas Operator | Feb 2026 |
| 8124 | Olson, S. A. | Kenedy, TX 78119 | Oil & Gas Operator | Aug 1994 |
| 8125 | Oltex Production | Idalou, TX 79329 | Oil & Gas Operator | Feb 2026 |
| 8126 | Omar Operating Company | Midland, TX 79702 | Oil & Gas Operator | Sep 2013 |
| 8127 | Omber Petroleum & Energy Corp. | New Braunfels, TX 78131 | Oil & Gas Operator | Feb 2026 |
| 8128 | Omega Alpha Resources, LLC | Dallas, TX 75219 | Oil Operator | Feb 2026 |
| 8129 | Omega Energy Corp. | Graham, TX 76450 | Oil & Gas Operator | Feb 2026 |
| 8130 | Omega Energy, LLC | Corpus Chrsti, TX 78418 | Oil & Gas Operator | Feb 2026 |
| 8131 | Omega Operating, Inc. | Odessa, TX 79769 | Oil & Gas Operator | Mar 2001 |
| 8132 | Omimex Energy, Inc. | Fort Worth, TX 76120 | Oil & Gas Operator | Oct 2025 |
| 8133 | Omimex Petroleum Inc | Fort Worth, TX 76120 | Oil & Gas Operator | Aug 2022 |
| 8134 | Omni E & P, Inc. | San Antonio, TX 78229 | Oil Operator | Apr 2010 |
| 8135 | Omni Oil & Gas, Inc. | San Antonio, TX 78229 | Oil & Gas Operator | Oct 2017 |
| 8136 | Omni Operating Company(A) | Dallas, TX 75370 | Oil & Gas Operator | Feb 2026 |
| 8137 | Omni Petroleum Corporation | Austin, TX 78738 | Oil & Gas Operator | Feb 2026 |
| 8138 | Omta Operating LLC | Corpus Chrsti, TX 78418 | Oil & Gas Operator | Feb 2026 |
| 8139 | On Pointe Operating LLC | Jones, OK 73049 | Oil & Gas Operator | Feb 2026 |
| 8140 | Onaroll Operating LLC | Levelland, TX 79336 | Oil Operator | Feb 2026 |
| 8141 | One Epoch Energy, Inc. | Abilene, TX 79604 | Oil & Gas Operator | Mar 2008 |
| 8142 | One Nickel Operating LLC | Ashland, MA 01721 | Oil Operator | Feb 2026 |
| 8143 | One Tec Operating, LLC | Houston, TX 77002 | Oil & Gas Operator | Nov 2007 |
| 8144 | One World Operating, LLC | Tampa, FL 33602 | Oil & Gas Operator | Feb 2026 |
| 8145 | Oneok Exploration Company | Tulsa, OK 74102 | Oil & Gas Operator | Feb 2017 |
| 8146 | Oneok Resources Company | Tulsa, OK 74102 | Oil & Gas Operator | Feb 2017 |
| 8147 | Onshore Royalties LLC | Houston, TX 77269 | Oil & Gas Operator | Dec 2025 |
| 8148 | Onyx Industries LTD, Inc. | Wichita Falls, TX 76308 | Oil & Gas Operator | Aug 2003 |
| 8149 | Onyx Producing Company, Inc. | Pampa, TX 79066 | Oil & Gas Operator | Mar 2008 |
| 8150 | Opal Energy, Inc. | Katy, TX 77494 | Oil & Gas Operator | Jun 2009 |
| 8151 | Opal Operating Company LLC | Edmond, OK 73013 | Oil & Gas Operator | Feb 2026 |
| 8152 | Opal Resources Operating Co.,LLC | Cypress, TX 77429 | Oil & Gas Operator | Jan 2019 |
| 8153 | Opco Oil & Gas Co. | Dallas, TX 75231 | Oil & Gas Operator | Aug 2003 |
| 8154 | Opex Energy, LLC | Houston, TX 77042 | Oil & Gas Operator | Mar 2008 |
| 8155 | Opmi Operating Company | Houston, TX 77057 | Oil & Gas Operator | Jun 2008 |
| 8156 | Ops Group Limited | Houston, TX 77060 | Oil & Gas Operator | Jun 2014 |
| 8157 | Optimum Exploration LLC | Dallas, TX 75254 | Oil & Gas Operator | Feb 2026 |
| 8158 | Orange Petroleum Co. | Orangefield, TX 77639 | Oil & Gas Operator | May 1995 |
| 8159 | Orangefield Operating Corporation | Dallas, TX 75382 | Oil Operator | Feb 2026 |
| 8160 | Orbis Energy, L.L.C. | Austin, TX 78746 | Oil & Gas Operator | Oct 2001 |
| 8161 | Orbit Crude, Inc. | Midland, TX 79710 | Oil & Gas Operator | Feb 2026 |
| 8162 | Orbit Enterprises, Inc. | Lovington, NM 88260 | Oil & Gas Operator | Mar 2015 |
| 8163 | Orbitron Operating Corp. | Fort Worth, TX 76102 | Oil & Gas Operator | Dec 1995 |
| 8164 | Orca Operating Company LLC | Houston, TX 77056 | Oil & Gas Operator | Dec 2025 |
| 8165 | Oretta Holdings LLC | Houston, TX 77010 | Oil & Gas Operator | Feb 2026 |
| 8166 | Orgain, John C. | Graham, TX 76450 | Oil & Gas Operator | Jul 1997 |
| 8167 | Origin Prod Co Gonzales Prop LLC | New Braunfels, TX 78132 | Oil & Gas Operator | Feb 2026 |
| 8168 | Origin Production Company, Inc. | New Braunfels, TX 78132 | Oil & Gas Operator | Feb 2026 |
| 8169 | Origin Production Group LLC | Luling, TX 78648 | Oil Operator | Feb 2026 |
| 8170 | Oringderff, Alma Oil Properties | Dallas, TX 75225 | Oil & Gas Operator | Mar 2012 |
| 8171 | Oriole Operating LLC | Wichita Falls, TX 76308 | Oil Operator | Feb 2026 |
| 8172 | Orion Energen Inc. | Austin, TX 78731 | Oil & Gas Operator | Jul 2023 |
| 8173 | Orion Oil & Gas Properties | Amarillo, TX 79109 | Gas Operator | Oct 2000 |
| 8174 | Orion Oil & Gas, LLC | Houston, TX 77042 | Oil & Gas Operator | Oct 2007 |
| 8175 | Orion Oil And Gas Corporation | Houston, TX 77082 | Oil & Gas Operator | Feb 2026 |
| 8176 | Orion Resources, Inc. | San Antonio, TX 78209 | Oil & Gas Operator | Feb 2026 |
| 8177 | Orisol Oil Co. | Houston, TX 77206 | Oil Operator | Jun 2000 |
| 8178 | Orla Petco, Inc. | Midland, TX 79708 | Oil & Gas Operator | Feb 2026 |
| 8179 | Orland Oil & Gas LLC | FT Lauderdale, FL 33305 | Oil Operator | Aug 2024 |
| 8180 | Ormand, Don R. | Midland, TX 79705 | Oil & Gas Operator | Jan 2016 |
| 8181 | Oro Resources, LLC | Houston, TX 77024 | Oil & Gas Operator | Feb 2026 |
| 8182 | Orphan Wells, LLC | Palmhurst, TX 78573 | Oil & Gas Operator | Feb 2026 |
| 8183 | Orr Production Company | Austin, TX 78746 | Oil & Gas Operator | Dec 2000 |
| 8184 | Orr, Robert M. | Monahans, TX 79756 | Oil & Gas Operator | Oct 1998 |
| 8185 | Orsburn, Wade Inc. | Gainesville, TX 76240 | Oil & Gas Operator | Nov 2002 |
| 8186 | Orson Leasing & Supply | Rockdale, TX 76567 | Oil & Gas Operator | Dec 2006 |
| 8187 | Orth Oil Company, Inc. | Cisco, TX 76437 | Oil & Gas Operator | Feb 2026 |
| 8188 | Orx Resources, L.L.C. | Houston, TX 77067 | Oil & Gas Operator | Feb 2026 |
| 8189 | Oryx Energy Company | Dallas, TX 75221 | Oil & Gas Operator | May 2002 |
| 8190 | Os&S Operating Inc. | Electra, TX 76360 | Oil & Gas Operator | Feb 2026 |
| 8191 | Osborn Heirs Co | San Antonio, TX 78217 | Oil & Gas Operator | Dec 2025 |
| 8192 | Osborn,W.B. Oil & Gas Operations | San Antonio, TX 78217 | Oil & Gas Operator | Feb 2026 |
| 8193 | Osborne Oil Co. | Dallas, TX 75244 | Oil & Gas Operator | Aug 2003 |
| 8194 | Oscar Oil Company | Iowa Park, TX 76367 | Oil & Gas Operator | Sep 2004 |
| 8195 | Osceola Oil & Gas Corporation | Somerset, TX 78069 | Oil & Gas Operator | Aug 1994 |
| 8196 | Oso Energy Company | Houston, TX 77280 | Oil & Gas Operator | Feb 1997 |
| 8197 | Oso Exploration & Production, LLC | Houston, TX 77269 | Oil Operator | Feb 2026 |
| 8198 | Oso Exploration Co. | San Antonio, TX 78217 | Oil & Gas Operator | Jul 2011 |
| 8199 | Osprey Petroleum Company, Inc. | Manvel, TX 77578 | Oil & Gas Operator | May 2020 |
| 8200 | Osr Oil & Gas Company | Victoria, TX 77902 | Oil & Gas Operator | Jul 2000 |