| 21101 | Oryx Energy Company | Dallas, TX 75221 | Oil & Gas Operator | May 2002 |
| 21102 | Os&S Operating Inc. | Electra, TX 76360 | Oil & Gas Operator | Nov 2024 |
| 21103 | Osa Oil & Gas LLC | Tulsa, OK 74131 | Oil & Gas Operator | Aug 2023 |
| 21104 | Osage Energy LLC | Colony, KS 66015 | Oil Operator | Nov 2023 |
| 21105 | Osage Energy Resources LLC | Bartlesville, OK 74005-2527 | Oil & Gas Operator | Sep 2024 |
| 21106 | Osage Exploration & Development Inc | San Diego, CA 92131-3807 | Oil & Gas Operator | Oct 2016 |
| 21107 | Osage Hot Oil Service | Newcastle, WY 82701 | Oil & Gas Operator | Jul 1997 |
| 21108 | Osage Oil & Transportation Inc | Cleveland, OK 74020 | Oil & Gas Operator | Nov 2000 |
| 21109 | Osage Operating | Virginia Beach, VA 23452 | Oil & Gas Operator | Oct 2003 |
| 21110 | Osage Operating Company LLC | Seattle, WA 98133 | Oil Operator | May 2006 |
| 21111 | Osage Partners LLC | | Oil & Gas Operator | Sep 2024 |
| 21112 | Osage Petroleum Corporation | Saint Louis, MO 63131-4691 | Oil & Gas Operator | Mar 2009 |
| 21113 | Osage Resources, LLC | Wichita, KS 67202 | Oil & Gas Operator | Mar 2024 |
| 21114 | Osair Inc | Mentor, OH 44061 | Oil & Gas Operator | Dec 2021 |
| 21115 | Osborn Energy, L.L.C. | Bucyrus, KS 66013 | Oil & Gas Operator | Jul 2017 |
| 21116 | Osborn Heirs Co | San Antonio, TX 78217 | Oil & Gas Operator | Sep 2024 |
| 21117 | Osborn Heirs Com | | Oil & Gas Operator | May 1995 |
| 21118 | Osborn Heirs Company LTD | San Antonio, TX 78217 | Oil & Gas Operator | Jul 2024 |
| 21119 | Osborn Oil & Gas | | Oil & Gas Operator | Jun 1991 |
| 21120 | Osborn,W.B. Oil & Gas Operations | San Antonio, TX 78217 | Oil & Gas Operator | Nov 2024 |
| 21121 | Osborne Oil Co. | Dallas, TX 75244 | Oil & Gas Operator | Aug 2003 |
| 21122 | Osburn Gerald Dba Ozzy & Son Oil & Gas | Drumright, OK 74030-5467 | Oil Operator | Oct 2020 |
| 21123 | Oscar Oil Company | Iowa Park, TX 76367 | Oil & Gas Operator | Sep 2004 |
| 21124 | Oscar'S Well Service Inc | Okemah, OK 74859 | Oil & Gas Operator | Apr 1998 |
| 21125 | Osceola Oil & Gas Corporation | Somerset, TX 78069 | Oil & Gas Operator | Aug 1994 |
| 21126 | Osci Oil And Gas, Inc. | Parker, KS 66072 | Oil Operator | Jun 1998 |
| 21127 | Oshtah Oil Company LLC | Stratford, OK 74872 | Oil & Gas Operator | Sep 2018 |
| 21128 | Oso Exploration & Production, LLC | Houston, TX 77269 | Oil Operator | Nov 2024 |
| 21129 | Oso Exploration Co. | San Antonio, TX 78217 | Oil & Gas Operator | Jul 2011 |
| 21130 | Oso Oil & Gas Properties LLC | Price, UT 84501 | Gas Operator | Jun 2016 |
| 21131 | Oso Resources LLC | Oklahoma City, OK 73118-5022 | Oil & Gas Operator | Aug 2024 |
| 21132 | Ososki Edward D Dba Federal Oil Company | | Oil & Gas Operator | Jun 2022 |
| 21133 | Osprey Petroleum Company, Inc. | Manvel, TX 77578 | Oil & Gas Operator | May 2020 |
| 21134 | Osr Oil & Gas Company | Victoria, TX 77902 | Oil & Gas Operator | Jul 2000 |
| 21135 | Osr Oil & Gas Corp | Midland, TX 79710 | Oil & Gas Operator | Jun 2024 |
| 21136 | Osterhout Phillip L | Drumright, OK 74030-0693 | Oil & Gas Operator | Jan 2014 |
| 21137 | Ostrich Oil & Gas, LLC | Midland, TX 79701 | Oil & Gas Operator | Nov 2024 |
| 21138 | Oswego Arbuckle Enterprise Inc | S Coffeyville, OK 74072-9702 | Oil & Gas Operator | Mar 2015 |
| 21139 | Oswego Oil & Gas | | Oil & Gas Operator | Jun 1984 |
| 21140 | Oswego, Inc. | Amarillo, TX 79109 | Oil & Gas Operator | Jun 2004 |
| 21141 | Osyka Oil & Gas, Inc. | Metairie, LA 70004 | Oil & Gas Operator | Nov 2024 |
| 21142 | Osyka Permian, LLC | Houston, TX 77079 | Oil & Gas Operator | Nov 2024 |
| 21143 | Osyka Producing Company, Inc. | Houston, TX 77242 | Oil & Gas Operator | Nov 2024 |
| 21144 | Otb Operating, LLC | Stanton, TX 79782 | Oil & Gas Operator | Nov 2024 |
| 21145 | Otc Investors Inc | Locust Grove, OK 74352 | Oil Operator | Jul 2024 |
| 21146 | Otc Petroleum Corporation | Nichols Hill, OK 73116 | Oil & Gas Operator | Mar 2015 |
| 21147 | Otc/Occ Not Assigned | | Oil & Gas Operator | May 2024 |
| 21148 | Otex Inc | N Canton, OH 44720 | Oil & Gas Operator | Dec 1988 |
| 21149 | Otex LLC | Santa Anna, TX 76878 | Oil & Gas Operator | Nov 2024 |
| 21150 | Otex Resources LLC | Baytown, TX 77520 | Oil & Gas Operator | Nov 2024 |
| 21151 | Otis C. Coles, Jr. | | Oil & Gas Operator | Jan 1998 |
| 21152 | Oto, Co. | Woodward, OK 73802 | Oil & Gas Operator | Jun 1998 |
| 21153 | Ott Inc | Casper, WY 82602 | Oil Operator | Sep 2024 |
| 21154 | Otter Exploration Inc | Warren, PA 16365-9689 | Oil & Gas Operator | Dec 2021 |
| 21155 | Ouachita Exploration Inc | Chickasha, OK 73018 | Oil & Gas Operator | Sep 2024 |
| 21156 | Ouida Oil | Rowlett, TX 75030 | Oil & Gas Operator | Mar 2008 |
| 21157 | Ouida Oil Co. | | Oil & Gas Operator | Apr 1999 |
| 21158 | Outback Petroleum Inc | Moore, OK 73160-9998 | Oil & Gas Operator | Mar 2015 |
| 21159 | Outlaw Oil And Gas LLC | Kaw City, OK 74641 | Oil & Gas Operator | Aug 2024 |
| 21160 | Outlaw Oil LLC | Caldwell, TX 77836 | Oil & Gas Operator | Nov 2024 |
| 21161 | Outlaw Well Service LLC | Hays, KS 67601 | Oil Operator | Apr 2024 |
| 21162 | Outline Oil Company LLC | Beeville, TX 78104 | Oil Operator | Nov 2024 |
| 21163 | Outline Oil Corp. | San Antonio, TX 78217 | Oil & Gas Operator | Nov 2024 |
| 21164 | Outlook Petroleum Corp. | Midland, TX 79702 | Oil & Gas Operator | Jan 2001 |
| 21165 | Outman, Joshua J. | Andover, NY 14806 | Oil & Gas Operator | Dec 2023 |
| 21166 | Output Acquisition Corp. | | Oil & Gas Operator | Jul 2010 |
| 21167 | Output Exploration LLC | | Oil & Gas Operator | Dec 2006 |
| 21168 | Ouut Investing LLC | Mineral Wells, TX 76068 | Oil Operator | Mar 2020 |
| 21169 | Ovaco Energy Inc. | | Oil & Gas Operator | Nov 2009 |
| 21170 | Ovation Energy II, LP | Houston, TX 77279 | Oil & Gas Operator | Jun 2011 |
| 21171 | Ovation Energy, LP | N Richlnd HLS, TX 76180 | Oil & Gas Operator | Sep 2004 |
| 21172 | Overfield, Lee R | Waverly, KY 42462 | Oil Operator | Dec 2016 |
| 21173 | Overflow Energy Stack LLC | Booker, TX 79005 | Oil Operator | Sep 2022 |
| 21174 | Overflow Energy, LLC | Booker, TX 79005 | Oil & Gas Operator | Nov 2024 |
| 21175 | Overland Exploration Company | | Oil Operator | May 2024 |
| 21176 | Overland Investments Inc | Coweta, OK 74429 | Oil & Gas Operator | Aug 2024 |
| 21177 | Overland Operating Company, LLC | Abilene, TX 79601 | Oil Operator | Nov 2024 |
| 21178 | Overland Resources LLC | Greenwood VIllage, CO 80111 | Oil & Gas Operator | Jul 2019 |
| 21179 | Overly Operating Co. | San Antonio, TX 78209 | Oil & Gas Operator | Jul 2013 |
| 21180 | Overstreet, Jamie L | Hondo, TX 78861 | Oil & Gas Operator | Nov 2024 |
| 21181 | Overton Park Oil & Gas LP | Fort Worth, TX 76109 | Oil & Gas Operator | Nov 2024 |
| 21182 | Ovintiv Mid-Continent Inc. | The Woodlands, TX 77380-2764 | Oil & Gas Operator | Sep 2024 |
| 21183 | Ovintiv USA Inc. | Denver, CO 80202 | Oil & Gas Operator | Nov 2024 |
| 21184 | Owco Production Co., Inc. | | Oil Operator | Aug 1997 |
| 21185 | Owen Contracting Company Inc | | Oil Operator | Apr 2007 |
| 21186 | Owen Production Co | | Oil Operator | May 2001 |
| 21187 | Owen'S Pumping Service | | Oil Operator | Jul 2024 |
| 21188 | Owen, Matthew | Hamilton, KS 66853 | Oil Operator | Sep 2016 |
| 21189 | Owens James W | Tulsa, OK 74114-1425 | Oil & Gas Operator | Oct 2022 |
| 21190 | Owens Oil | | Oil Operator | Dec 2000 |
| 21191 | Owens Oil Company | Iowa Park, TX 76367 | Oil & Gas Operator | Sep 2008 |
| 21192 | Owens Oil Company, LLC | Yates Center, KS 66783 | Oil Operator | Jul 2024 |
| 21193 | Owens Pet Inc | Midland, TX 79702 | Oil & Gas Operator | Aug 1995 |
| 21194 | Owens Petroleum | | Oil Operator | May 2006 |
| 21195 | Owens Petroleum LLC | Yates Center, KS 66783 | Oil & Gas Operator | Jul 2024 |
| 21196 | Owens Petroleum, Inc. | Midland, TX 79702 | Oil & Gas Operator | Aug 1995 |
| 21197 | Owens, Don | | Oil Operator | Oct 2006 |
| 21198 | Owens, Rickey | Windsor, KY 42565 | Oil Operator | Dec 2022 |
| 21199 | Owi Operating Co. LC | Ottawa, KS 66067 | Oil & Gas Operator | Dec 2009 |
| 21200 | Owl Creek Operating Co., Inc. | Denver, CO 80206 | Oil & Gas Operator | Nov 2024 |