| 1 | H & H Operating | Olney, TX 76374 | Oil & Gas Operator | Jun 2025 |
| 2 | H B Oil & Gas Inc | Oklahoma City, OK 73159 | Oil & Gas Operator | Jun 2000 |
| 3 | H.L.S. Energy Co., Inc. | Uvalde, TX 78801 | Oil & Gas Operator | Aug 2003 |
| 4 | Hadson Petro USA Inc | | Oil & Gas Operator | Nov 2016 |
| 5 | Halcon Holdings Inc | Ada, OK 74820 | Oil & Gas Operator | Nov 2018 |
| 6 | Halgas Inc | Tulsa, OK 74101-3012 | Oil & Gas Operator | May 2013 |
| 7 | Halliburton Oil Producing Co. | Duncan, OK 73534 | Oil & Gas Operator | Apr 2016 |
| 8 | Hanoco Inc | Tulsa, OK 74135 | Oil & Gas Operator | Feb 2025 |
| 9 | Harrison-Wright Oil Company LLC | Tulsa, OK 74133-7035 | Oil & Gas Operator | Feb 2025 |
| 10 | Hays Herb E & K S | Bartlesville, OK 74006 | Oil Operator | Feb 2025 |
| 11 | Hays Operating Company | Oklahoma City, OK 73102 | Oil & Gas Operator | Mar 2000 |
| 12 | Hazelwood Prod & Exp Co LLC | Oklahoma City, OK 73116-9037 | Oil & Gas Operator | Jan 2025 |
| 13 | Hazlewood Oil & Gas Co Inc | Oklahoma City, OK 73139-9353 | Oil & Gas Operator | Apr 2022 |
| 14 | Headington Oil Company | Dallas, TX 75231 | Oil & Gas Operator | Dec 2016 |
| 15 | Headington Oil Company LLC | Dallas, TX 75204 | Oil & Gas Operator | Apr 2016 |
| 16 | Helmerich & Payne, Inc. | Tulsa, OK 74114 | Oil & Gas Operator | Feb 2025 |
| 17 | Helton Oil Company | Edmond, OK 73083-7283 | Oil & Gas Operator | Aug 2016 |
| 18 | Henry Petroleum Inc | Oklahoma City, OK 73162-1757 | Oil & Gas Operator | Sep 2019 |
| 19 | Heritage Oil Company | Norman, OK 73070 | Oil & Gas Operator | Jul 2008 |
| 20 | Heritage Petroleum, Inc. | Stillwater, OK 74076 | Oil & Gas Operator | Jun 2025 |
| 21 | Herrmann Arnold | Chandler, OK 74834 | Oil & Gas Operator | Sep 2024 |
| 22 | Hiawatha Exploration Company | Oklahoma City, OK 73116-7326 | Oil & Gas Operator | Mar 2009 |
| 23 | High Energy | Cushing, OK 74023 | Oil & Gas Operator | Feb 2025 |
| 24 | Hightower Energy LLC | Cushing, OK 74023-6370 | Oil & Gas Operator | Mar 2025 |
| 25 | Hill Gilford | Stroud, OK 74079-9401 | Oil & Gas Operator | May 2013 |
| 26 | Hill Oil Company Inc | Shawnee, OK 74804 | Oil & Gas Operator | Feb 2025 |
| 27 | Hill Resources Inc | | Oil & Gas Operator | Nov 2022 |
| 28 | Hills Dozer Service | Stroud, OK 74079 | Oil & Gas Operator | Mar 2022 |
| 29 | Himco Oil & Gas, Inc. | Enid, OK 73702 | Oil & Gas Operator | Feb 2025 |
| 30 | Hinkle Engineering, Inc. | Oklahoma City, OK 73112 | Oil & Gas Operator | Nov 2016 |
| 31 | Hinkle Oil And Gas Inc | Oklahoma City, OK 73112-4275 | Oil & Gas Operator | Mar 2025 |
| 32 | HLH Realty Co | Drumright, OK 74030 | Oil & Gas Operator | Mar 2016 |
| 33 | Hodgden Operating Co., Inc. | Enid, OK 73702 | Oil & Gas Operator | Mar 2025 |
| 34 | Holden Energy Corporation | Ardmore, OK 73401 | Oil & Gas Operator | Mar 2015 |
| 35 | Hondo Oil & Gas Company | Roswell, NM 88202 | Oil & Gas Operator | Aug 2006 |
| 36 | Hoppes Helen E | Depew, OK 74028-3428 | Oil & Gas Operator | Apr 2015 |
| 37 | Horizon Resources Inc | Fort Worth, TX 76101-1978 | Oil & Gas Operator | Jul 2006 |
| 38 | Hovas Enterprises | Perkins, OK 74059 | Oil & Gas Operator | Mar 2014 |
| 39 | Howco Oil And Gas | Stroud, OK 74079-9604 | Oil & Gas Operator | Mar 2015 |
| 40 | Hulen Operating Company | Nichols Hill, OK 73116 | Oil & Gas Operator | Jun 2025 |
| 41 | Huntington Energy LLC | Nichols Hill, OK 73116 | Oil & Gas Operator | Jun 2025 |