| 1 | Halliburton Oil Producing Co. | Duncan, OK 73534 | Oil & Gas Operator | Apr 2016 |
| 2 | Hamp Oil | Ponca City, OK 74604 | Oil & Gas Operator | Sep 2002 |
| 3 | Harrison Oil & Gas Inc | Houston, TX 77019 | Oil & Gas Operator | Dec 2025 |
| 4 | Hazlewood Oil & Gas Co Inc | Oklahoma City, OK 73139-9353 | Oil & Gas Operator | Apr 2022 |
| 5 | HCG Energy Corporation & Subs | | Oil & Gas Operator | Mar 2015 |
| 6 | Headington Oil Company | Dallas, TX 75231 | Oil & Gas Operator | Dec 2016 |
| 7 | Henson Terry Dba Daycon Exploration | Tulsa, OK 74133 | Oil & Gas Operator | Feb 2026 |
| 8 | Hiawatha Exploration Company | Oklahoma City, OK 73116-7326 | Oil & Gas Operator | Mar 2009 |
| 9 | Hitchita #1 LP | Edmond, OK 73013-6628 | Oil & Gas Operator | Sep 1997 |
| 10 | Holke Dave Consulting Inc | Meridian, ID 83646-4812 | Oil & Gas Operator | Feb 2026 |
| 11 | Horizon Natural Resources, Inc. | Tulsa, OK 74136 | Oil & Gas Operator | Jan 2019 |
| 12 | HRB Operating Company, Inc. | Bridgeport, TX 76426 | Oil & Gas Operator | Jun 2026 |
| 13 | HRC Production Co | Houston, TX 77024 | Oil & Gas Operator | Mar 2026 |
| 14 | Hunt Engineering Inc | Norman, OK 73069-4093 | Oil & Gas Operator | Feb 2019 |
| 15 | Hutton Gas Operating Company | Tulsa, OK 74136 | Oil & Gas Operator | Mar 2015 |