| 1 | H & S Oil Company | Kellyville, OK 74039 | Oil & Gas Operator | Mar 1998 |
| 2 | Hailey Energy Corporation | Wesson, MS 39191 | Gas Operator | May 2013 |
| 3 | Halliburton Oil Producing Co. | Duncan, OK 73534 | Oil & Gas Operator | Apr 2016 |
| 4 | Hamp Oil | Ponca City, OK 74604 | Oil & Gas Operator | Sep 2002 |
| 5 | Harrison Oil & Gas Inc | Houston, TX 77019 | Oil & Gas Operator | Jun 2025 |
| 6 | Hazlewood Oil & Gas Co Inc | Oklahoma City, OK 73139-9353 | Oil & Gas Operator | Apr 2022 |
| 7 | HCG Energy Corporation & Subs | | Oil & Gas Operator | Mar 2015 |
| 8 | Headington Oil Company | Dallas, TX 75231 | Oil & Gas Operator | Dec 2016 |
| 9 | Henson Terry Dba Daycon Exploration | Tulsa, OK 74137-3546 | Oil & Gas Operator | Jun 2025 |
| 10 | Hiawatha Exploration Company | Oklahoma City, OK 73116-7326 | Oil & Gas Operator | Mar 2009 |
| 11 | Hitchita #1 LP | Edmond, OK 73013-6628 | Oil & Gas Operator | Sep 1997 |
| 12 | Holke Dave Consulting Inc | Meridian, ID 83646-4812 | Oil & Gas Operator | Jun 2025 |
| 13 | Horizon Natural Resources, Inc. | Tulsa, OK 74136 | Oil & Gas Operator | Jan 2019 |
| 14 | HRB Operating Company, Inc. | Bridgeport, TX 76426 | Oil & Gas Operator | Oct 2025 |
| 15 | HRC Production Co | Houston, TX 77024 | Oil & Gas Operator | May 2025 |
| 16 | Hunt Engineering Inc | Norman, OK 73069-4093 | Oil & Gas Operator | Feb 2019 |
| 17 | Hutton Gas Operating Company | Tulsa, OK 74136 | Oil & Gas Operator | Mar 2015 |