| 1 | Hanna Oil And Gas Company | Fort Smith, AR 72901 | Oil & Gas Operator | Feb 2025 |
| 2 | Harwood Oil & Gas Inc | Greeley, CO 80631-8233 | Oil & Gas Operator | Feb 2025 |
| 3 | Hawkins Oil & Gas Inc | Tulsa, OK 74103 | Oil & Gas Operator | Dec 2016 |
| 4 | HCG Energy Corporation & Subs | | Oil & Gas Operator | Mar 2015 |
| 5 | Headington Oil Company | Dallas, TX 75231 | Oil & Gas Operator | Dec 2016 |
| 6 | Headington Oil Company LLC | Dallas, TX 75204 | Oil & Gas Operator | Apr 2016 |
| 7 | Helmerich & Payne, Inc. | Tulsa, OK 74114 | Oil & Gas Operator | Feb 2025 |
| 8 | Henderson Charles E | Bokoshe, OK 74930 | Gas Operator | Oct 2021 |
| 9 | Henry Petroleum Of Oklahoma LP | Midland, TX 79703-5000 | Oil & Gas Operator | Feb 2017 |
| 10 | Hess Corporation | Houston, TX 77010 | Oil & Gas Operator | Aug 2017 |
| 11 | Heston Oil Company | Tulsa, OK 74108 | Oil & Gas Operator | Mar 2005 |
| 12 | Highland Oil & Gas LLC | Houston, TX 77079-7220 | Oil & Gas Operator | Feb 2015 |
| 13 | HK Energy Operating, LLC | Houston, TX 77002 | Oil & Gas Operator | May 2023 |
| 14 | Hoover & Wilson Exp & Prod Inc | Fort Smith, AR 72913-5171 | Gas Operator | Jul 2013 |
| 15 | Horizon Natural Gas Company | Tulsa, OK 74170 | Oil & Gas Operator | Oct 2024 |
| 16 | Horizon Natural Resources, Inc. | Tulsa, OK 74136 | Oil & Gas Operator | Jan 2019 |
| 17 | HRC Production Co | Houston, TX 77024 | Oil & Gas Operator | Jan 2025 |
| 18 | Hulen Operating Company | Nichols Hill, OK 73116 | Oil & Gas Operator | Jun 2025 |
| 19 | Hunt Oil Company | Dallas, TX 75201 | Oil & Gas Operator | Jun 2025 |