| 1 | H & L Operating Co LLP | Amarillo, TX 79114 | Oil & Gas Operator | Aug 2022 |
| 2 | H & L Operating Company | Amarillo, TX 79114 | Oil & Gas Operator | Feb 2020 |
| 3 | H G & G Inc | Edmond, OK 73034 | Oil & Gas Operator | Jan 2006 |
| 4 | Hadaway Consulting And Engineering LLC | Canadian, TX 79014 | Oil & Gas Operator | Jun 2024 |
| 5 | Hadaway Engineering Inc | Canadian, TX 79014 | Oil & Gas Operator | Jul 2015 |
| 6 | Halcon Holdings Inc | Ada, OK 74820 | Oil & Gas Operator | Nov 2018 |
| 7 | Halliburton Oil Producing Co. | Duncan, OK 73534 | Oil & Gas Operator | Apr 2016 |
| 8 | Hamilton Brothers Oil Co. | Houston, TX 77057 | Oil & Gas Operator | Mar 2015 |
| 9 | Harding & Shelton Inc | Oklahoma City, OK 73104-2410 | Oil & Gas Operator | Jan 2025 |
| 10 | Harding And Shelton Exploration LLC | Oklahoma City, OK 73101-1557 | Oil & Gas Operator | Jan 2025 |
| 11 | Harken Exploration Company | Houston, TX 77079 | Oil & Gas Operator | Mar 2008 |
| 12 | Harrell Petroleum Inc | Oklahoma City, OK 73102-7201 | Oil & Gas Operator | Oct 2017 |
| 13 | Hawkins Oil & Gas Inc | Tulsa, OK 74103 | Oil & Gas Operator | Dec 2016 |
| 14 | HCL Inc | Woodward, OK 73802-1074 | Oil Operator | Mar 2015 |
| 15 | Headington Oil Company | Dallas, TX 75231 | Oil & Gas Operator | Dec 2016 |
| 16 | Henderson Don Inc | Oklahoma City, OK 73134-1753 | Oil & Gas Operator | Aug 2013 |
| 17 | Hess Corporation | Houston, TX 77010 | Oil & Gas Operator | Aug 2017 |
| 18 | High Sierra Crude Oil& Marketing LLC | Ardmore, OK 73401 | Oil Operator | Nov 2013 |
| 19 | Highland Oil & Gas LLC | Houston, TX 77079-7220 | Oil & Gas Operator | Feb 2015 |
| 20 | Highmark Energy Operating, LLC | Dallas, TX 75222 | Oil & Gas Operator | Apr 2025 |
| 21 | Highway 15 SWD LLC | Shattuck, OK 73858 | Oil Operator | Oct 2021 |
| 22 | Highway 60 SWD LLC | Shattuck, OK 73858-0848 | Oil Operator | Jul 2019 |
| 23 | Hill John H | Dallas, TX 75240-7077 | Oil & Gas Operator | Jul 2015 |
| 24 | Himco Oil & Gas, Inc. | Enid, OK 73702 | Oil & Gas Operator | Jan 2025 |
| 25 | Hines Oil & Gas LLC | Elk City, OK 73644-9373 | Gas Operator | Aug 2021 |
| 26 | Hodgden Operating Co., Inc. | Enid, OK 73702 | Oil & Gas Operator | Feb 2025 |
| 27 | Hog Operating LLC | Dallas, TX 75201 | Oil & Gas Operator | Apr 2025 |
| 28 | Holland Exploration Company | | Oil & Gas Operator | Apr 2007 |
| 29 | Home Petroleum Corp | Victoria, TX 77902 | Oil & Gas Operator | Apr 2025 |
| 30 | Home-Stake Royalty Corp., The | Tulsa, OK 74103 | Oil & Gas Operator | Feb 2014 |
| 31 | Hondo Oil & Gas Company | Roswell, NM 88202 | Oil & Gas Operator | Aug 2006 |
| 32 | Horizon Natural Gas Company | Tulsa, OK 74170 | Oil & Gas Operator | Oct 2024 |
| 33 | Horizon Natural Resources, Inc. | Tulsa, OK 74136 | Oil & Gas Operator | Jan 2019 |
| 34 | Houseco Petroleum Inc | Bristow, OK 74010-0842 | Oil & Gas Operator | Aug 2002 |
| 35 | Huber J M Corp | Edison, NJ 08837 | Oil & Gas Operator | Apr 2025 |
| 36 | Hugoton Energy Corporation | Oklahoma City, OK 73113 | Oil & Gas Operator | Dec 2019 |
| 37 | Hulen Operating Company | Nichols Hill, OK 73116 | Oil & Gas Operator | Apr 2025 |
| 38 | Hunt Energy Corporation | | Oil & Gas Operator | Feb 2002 |
| 39 | Huntington Energy LLC | Nichols Hill, OK 73116 | Oil & Gas Operator | Apr 2025 |
| 40 | Hunton Oil & Gas Corporation | Oklahoma City, OK 73154-0191 | Oil & Gas Operator | May 2019 |