| 1 | H G & G Inc | Edmond, OK 73034 | Oil & Gas Operator | Jan 2006 |
| 2 | H-Petro-R Inc | Edmond, OK 73013 | Oil & Gas Operator | Apr 2025 |
| 3 | Hadson Petroleum Corporation | Oklahoma City, OK 73102 | Oil & Gas Operator | Mar 2015 |
| 4 | Halcon Holdings Inc | Ada, OK 74820 | Oil & Gas Operator | Jun 2025 |
| 5 | Halliburton Oil Producing Co. | Duncan, OK 73534 | Oil & Gas Operator | Apr 2016 |
| 6 | Hamil Oil & Gas LLC | Kingfisher, OK 73750-6500 | Oil & Gas Operator | Jul 2025 |
| 7 | Harbor Resources LLC | Oklahoma City, OK 73120 | Oil & Gas Operator | Oct 2025 |
| 8 | Hardin Productions | Okemah, OK 74859 | Oil & Gas Operator | Dec 2006 |
| 9 | Harken Exploration Company | Houston, TX 77079 | Oil & Gas Operator | Mar 2008 |
| 10 | Harrell Verlan W | Oklahoma City, OK 73102-7201 | Oil & Gas Operator | Nov 1999 |
| 11 | Harris Oil & Gas Company | Denver, CO 80202 | Oil & Gas Operator | Jun 2016 |
| 12 | Hazelwood Prod & Exp Co LLC | Oklahoma City, OK 73116-9037 | Oil & Gas Operator | Jun 2025 |
| 13 | HCM | Dallas, TX 75206 | Oil & Gas Operator | Mar 2015 |
| 14 | Heartland Pumping | Hennessey, OK 73742-7311 | Oil & Gas Operator | Jul 2025 |
| 15 | Hemstead Oil Corporation | Oklahoma City, OK 73102 | Oil & Gas Operator | May 2001 |
| 16 | Hennessey Oil & Gas LLC | Hennessey, OK 73742-0212 | Oil & Gas Operator | Sep 2024 |
| 17 | Henry Gungoll Operating Inc | Enid, OK 73703 | Oil & Gas Operator | Jul 2025 |
| 18 | Hep Oil Company LTD | Gainesville, TX 76240 | Oil & Gas Operator | Mar 2012 |
| 19 | Hep Oil GP, LLC | Gainesville, TX 76241 | Oil & Gas Operator | Mar 2015 |
| 20 | Heritage Petroleum, Inc. | Stillwater, OK 74076 | Oil & Gas Operator | Oct 2025 |
| 21 | High Energy | Cushing, OK 74023 | Oil & Gas Operator | May 2025 |
| 22 | Highland Minerals, Inc. | Tulsa, OK 74145-7627 | Oil & Gas Operator | Apr 2015 |
| 23 | Hill Oil Company Inc | Shawnee, OK 74804 | Oil & Gas Operator | Jun 2025 |
| 24 | Hill Resources Inc | | Oil & Gas Operator | Nov 2022 |
| 25 | Hinkle Engineering, Inc. | Oklahoma City, OK 73112 | Oil & Gas Operator | Nov 2016 |
| 26 | Hinkle Oil And Gas Inc | Oklahoma City, OK 73112-4275 | Oil & Gas Operator | Jul 2025 |
| 27 | Hodgden Operating Co., Inc. | Enid, OK 73702 | Oil & Gas Operator | Jul 2025 |
| 28 | Holden Energy Corporation | Ardmore, OK 73401 | Oil & Gas Operator | Mar 2015 |
| 29 | Honeymon Drilling Company LTD | Oklahoma City, OK 73147 | Oil & Gas Operator | Feb 1995 |
| 30 | Horizon Natural Gas Company | Tulsa, OK 74170 | Oil & Gas Operator | Oct 2024 |
| 31 | Horizon Natural Resources, Inc. | Tulsa, OK 74136 | Oil & Gas Operator | Jan 2019 |
| 32 | Huitt Joe A Rev Trust | Tulsa, OK 74103 | Oil & Gas Operator | Oct 2009 |
| 33 | Hulen Operating Company | Nichols Hill, OK 73116 | Oil & Gas Operator | Oct 2025 |
| 34 | Hungerford Oil & Gas Inc | Helena, OK 73741 | Oil & Gas Operator | Nov 2000 |
| 35 | Hunt Oil Company | Dallas, TX 75201 | Oil & Gas Operator | Oct 2025 |
| 36 | Hunton Oil & Gas Corporation | Oklahoma City, OK 73154-0191 | Oil & Gas Operator | May 2019 |
| 37 | Hunton Operating LLC | Oklahoma City, OK 73154 | Oil & Gas Operator | Jun 2025 |
| 38 | Husky Ventures Inc | Oklahoma City, OK 73134 | Oil & Gas Operator | Jun 2025 |
| 39 | Hux Oil Company LLC | Kingfisher, OK 73750 | Oil & Gas Operator | Jul 2025 |
| 40 | Hyalite Energy Corporation | Pampa, TX 79066 | Oil & Gas Operator | May 2025 |