| 1 | H2ox Operating LLC | | Oil Operator | Feb 2024 |
| 2 | Hadson Petro USA Inc | | Oil & Gas Operator | Nov 2016 |
| 3 | Hadson Petroleum Corporation | Oklahoma City, OK 73102 | Oil & Gas Operator | Mar 2015 |
| 4 | Hagler William N | Farmington, NM 87499-0035 | Oil Operator | Apr 2014 |
| 5 | Halcon Holdings Inc | Ada, OK 74820 | Oil & Gas Operator | Nov 2018 |
| 6 | Halcyon Natural Gas LLC | Oklahoma City, OK 73116-9111 | Oil & Gas Operator | Feb 2024 |
| 7 | Hall Edward L | Ada, OK 74820-3321 | Oil & Gas Operator | Jan 2024 |
| 8 | Hallwood Petroleum, Inc. | Midland, TX 79701 | Oil & Gas Operator | Dec 2023 |
| 9 | Ham Oil Company, LLC | | Oil Operator | Sep 2022 |
| 10 | Harlow Corporation, The | Amarillo, TX 79101 | Oil & Gas Operator | Apr 2014 |
| 11 | Harris Minerals Corp (The) | Oklahoma City, OK 73162-1045 | Oil & Gas Operator | Jan 2024 |
| 12 | Heartlands Development Co Inc | Bristow, OK 74010-3826 | Oil & Gas Operator | May 2017 |
| 13 | Helmerich & Payne, Inc. | Tulsa, OK 74114 | Oil & Gas Operator | Jan 2024 |
| 14 | High Sierra Crude Oil& Marketing LLC | Ardmore, OK 73401 | Oil Operator | Nov 2013 |
| 15 | Hillin-Simon Oil Company | Houston, TX 77079 | Oil & Gas Operator | Mar 2013 |
| 16 | HK Energy Operating, LLC | Houston, TX 77002 | Oil & Gas Operator | May 2023 |
| 17 | Horizon Natural Resources, Inc. | Tulsa, OK 74136 | Oil & Gas Operator | Jan 2019 |
| 18 | Huitt Joe A | Tulsa, OK 74103 | Oil & Gas Operator | May 2001 |
| 19 | Hulsey Larry O & Co | Graham, TX 76046 | Oil & Gas Operator | Jun 2012 |
| 20 | Hunt Energy Corporation | | Oil & Gas Operator | Feb 2002 |
| 21 | Hunt Oil Company | Dallas, TX 75201 | Oil & Gas Operator | Apr 2024 |
| 22 | Hunt, H L | Dallas, TX 75202-2785 | Oil & Gas Operator | Feb 2020 |
| 23 | Hy-Carb Energy Inc | | Oil & Gas Operator | Feb 2009 |