| 1 | H2ok LLC | | Oil & Gas Operator | Feb 2024 |
| 2 | H2ox Operating LLC | | Oil Operator | Feb 2024 |
| 3 | Hadson Petro USA Inc | | Oil & Gas Operator | Nov 2016 |
| 4 | Hadson Petroleum Corporation | Oklahoma City, OK 73102 | Oil & Gas Operator | Mar 2015 |
| 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 Energy Company LLC | Oklahoma City, OK 73120-5020 | Oil & Gas Operator | Jul 2022 |
| 8 | Halliburton Oil Producing Co. | Duncan, OK 73534 | Oil & Gas Operator | Apr 2016 |
| 9 | Hallwood Petroleum, Inc. | Midland, TX 79701 | Oil & Gas Operator | Dec 2023 |
| 10 | Ham Oil Company, LLC | | Oil Operator | Sep 2022 |
| 11 | Hamil Oil & Gas LLC | | Oil & Gas Operator | Jan 2024 |
| 12 | Harding & Shelton Inc | Oklahoma City, OK 73104-2410 | Oil & Gas Operator | Jan 2024 |
| 13 | Harken Exploration Company | Houston, TX 77079 | Oil & Gas Operator | Mar 2008 |
| 14 | Harris Minerals Corp (The) | Oklahoma City, OK 73162-1045 | Oil & Gas Operator | Jan 2024 |
| 15 | Haydens Oil And Gas LLC | | Oil & Gas Operator | Jan 2024 |
| 16 | Hazelwood Prod & Exp Co LLC | Oklahoma City, OK 73116-9037 | Oil & Gas Operator | Dec 2023 |
| 17 | Hazlewood Oil & Gas Co Inc | Oklahoma City, OK 73139-9353 | Oil & Gas Operator | Apr 2022 |
| 18 | HCM | Dallas, TX 75206 | Oil & Gas Operator | Mar 2015 |
| 19 | Headington Oil Company | Dallas, TX 75231 | Oil & Gas Operator | Dec 2016 |
| 20 | Heartland Environmental Services | | Oil & Gas Operator | May 1999 |
| 21 | Heartlands Development Co Inc | Bristow, OK 74010-3826 | Oil & Gas Operator | May 2017 |
| 22 | Helmerich & Payne, Inc. | Tulsa, OK 74114 | Oil & Gas Operator | Jan 2024 |
| 23 | Hennessey Oil & Gas LLC | Hennessey, OK 73742-0212 | Oil & Gas Operator | Jan 2024 |
| 24 | Hep Oil Company LTD | Gainesville, TX 76240 | Oil & Gas Operator | Mar 2012 |
| 25 | Heritage Petroleum, Inc. | Stillwater, OK 74076 | Oil & Gas Operator | Apr 2024 |
| 26 | High Sierra Crude Oil& Marketing LLC | Ardmore, OK 73401 | Oil Operator | Nov 2013 |
| 27 | High Sierra Water Services Mid Continent LLC | Denver, CO 80209 | Oil Operator | Feb 2010 |
| 28 | Highland Minerals, Inc. | Tulsa, OK 74145-7627 | Oil & Gas Operator | Apr 2015 |
| 29 | Himco Oil & Gas, Inc. | Enid, OK 73702 | Oil & Gas Operator | Jan 2024 |
| 30 | Hinkle Engineering, Inc. | Oklahoma City, OK 73112 | Oil & Gas Operator | Nov 2016 |
| 31 | Hinkle Oil And Gas Inc | Oklahoma City, OK 73112-4275 | Oil & Gas Operator | Feb 2024 |
| 32 | HK Energy Operating, LLC | Houston, TX 77002 | Oil & Gas Operator | May 2023 |
| 33 | Hoard John L Family Trust | Ardmore, OK 73402-1706 | Oil & Gas Operator | Jun 2022 |
| 34 | Hodgden Operating Co., Inc. | Enid, OK 73702 | Oil & Gas Operator | Feb 2024 |
| 35 | Hondo Oil & Gas Company | Roswell, NM 88202 | Oil & Gas Operator | Aug 2006 |
| 36 | Honeymon Drilling Company LTD | Oklahoma City, OK 73147 | Oil & Gas Operator | Feb 1995 |
| 37 | Horizon Natural Gas Company | Tulsa, OK 74170 | Oil & Gas Operator | Jan 2024 |
| 38 | Horizon Natural Resources, Inc. | Tulsa, OK 74136 | Oil & Gas Operator | Jan 2019 |
| 39 | HPC Incorporated | Denver, CO 80202 | Oil & Gas Operator | Nov 1998 |
| 40 | Hsumy Oil & Gas Inc | Oklahoma City, OK 73102 | Oil & Gas Operator | Apr 2007 |
| 41 | Hughes Gas Systems LLC | Oklahoma City, OK 73118-4821 | Oil & Gas Operator | Jan 2024 |
| 42 | Hugoton Energy Corporation | Oklahoma City, OK 73113 | Oil & Gas Operator | Dec 2019 |
| 43 | Hunt Oil Company | Dallas, TX 75201 | Oil & Gas Operator | Apr 2024 |
| 44 | Hunt, H L | Dallas, TX 75202-2785 | Oil & Gas Operator | Feb 2020 |
| 45 | Huntington Energy LLC | Oklahoma City, OK 73116 | Oil & Gas Operator | Apr 2024 |
| 46 | Hux Oil Company LLC | Kingfisher, OK 73750-0474 | Oil & Gas Operator | Jan 2024 |
| 47 | Hy-Carb Energy Inc | | Oil & Gas Operator | Feb 2009 |