| 1 | Eager Oil Company | Stanhope, NJ 07874-0577 | Oil Operator | Jun 2014 |
| 2 | Eakin Exploration Inc | Tulsa, OK 74136 | Oil & Gas Operator | Jun 2016 |
| 3 | Earl Oil Inc | Stillwater, OK 74074-1079 | Oil & Gas Operator | Feb 2024 |
| 4 | Earthstone Operating, LLC | The Woodlands, TX 77380 | Oil & Gas Operator | May 2024 |
| 5 | Eastern Petroleum Company | Girard, OH 44420 | Oil & Gas Operator | Sep 1995 |
| 6 | Ecc Energy Corporation | Dewey, OK 74029 | Oil & Gas Operator | Feb 2020 |
| 7 | Eei Operating Inc | Plano, TX 75093 | Oil & Gas Operator | May 2015 |
| 8 | Emjo Operations Inc | Marlow, OK 73055-8803 | Oil & Gas Operator | Feb 2024 |
| 9 | Endeavor Energy Resources, LP | Midland, TX 79701 | Oil & Gas Operator | May 2024 |
| 10 | Energy Group Of America Inc | Hollister, MO 65672 | Oil Operator | May 2024 |
| 11 | Energy Lease Service Inc | Drumright, OK 74030-7403 | Oil & Gas Operator | Jan 2024 |
| 12 | Energyquest Management, LLC | Houston, TX 77090 | Oil & Gas Operator | Apr 2021 |
| 13 | Enertec Corporation | Nowata, OK 74048-0632 | Oil & Gas Operator | Sep 2018 |
| 14 | Envirotek Fuel Systems Inc | Dallas, TX 75243 | Oil & Gas Operator | May 2013 |
| 15 | Equinox Oil Company | Plainville, KS 67663 | Oil & Gas Operator | Jan 2024 |
| 16 | Equity Drilling Company Inc | Dewey, OK 74029 | Oil & Gas Operator | Nov 1998 |
| 17 | Escott Oil Inc | Nowata, OK 74048 | Oil & Gas Operator | Feb 2000 |
| 18 | Exploration Professionals Inc | Chelsea, OK 74016 | Oil Operator | Dec 2023 |
| 19 | Exploration Technologies Inc | Crescent, OK 73028-0546 | Oil & Gas Operator | Mar 2015 |