| 1 | E. T. S. Enterprises, Inc. | Amarillo, TX 79105 | Oil & Gas Operator | Jul 1996 |
| 2 | Earlsboro Energies Corporation | Oklahoma City, OK 73116-3605 | Oil & Gas Operator | Jun 2025 |
| 3 | Edinger Engineering, Inc. | Oklahoma City, OK 73102 | Oil & Gas Operator | Jul 2025 |
| 4 | El Paso Natural Gas Company | El Paso, TX 79978 | Oil & Gas Operator | Apr 2013 |
| 5 | El Paso Production Company | Houston, TX 77002 | Oil & Gas Operator | Mar 2016 |
| 6 | Elite Tank Trucks, Inc | | Oil & Gas Operator | Jul 2025 |
| 7 | Encana Energy Resources Inc | Denver, CO 80202-2828 | Oil & Gas Operator | Feb 2024 |
| 8 | Enervest Operating LLC | Houston, TX 77002 | Oil & Gas Operator | Oct 2025 |
| 9 | EOG Resources, Inc. | Midland, TX 79702 | Oil & Gas Operator | Oct 2025 |
| 10 | Eott Energy Operating LP | Houston, TX 77210-4666 | Oil & Gas Operator | Oct 2009 |
| 11 | Evolution Energy LLC | Oklahoma City, OK 73116 | Oil & Gas Operator | Jul 2025 |
| 12 | Exoko Operating Company Inc | Tulsa, OK 74170-0246 | Oil & Gas Operator | Jan 2006 |
| 13 | Exxon Mobil Corporation | Spring, TX 77389 | Oil & Gas Operator | Oct 2025 |
| 14 | Exxonmobil Oil Corp | Houston, TX 77210 | Oil & Gas Operator | Jul 2025 |