| 1 | East Texas Crude Oil Corporation | Tyler, TX 75701 | Oil & Gas Operator | Jun 1994 |
| 2 | Edge Petroleum Oper. Co., Inc. | Houston, TX 77042 | Oil & Gas Operator | Nov 2010 |
| 3 | Elliott Oil & Gas Operating Co. | Magnolia, TX 77354 | Oil & Gas Operator | Dec 2025 |
| 4 | Empire Texas Operating LLC | The Woodlands, TX 77380 | Oil & Gas Operator | Dec 2025 |
| 5 | Encana Oil & Gas (USA) Inc. | Denver, CO 80202 | Oil & Gas Operator | Oct 2020 |
| 6 | Energy & Expl. PRTNRS Oper., LP | Fort Worth, TX 76147 | Oil & Gas Operator | Oct 2016 |
| 7 | Energy Development Corporation | Houston, TX 77067 | Oil & Gas Operator | Dec 2024 |
| 8 | Energy Transfer Crude Marketing LLC | Dallas, TX 75225 | Oil Operator | Aug 2025 |
| 9 | Enserch Exploration Inc | Dallas, TX 75206 | Oil & Gas Operator | Apr 2015 |
| 10 | EOG Resources Inc | Midland, TX 79702 | Oil & Gas Operator | Dec 2025 |
| 11 | Etc Texas Pipeline, LTD. | Dallas, TX 75225 | Oil Operator | Sep 2023 |
| 12 | Etoco, L.P. | Houston, TX 77002 | Oil & Gas Operator | Dec 2025 |
| 13 | Etx Energy, LLC | Tulsa, OK 74136 | Oil & Gas Operator | Oct 2022 |
| 14 | Exploration Company, The | San Antonio, TX 78258 | Oil & Gas Operator | Jun 2010 |
| 15 | Exxon Corporation | Houston, TX 77210 | Oil & Gas Operator | Jun 2024 |