| 1 | El Paso E&P Company, L.P. | Houston, TX 77002 | Oil & Gas Operator | Mar 2013 |
| 2 | El Paso Natural Gas Company | El Paso, TX 79978 | Oil & Gas Operator | Apr 2013 |
| 3 | El Paso Production Oil & Gas Co. | Houston, TX 77252 | Oil & Gas Operator | Nov 2024 |
| 4 | Elk Production LLC | Denver, CO 80202 | Oil & Gas Operator | Aug 2011 |
| 5 | Elk Production Uintah LLC | Denver, CO 80202 | Oil & Gas Operator | Dec 2014 |
| 6 | Elk Resources, LLC | Denver, CO 80202 | Oil & Gas Operator | Apr 2011 |
| 7 | Encana Oil & Gas (USA) Inc. | Denver, CO 80202 | Oil & Gas Operator | Oct 2020 |
| 8 | Enduring Resources, LLC | Greenwood VLG, CO 80111 | Oil & Gas Operator | Sep 2024 |
| 9 | Energy Reserves Group | Houston, TX 770563020 | Oil & Gas Operator | Apr 1996 |
| 10 | Enerplus Resources USA Corporation | Denver, CO 80202 | Oil & Gas Operator | Sep 2024 |
| 11 | Enogex Exploration Corp | Oklahoma City, OK 73124-0300 | Oil & Gas Operator | Jun 2000 |
| 12 | Enron Oil & Gas Company | Houston, TX 77210 | Oil & Gas Operator | Dec 1999 |
| 13 | Enserch Exploration Inc | Dallas, TX 75206 | Oil & Gas Operator | Apr 2015 |
| 14 | EOG Resources Inc | Midland, TX 79702 | Oil & Gas Operator | Nov 2024 |
| 15 | EP Energy E&P Company, LP | Houston, TX 77210 | Oil & Gas Operator | May 2022 |
| 16 | EP Operating Company LP | Midland, TX 79705-5510 | Oil & Gas Operator | Mar 1993 |
| 17 | Eps Resources Corp | Englewood, CO 80111 | Oil & Gas Operator | Dec 2009 |
| 18 | Equitable Resources Energy | Houston, TX 77056-2742 | Oil & Gas Operator | Sep 1997 |
| 19 | Equity Oil Company | Salt Lake City, UT 84110-095 | Oil & Gas Operator | Aug 2004 |
| 20 | Evergreen Operating Corp | Denver, CO 80202 | Oil & Gas Operator | Dec 2019 |
| 21 | Exxon Corporation | Houston, TX 77210 | Oil & Gas Operator | Jun 2024 |