| 1 | Eason Oil Company | Oklahoma City, OK 73112 | Oil & Gas Operator | Mar 2012 |
| 2 | Enerco Exploration & MGMT. Co. | | Oil & Gas Operator | Aug 1981 |
| 3 | Enervest Operating LLC | Houston, TX 77002 | Oil & Gas Operator | Nov 2024 |
| 4 | Enervest Production Partners, LTD. | | Gas Operator | Jun 2024 |
| 5 | Ensight Energy Management, LLC | Shreveport, LA 71101 | Oil & Gas Operator | Jul 2005 |
| 6 | Ensight III Energy MGMT, LLC | Shreveport, LA 71101 | Oil & Gas Operator | Apr 2008 |
| 7 | Ensight IV Energy Management,LLC | Shreveport, LA 71101 | Oil & Gas Operator | Jul 2024 |
| 8 | Ensight Resources, L.L.C. | Shreveport, LA 71101 | Oil & Gas Operator | Apr 2001 |
| 9 | Equitable Petroleum Corp. | | Oil & Gas Operator | Jan 1999 |
| 10 | Et Gathering & Processing LLC | San Antonio, TX 78258 | Oil Operator | Jun 2024 |
| 11 | Etc Field Services LLC | San Antonio, TX 78258 | Oil Operator | Jun 2018 |
| 12 | Etc Texas Pipeline, LTD. | San Antonio, TX 78258 | Oil Operator | Sep 2023 |