| Company Name | Company Location | Company Type | Most Recent Production | |
|---|---|---|---|---|
| 1 | Umc Petroleum Corporation | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 2 | Union Oil Co Of California | Midland, TX 79706 | Oil & Gas Operator | Jan 2022 |
| 3 | Union Pacific Resources Co. | Fort Worth, TX 76101 | Oil & Gas Operator | Sep 2002 |
| 4 | Unit Petroleum Company | Tulsa, OK 74170 | Oil & Gas Operator | Oct 2025 |
| 5 | United Resources LP | Austin, TX 78746 | Oil & Gas Operator | Oct 2011 |
| 6 | Uplands Resources Inc | Tulsa, OK 74103-4141 | Oil & Gas Operator | Jun 2025 |
| 7 | Uptex Operating Inc. | Dallas, TX 75201 | Oil & Gas Operator | May 2011 |
| 8 | Uptex Operating, L.P. | Dallas, TX 75201 | Oil & Gas Operator | May 2010 |