| Company Name | Company Location | Company Type | Most Recent Production | |
|---|---|---|---|---|
| 1 | O'Donnell Oil LLC | Oil & Gas Operator | Dec 2024 | |
| 2 | Occidental Petroleum Corporation | Oil & Gas Operator | Dec 2021 | |
| 3 | Oil Operators Inc. | Oil & Gas Operator | Nov 2024 | |
| 4 | Ojai Oil Company | Camarillo, CA 93012 | Oil & Gas Operator | Dec 2024 |
| 5 | Old Field Associates | Oil & Gas Operator | Dec 2024 | |
| 6 | Oryx Energy Company | Dallas, TX 75221 | Oil & Gas Operator | May 2002 |
| 7 | Oxy USA Inc | Houston, TX 77046 | Oil & Gas Operator | Mar 2025 |