| Company Name | Company Location | Company Type | Most Recent Production | |
|---|---|---|---|---|
| 1 | O'Brien Energy Company | Shreveport, LA 71136 | Oil & Gas Operator | Sep 2019 |
| 2 | O'Brien Operating Company | Oil & Gas Operator | Dec 2004 | |
| 3 | O. B. Mobley | Oil & Gas Operator | Jul 1989 | |
| 4 | O. O. Cummings | Gas Operator | Jan 1999 | |
| 5 | O.G.P. Operating, Inc. | Dallas, TX 75231 | Oil & Gas Operator | May 2024 |
| 6 | Oak Energy, LLC | Houston, TX 77027 | Oil & Gas Operator | May 2024 |
| 7 | Occidental Energy Company, Inc. | Houston, TX 77282 | Oil & Gas Operator | Jul 2021 |
| 8 | Offshore Shelf LLC | Oil & Gas Operator | Dec 2007 | |
| 9 | Oliditt Corporation | Gas Operator | Mar 2022 | |
| 10 | Opal Oil Inc. | Oil Operator | Sep 2021 | |
| 11 | Ora Oil Company | Oil & Gas Operator | May 2017 | |
| 12 | Owl Creek Production Co., Inc. | Houston, TX 77027 | Oil & Gas Operator | Apr 2006 |