| Company Name | Company Location | Company Type | Most Recent Production | |
|---|---|---|---|---|
| 1 | O'Brien Energy Resources Corp | Portsmouth, NH 03801 | Oil & Gas Operator | Nov 2024 |
| 2 | Ocean Energy Inc | Houston, TX 77002 | Oil & Gas Operator | Aug 2003 |
| 3 | Oildigger Resources Fund L LLLP | Billings, MT 59101 | Oil & Gas Operator | Sep 2024 |
| 4 | Okie Crude Company | Tulsa, OK 74103 | Oil & Gas Operator | Sep 2024 |
| 5 | Olds Oil Company | Casper, WY 82604 | Oil Operator | Jun 1988 |
| 6 | Oryx Energy Company | Dallas, TX 75221 | Oil & Gas Operator | May 2002 |
| 7 | Osborn Heirs Company LTD | San Antonio, TX 78217 | Oil & Gas Operator | Jul 2024 |
| 8 | Oxford Exploration Company | Denver, CO 80237 | Oil & Gas Operator | Aug 1995 |
| 9 | Oxy USA Inc | Houston, TX 77046 | Oil & Gas Operator | Nov 2024 |