| Company Name | Company Location | Company Type | Most Recent Production | |
|---|---|---|---|---|
| 1 | O'Brien Energy Resources Corp | Portsmouth, NH 03801 | Oil & Gas Operator | Dec 2024 |
| 2 | Oil Producers, Inc. Of Kansas | Wichita, KS 67206 | Oil & Gas Operator | Dec 2024 |
| 3 | Oil Property Man | Oil & Gas Operator | Jun 1995 | |
| 4 | Oleum Incorporat | Gas Operator | Dec 1990 | |
| 5 | Oneok Exploratio | Oil & Gas Operator | Mar 1995 | |
| 6 | Oryx Energy Comp | Oil & Gas Operator | Apr 1991 | |
| 7 | Oryx Energy Company | Dallas, TX 75221 | Oil & Gas Operator | May 2002 |
| 8 | Oxy USA Inc | Houston, TX 77046 | Oil & Gas Operator | Dec 2024 |