- Aspen Exploration Corp
- Bonanza Creek Oil Co
- Central Pacific Resources
- Crimson Resource Management
- Enerfin Resources Co
- Fairhaven Oil Co
- Griffin Resources
- Independent Oil Producers
- Petro Capital Resources LLC
- Petro Resources Inc
- Plains Exploration/Production
- Riverview Resources
- Sequoia Exploration Inc
- Stockdale Oil & Gas Inc
- Temblor Petroleum Co
- Trio Petroleum Inc
- Vaquero Energy Inc
- Western Continental Operating
- Xtend Oil Well Svc
