The fund was closed after exceeding its initial target, Blue Water said in a statement. It has so far invested in three firms -- Norway-focused Mime Petroleum, infrastructure company GPS Group and Authentix, which provides services for oil trading.

The fund is the second Blue Water has launched in recent years. It used the first $862 million fund, launched in 2013, to invest in North Sea producer Siccar Point, a joint venture with Blackstone that acquired a $1 billion portfolio of asset from Austria's OMV.

A number of leading private equity funds have invested billions in oil and gas assets around the world in recent years, hoping to generate strong returns as the sector emerges from the downturn since mid-2014.

(Reporting by Ron Bousso; Editing by Edmund Blair)

By Ron Bousso