Supermajors circling one of the most sought-after exploration blocks in southern Africa’s sizzling Orange basin now know the scale of potential resource they are dealing with.

An independent report has estimated the Africa Oil-operated acreage could hold 3 billion barrels of oil and 5.5 trillion cubic feet of gas.

London-listed Africa Oil and its partners in Block 3B/4B offshore South Africa are in the middle of a farm-out exercise that has attracted a raft of potential suitors, with the aim of wrapping up a deal within months so two exploration wells can be drilled next year.