Two Japanese firms have agreed to buy 50% of Akofs Offshore from Norwegian oil service investor Akastor for $142.5 million.
Mitsui & Co and Mitsui OSK Lines (MOL) will each own 25% of Akofs once the deal goes through.
The deal is expected to go through in the third quarter.
Mitsui and MOL are guaranteed a return during the first six years of operations, limited to about $46m.
Akastor may claim earn-out payments during the first seven years of operations, limited to $45m.