The company said the BW Athena will stay with the company until the second quarter of 2020 after Ithaca exercised an option.
The oil company has the right to terminate the contract with 12 months notice however.
The FPSO is employed on the Athena oil field in the UK.
It was built in 1994 and converted to an FPSO in 1999.
BW Athena has production capacity of 28,000 barrels per day and storage capacity of 50,000 barrels.
