China Oilfield Services (COSL) is selling a couple of subsea survey ships to its affiliate Shenzhen COOEC.
The 9,700-dwt Hai Yang Shi You 701 and Hai Yang Shi You 702 (both built 2016) are costing CNY 1.06bn ($241m) in total.
Chinese oil company CNOOC owns both companies.
COSL said it had closely followed changes in market demand and was proactively improving the asset structure of the company.