Abstract: An oilfield group in the southern Bohai Sea transmits crude oil to the land terminal through oilfield A. The offshore pipeline of oilfield A transports multi well mixed oil products. The properties of the oil products are extremely complex. The content of crude oil colloid,asphaltene and wax is high,the freezing point is high,and the transmission distance is long,resulting in some difficulties in the production and operation of the pipeline. After many studies and tests,A oilfield has prepared appropriate pour point depressant,which solves the problem of high freezing point in the operation of subsea pipeline,greatly reduces the minimum transmission capacity of subsea pipeline,and effectively prevents the congelation.

Key words: subsea pipeline, freezing point, pour point depressant, minimum transmission capacity, safe shutdown time