Hydrate Prevention Strategy Research Of Deep Sea Gathering And Transportation System Based On OLGA

The deep-sea is the strategic place of the world’s oil and gas energy in the future.The development of deep-sea oil and gas energy is inseparable from the multiphase flow gathering and transportation system.Hydrate is a flow guarantee problem that has been perplexing the safe and stable operation of deep water gathering and transportation system.Shallow water hydrate prevention and control measures are difficult to be directly applied to the deep sea.Therefore,this paper takes the research on hydrate prevention strategy of deep-sea gathering and transportation system based on OLGA as the topic,puts forward hydrate prevention measures for different operating conditions of M deep-sea gathering and transportation system,and finally puts forward solutions to the hydrate blockage problem of deep-sea gathering and transportation system.Firstly,this paper uses OLGA software to simulate and predict the hydrate formation problem of M deep-sea gathering and transportation system in the whole life cycle operations such as initial start-up,steady state operation,shutdown and restart.It is found that M deep-sea gathering and transportation system always is in the hydrate formation interval in the steady-state operation stage,and the downstream of the choke is in the hydrate formation interval in part of the time of initial start-up and shutdown and restart conditions.Then it puts forward targeted prevention measures for different operating conditions.Under steady-state operation conditions,hydrate is formed for a long time.It is proposed to inject recyclable chemical glycol to prevent and control hydrate,and the injection amount in the lately field life is 491m~3/d.Under the initial start-up condition and shutdown and restart condition,it is proposed to inject methanol with wide temperature range and high prevention and control efficiency to prevent and control hydrate.In the cold start-up condition,it is proposed to reduce the use of methanol by time and segment injection method and improve economic benefits.Finally,simulate the bilateral depressurized method for hydrate unblocking analysis,and predict that M deep-sea gathering and transportation system will take at least 322hours to complete hydrate emergency unblocking.