Experimental Study On Response Characteristics Of Gas-water Severe Slug Flow In The Composite Pipeline-riser System

Severe Flow often occur to the equipment which mixing oil and gas flow in deep sea with low velocity.As an unstable pattern in practical production,it always bring lots of problem:decrease oil production,increase mechanical abrasion degree,aggravate corrosion of riser pipeline and so on.For this reason,the research of severe slug flow should be carry out systematic.In the condition of self-building experimental platform,relying on the multi-phase flow lab in the Xi'an Shiyou University,in this paper,the experiment on the response characteristics of the gas-water severe slug flow in the composite pipeline-riser system is conducted.The main research are as below:Systematically studied the pressure and differential pressure fluctuation characteristics of severe slug flow in riser pipeline system,the results show that the severe slug flow pressure and differential pressure are present a kind of stable cyclical fluctuations,which decreased with increasing inclination angle and liquid/gas superficial velocity;The minimum of the pressure increase with increasing liquid superficial velocity,decrease with increasing gas superficial velocity.The system pressure of SS ? is lower than SS ? and differential pressure of SS ? is lower than SS ?.The signal of severe slug flow showing a diversity of distribution unmoral,bimodal and multimodal,but the probability density distribution of differential pressure signal of SS ? and SS ? is mainly characterized by an bimodal distribution while SS ? is mainly characterized by an unmoral distribution in riser pipeline system.The power spectral density of differential pressure fluctuation frequency are stability and small range.As for stable flow,the pressure and differential pressure presented lower,probability density dispersion seems narrow and maximum of power spectral density of differential pressure fluctuation assumed lower.Wire probes has been adopted to measure liquid holdup of severe slug flow.The result of liquid hold up are as follow:The liquid holdup performance for the obvious periodical change characteristics.The period of liquid increase with the decrease of the gas superficial velocity,the liquid superficial velocity and inclination angle.The probability density distribution of liquid holdup signal is mainly characterized by an bimodal distribution of SS ? and SS ? but SS? is unmoral distribution;The power spectral density of liquid holdup fluctuation frequency has the characteristics of stability and small range.