Method of using a surface jet pump to mitigate severe slugging in pipes and risers

Abstract

A slug mitigation system for subsea pipelines that includes a riser located between a low subsea level and an upper topside level of a pipeline. There is also a separator located at the top of the riser; and a surface jet pump located at a gas outlet of the separator. In another embodiment of a slug mitigation system, the surface jet pump is located downstream of an in-line separator on a gas outlet using high pressure gas from a downstream process or compressor.

What is claimed is: 
     
         1 . A slug mitigation system for subsea pipelines including:
 a riser located between a low sub-sea level and an upper topside level of a pipeline;   a separator located at the top of the riser; and   a surface jet pump located at a gas outlet of the separator.   
     
     
         2 . The slug mitigation system of  claim 1  wherein the surface jet pump is powered by high pressure gas available from an export compressor outlet or from its recycled gas stream. 
     
     
         3 . A slug mitigation system for subsea pipelines including:
 a riser located between a low sub-sea level and an upper topside level of a pipeline;   a surface jet pump located at the upper topside level of the pipeline, downstream of the riser;   wherein the surface jet pump is located downstream of an in-line separator on a gas outlet using high pressure gas from a downstream process or compressor.   
     
     
         4 . The slug mitigation system of  claim 3  wherein a main production separator at the top of the riser can be by-passed or operated in parallel with the inline separator and surface jet pump. 
     
     
         5 . The slug mitigation system of  claim 3  wherein produced gas can go to a gas outlet and produced liquid joins the liquid line upstream of a liquid pump.