Development of downhole hydroclone for liquid-sand separation and its application

Pump abrasion caused by sand production is a common problem during high water cut period.To solve the problem,a downhole hydroclone for liquid-sand separation is designed on the basis of experience and numerical simulation.The effects of liquid viscosity,sand content and flow rate on separating effect are analyzed.Resultsshow that liquid viscosity is the main factor affecting the separating effect,as well as the increase of liquid viscosity lowers the separating effect.So downhole hydroclone for liquid-sand separation is only suitable for wells of light oil or ultrahigh watercut.Sand cut has little effect on separating effect when it is less than 10%.There is a suitable flowrate zoon to select the diameter of downhole hydroclone,which can be determined by the production of wells.Field application shows that the downhole hydroclone is an effective facility to decrease the sand content of produced liquid before it is pumped,to improve the pump efficiency,to prolong the pump's working life by 60 days on average,and to diminish the failures of stuck pump caused by sands remarkably.