Methods and hydraulically expandable self-cleaning sand screens

Abstract

A method for cleaning a helical spring screen deep in a well while filtering liquid comprises (1) injecting a high pressure hydraulic surge pulse into the spring screen for expanding the coils, (2) forcing high pressure liquid between the coils of the helical spring screen simultaneously with expanding of the coils for washing the sand from between the coils, and (3) forcing the coils together following their expansion by expanding action of a second spring for crushing and dislodging any sand therebetween the coils for removal upon subsequent spreading of the coils. A second method is disclosed likewise. Methods for forming a self-cleaning helical spring screen and two modifications of a helical spring screen are disclosed herein for being cleaned for a multiplicity of times without having to shut the well in for workover, thus saving workover costs and lost production.