SAND FILTER AND METHOD OF MANUFACTURE

摘要

Cylindrical screens and screen assemblies for use with perforated base pipe or casing for sand control in wellbores have generally longitudinally extending slots punched in the screen. The outer surface of the screen material is deformed below the inner surface causing apertures to form along the longitudinal edges of the slot. The slots are generally longitudinally aligned with the longitudinal axis of the cylindrical screens whether butt-welded or spiral-rolled and welded by determining the angle at which the slots need to be punched to result in such alignment. End caps which connect between the screen and the casing extend over the ends of the cylindrical screen and are welded thereto to minimize sand entry. At least one of the end caps may include an expansion joint to permit relative expansion and contraction between the screen and the casing particularly when used in thermal recovery operations.