TELESCOPING CENTRALIZERS FOR EXPANDABLE TUBULARS

摘要

A method of centralizing tubulars prior to cementing and subsequent expansion involves using a plurality of telescoping cylinders whose leading or trailing end is closed and which are extended by applied internal pressure in the tubular or some mechanical means. The tubular is expanded from its interior with the cylindrical telescoping members still extended. The cement is pushed all around the tubular due to the centralizers. After the cement is delivered the expansion of the tubular pushes the telescoping members into the borehole wall.