Pluggsystem og fremgangsmåte for å bruke plugger i underjordiske formasjoner

摘要

A method of cementing a casing string in a subterranean well bore characterised by the steps of: injecting a cement composition into the casing string; and deploying within the casing string at least one cementing plug (10,20,60) comprising an outer body (11,21) and a detachable inner mandrel (13,23) attached to the outer body (11,21).