Underbalanced well completion

摘要

A method of operating an apparatus within a subterranean well. The apparatus includes a structure which is displaced to operate the apparatus. The method comprises the steps of: conveying a shifting tool (34) into the apparatus, the shifting tool (34) including an engagement member releasably held in a radially retracted position; engaging the engagement member with the structure; applying a first biasing force to the shifting tool (34) in a first direction, thereby causing the engagement member to extend radially outward from its radially retracted position and applying a second biasing force to the shifting tool (34) in a second direction opposite to the first direction, thereby causing the structure to displace and operate the apparatus.