LAUNCHING TOOL FOR RELEASING CEMENT PLUGS DOWNHOLE

摘要

A wiper plug release tool uses a first pump down plug that lands in the tool to pressurize an internal chamber to slide a sleeve that undermines a set of dogs to allow the lower wiper plug to be decoupled from support. The shifting of this sleeve cams a second set of dogs into an internal passage in the tool to act as a landing location for a second pump down plug. Landing the second pump down plug on the now extended dogs allows a net pressure to be applied to an upper piston which shifts a sleeve to release the support for the second wiper plug. The upper piston remains in pressure balance unless the second pump down plug can be landed on the dogs that only extended because the sleeve that released the lower wiper plug had shifted.