Downhole apparatus and method

摘要

A downhole apparatus adapted to be run on a workstring in a well bore. The apparatus has a body including ports and a valve which is rotatable to open and close the ports to selectively allow fluid flow through the body between regions of a well bore above and below the apparatus. The valve is rotated via a gearbox and motor in the apparatus. A sealing arrangement between the valve and body is also described. A method of running the apparatus in a well bore and monitoring pressure above the apparatus in order to control opening and closing of the valve under predetermined conditions is presented.