DOWNHOLE APPARATUS AND METHOD

摘要

An apparatus for generating a fluid pressure pulse downhole includes an elongate tubular housing defining an internal fluid flow passage. A first device is coupled to the housing for controlling a flow of fluid along a first flow path that communicates with the internal fluid flow passage to generate a first fluid pressure pulse. A second device coupled to the housing for controlling a flow of fluid along a second flow path that communicates with the internal fluid flow passage to generate a second fluid pressure pulse. The first and second devices are releasably mounted in corresponding spaces defined in a wall of the housing, and the first and second devices each house a valve having a valve element and a valve seat. The valve being actuatable to control the flow of fluid along the first and second flow paths, respectively.