A FLOW BYPASS SLEEVE FOR A FLUID PRESSURE PULSE GENERATOR OF A DOWNHOLE TELEMETRY TOOL

摘要

A flow bypass sleeve for a fluid pressure pulse generator of a downhole telemetry tool. The fluid pressure pulse generator comprising a stator having one or more flow channels or orifices through which drilling fluid flows and a rotor which rotates relative to the stator to move in and out of fluid communication with the flow channels or orifices to create fluid pressure pulses in the drilling fluid flowing through the fluid pressure pulse generator. The flow bypass sleeve is configured to attach to a drill collar which housing the telemetry tool and comprises a body with a bore therethrough which receives the fluid pressure pulse generator. The body includes at least one longitudinally extending bypass channel comprising a groove longitudinally extending along an internal surface of the body or an aperture longitudinally extending through the body. The bypass channel extends across at least a portion of both the stator and the rotor when the fluid pressure pulse generator is received in the flow bypass sleeve such that the drilling fluid flows along the bypass channel as well as flowing through the flow channels or orifices. The bypass channel diverts drilling fluid around the fluid pressure pulse generator and may be dimensioned to control the amount of drilling fluid being diverted.