FLUID PRESSURE PULSE GENERATOR FOR A DOWNHOLE TELEMETRY TOOL

摘要

A fluid pressure pulse generator apparatus for a downhole telemetry tool comprises a stator and a rotor. The stator has a stator body with a cylindrical central bore and at least one fluid flow chamber comprising a lateral opening and an uphole axial inlet. The rotor comprises a cylindrical rotor body at least partially rotatably seated within the central bore, a rotor head connected to an uphole end of the rotor body, and a fluid diverter comprising a fluid passage through the rotor body and at least one nozzle in the rotor head. At least one fluid passage has at least one fluid opening on an outside surface of the rotor body and an axial outlet at a downhole end of the rotor body. The at least one nozzle has an inlet end fluidly communicable with a drilling fluid and an outlet end in fluid communication with the at least one fluid opening. The cross-sectional flow area of the at least one nozzle increases from the inlet end to the outlet end such that the velocity of the drilling fluid slows while flowing from the inlet end to the outlet end of the at least one nozzle. The rotor can be rotated relative to the stator such that the fluid diverter is movable in and out of fluid communication with the at least one fluid flow chamber to create fluid pressure pulses in the drilling fluid flowing through the pulse generator.