Patent ID: 6241030
Filing Date: 2001-06-05
Classification: E21B

Abstract:
A jet pump section for use in a hydraulic underreamer comprising:a body having a longitudinal axis, a longitudinally extending pump section central bore with an upper end defining an inlet and a lower end defining an outlet, and a plurality of turn chambers circumferentially spaced around the pump section central bore, each turn chamber having at least one inlet passageway, in communication with the pump section central bore, and also having an outlet;a plurality of ejector nozzles corresponding to the plurality of turn chambers such that each ejector nozzle has an inlet in communication with a corresponding turn chamber outlet, each ejector nozzle also having an outlet;a plurality of venturis corresponding to the plurality of ejector nozzles such that each venturi has an inlet aligned with but spaced above a corresponding ejector nozzle outlet, each venturi also having an outlet;wherein the body further has defined therein a diffusion chamber surrounding the pump section central bore, the diffusion chamber having a plurality of inlets in respective communication with the venturi outlets and also having a substantially annular outlet adjacent to the inlet of the pump section central bore.