Downhole drilling assembly with independent jet pump

摘要

A down hole drilling assembly (DHDA) is disclosed that induces artificial lift to remove the drilling and production fluid (101) from a well bore (160) by means of hydraulic jet pump(s) (322) attached to a concentric string of casing (150). The DHDA includes a drill string and bit (110) that pass through the jet pump assembly (310,320) so that a power fluid (100) is separated from the drilling or production fluid (101) until after it has passed through the nozzle (214) of the jet pump (322). The jet pump assembly (310,320) is joined to an inner concentric casing string (150). It contains a bladder element (316) that expands to redirect the flow of the drilling and production fluid (101) from an inner or return annulus (320) into the jet pump assembly (310,320). The jet pump assembly (310,320) creates an under balanced condition. <IMAGE>