Down hole 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 from a well bore during drilling operations by means of a single or multiple hydraulic jet pumps attached to a concentric string of casing. The DHDA includes a drill string and drill bit that passes through the jet pump assembly so that the power fluid is separated from the drilling or production fluid until after it has passed through the nozzle of the jet pump. The jet pump assembly is joined to a concentric casing string. The jet pump also contains a bladder element that inflates or expands to redirect the flow of the drilling and production fluid from the inner or return annulus into the jet pump assembly. The purpose of the jet pump assembly is to artificially lift and remove fluid thereby lowering the fluid level within a well bore to a point where the hydrostatic pressure exerted by the column of fluid near the bottom of the well is lower than the pore pressure of the formation being drilled thereby creating an under balanced condition.