Downhole cleanout tool

Abstract

A downhole tool for removing sand from a well bore has an elongated tubular member with four sections. A one-way valve is located between the upper first and second sections. A second one-way valve is located between the third and fourth sections, while a third one-way valve is in the fourth lower section. The second and third sections are formed into a piston assembly which when reciprocated moves fluid in the well bore from the fourth section to the first section in an incremental fashion. Each piston stroke traps portions of fluid at different locations along the tubular member because of the one-way construction of the valves, and moves that trapped portion incrementally upwardly within the device. Sand is accumulated in the second and fourth sections of the member, and the sand in the fourth section is prevented from backflowing into the piston section to foul the pump. The tubular member is constructed to allow for a full flowing flow in contrast to obstructed flow and a port in the lower portion of the tool enables relatively clean fluid from the well bore to be injected internally of the tool spaced from its bottom inlet to dilute the debris-laden fluid to further enable the debris-laden fluid to be more readily conducted through the tool pump portion without clogging the tool. A retrievable packer may be lowered with the device on a well string or wireline to isolate a portion of the well bore for accomplishing desired operations in the isolated well bore portion with the device.