Patent ID: 6065541
Filing Date: 2000-05-23
Classification: E21B

Abstract:
A cleaning device for a well bore which is adapted to be connected to a drill string for insertion into the well bore and through which cleaning fluid is pumped, comprising:an elongated outer sleeve having an axially extending through bore therein;means for connecting one end of the outer sleeve to the drill string;at least one port in the side wall of the outer sleeve, wherein each port is axially spaced along the outer sleeve;an elongated inner sleeve having an axially extending through bore therein and which is co-axial with and axially slidable within the outer sleeve;an annular seating collar located within the through bore of the inner sleeve;a plurality of ports in the side wall of the inner sleeve, wherein each port is axially spaced along the inner sleeve;pressure sensitive stop means for retaining the inner sleeve in place within the outer sleeve at predetermined axially spaced positions; andmeans for obstructing the annular seating collar and each port in the inner sleeve in a predetermined sequence such that when cleaning fluid is first connected to the cleaning device, the cleaning fluid passes through the inner sleeve and with the insertion of the first and each subsequent obstructing means, the inner sleeve is caused to move axially downwards relative to the outer sleeve onto each pressure sensitive stop means in turn, and in each of these positions one port in the inner sleeve is radially aligned with one port in the outer sleeve.