Dampered drop plug

摘要

A dampered drop plug drops down a bore of a drill string. The dampered drop plug includes a retainer configured to land on an upward facing shoulder of a tubular sleeve, and a plug releasably coupled to the retainer. The plug couples to the retainer while at a first pressure in the bore and decouples from the retainer at a second pressure in the bore. The dampered drop plug lands on the upward facing shoulder of a tubular sleeve and actuates a first function. The plug then releases from the retainer, and passes fluid through the retainer at a controlled flowrate. The plug then lands on a ball seat and actuates a second function.

主权项

1. A downhole tool for actuating a first and a second function while dampening a water hammer effect comprises:
a tubular mandrel having an inner passage and an upper end that secures to a string of conduit to receive a flow of fluid; an outer sleeve sealingly surrounding and axially movable relative to the mandrel, defining an annulus between the outer sleeve and the mandrel; a piston between the mandrel and the outer sleeve, defining upper and lower chambers in the annulus; an upper fluid port between the inner passage of the mandrel and the upper chamber; a lower fluid port between the inner passage of the mandrel and the lower chamber; the chambers having piston areas configured such that pressurized fluid flow from the inner passage simultaneously into both of the ports causes a net axial force on the outer sleeve to move the outer sleeve and an engaging member in a first axial direction to actuate the first function, and pressurized fluid flow through only the upper fluid port causes a net axial force on the outer sleeve to move the outer sleeve and the engaging member in a second axial direction to actuate the second function; a dampered drop plug having a plug releasably coupled to a retainer and configured to be dropped downhole from a surface and through the string, the dampered drop plug controlling a fluid flowrate through the inner passage following actuation of the second function; and a seat in the inner passage between the upper and lower fluid ports, configured so that when the dampered drop plug lands on the seat, the dampered drop plug interrupts communication of the pressurized fluid flow with the lower chamber, and allows communication of the pressurized fluid flow with the upper chamber, wherein the seat is affixed in the inner passage such that the seat defines an upward facing shoulder to receive a downward facing shoulder of the dampered drop plug, wherein the retainer has an annular upset extending from an upper portion thereof, the upset defining the downward facing shoulder configured to land on and abut the upward facing shoulder of the seat; the retainer further controls the fluid flowrate through the inner passage, and wherein the plug couples to the retainer while at a first pressure in the inner passage and decouples from the retainer at a second pressure in the inner passage.