DOWNHOLE TOOL HAVING A SHOCK-ABSORBING SLEEVE

摘要

An apparatus having a shock-absorbing sleeve is disclosed. The apparatus comprises a housing, an axially moveable sleeve received in the housing and a sealed annular space having a fixed volume axially between the housing and the sleeve. A barrier axially moveable with the sleeve divides the annular space into a first and a second chambers. The first and second chambers are filled with uncompressible dampening fluid. One or more metering passages across the barrier fluidly connect the first and chambers. During the axial movement of the sleeve, the volume of the first chamber is reduced and that of the second chamber is increased, forcing the fluid in the first chamber to flow into the second chamber in a controlled manner to dampen the movement of the sleeve.

主权项

1. A downhole apparatus comprising:
a tubular housing along a tubing string; a sleeve located within the housing and axially moveable therein from a first position to a second position; and a first annular chamber radially intermediate the housing and the sleeve, said first annular chamber containing a first dampening fluid and being capable of controllably releasing the first dampening fluid under pressure; wherein when the sleeve moves from the first position to the second position, the first dampening fluid is pressurized and controllably released for controlling the speed of the sleeve movement.