Patent Application
20150300111
The field of the invention is liner hangers and more particularly hangers that resist forces in opposed direction while locking a set while preventing premature actuation with a pressure balanced setting mechanism.
Liner hangers are used to support one string off another in subterranean locations. Some designs have slips that resist applied forces in opposed directions. This is typically accomplished by the orientation of surface wickers on slip elements. At times the liner hanger sets prematurely before reaching the desired location. In those events the release mechanism has to be applied and the hanger brought to the surface and redressed. Alternatively, the liner hanger can be resettable in response to hydraulic pressure and further feature a mechanical lock to keep the liner hanger from setting between movements as described in US 20130092369.
There are applications where premature setting is not desirable but also where once the hanger is set it is beneficial to be able to lock the set in a hanger that can resist forces in opposed directions. These and other features of the present invention will be more readily apparent to those skilled in the art from a review of the detailed description of the preferred embodiment and the associated drawings while recognizing that the full scope of the invention is to be determined from the appended claims.
A liner hanger features a pressure balanced setting sleeve system that applies no net force to the slips when internal pressure is raised in access ports associated with opposed actuation sleeves such that applied pressure results in opposed forces that cancel each other out. When one of the sleeves is isolated from tubing pressure and the other port to the other sleeve is pressurized, the bi-directional slips are extended and their extended position is locked with a lock ring to hold the set of the liner hanger against release.
Referring to
An upper cylindrical piston assembly 22 is formed by outer sleeve 24 and seals 26 and 28 that span upper ports 30 to define a chamber 32 that grows in volume in response to applied pressure in ports 30 when lower ports 34 (shown in
Lower cylindrical piston assembly 40 is formed by outer sleeve 42 and seals 44 and 46 that straddle openings 34 to define the chamber 48. Assemblies 22 and 40 generate equal and opposite forces when there is no ball 36 on seat 38 and internal pressure is applied in passage 50 that is in mandrel 12. The piston areas in chambers 32 and 48 are equal and opposite so that there is no net force applied to the slip assembly 14 when both ports 30 and 34 are in communication with each other in passage 50. However, once ports 34 are isolated from ports 30 in one of several ways, then pressure on ports 30 will put a net force on slip assembly 14 because the equal and opposite force from pressurizing chamber 48 will not be taking place. As a result the slip assembly 14 will be actuated to move the individual slips 18 up their respective ramps 20 to grip the surrounding tubular that is not shown and by so doing anchor the liner string that is not shown and that is suspended from mandrel 12.
The set locking feature is best seen in
Those skilled in the art will appreciate that the disclosed liner hanger will not accidentally set from applied pressure in the mandrel as some other intervention is required to separate ports 34 from ports 30 so that pressure at ports 30 will set the slips. Once set, the body lock ring 52 holds the set so that release is not possible. The slips are bidirectional in resisting force from opposed directions. Preventing the slips from moving until a desired time can be alternatively accomplished with a mechanical lock on the actuator for the slips that is selectively defeated with applied pressure where, for example, a rupture disc is broken that leads to a piston whose movement sets the slips. Alternatively a predetermined pattern of mandrel movement that is induced with string manipulation or pressure cycles with a j-slot mechanism to defeat a lock can also be used. The process of defeating the lock can also be integrated with ramping out the slips in a single fluid motion. The lock in the set position can be accomplished in alternative ways such as letting a snap ring snap into a groove or inserting a dog into adjacent parts with a support to keep such parts from moving relatively when the slips are set.
The above description is illustrative of the preferred embodiment and many modifications may be made by those skilled in the art without departing from the invention whose scope is to be determined from the literal and equivalent scope of the claims below:
