Wellhead annulus seal having a wickered surface

Abstract

An annular seal for use in a wellhead assembly has inner and outer legs that each extend in a direction that is generally parallel with an axis of the seal to define an annular space therebetween. Wickers are provided on an outer surface of the seal, so that when the seal is energized and the legs are urged radially apart from one another, the wickers engage with a mating surface of a downhole tubular. Embedding the wickers into the tubular creates a flow barrier across the interface between the seal and the tubular. The wickers deform the surface of the tubular, which creates a lock down force that opposes relative axial movement of the tubular.

Description

BACKGROUND[0001]1. Field of Invention[0002]The present disclosure relates in general to a wellhead assembly having a seal between coaxial members, where wickers are formed on a surface of the seal.[0003]2. Description of Prior Art[0004]Seals are typically inserted between inner and outer wellhead tubular members to contain internal well pressure. The inner wellhead member is generally a hanger for supporting either casing or tubing that extends into the well. Outer wellhead members are usually one of a wellhead housing, or can be a casing hanger when the inner member is a tubing hanger. A variety of seals located between the inner and outer wellhead members are known. Examples of known seals are elastomeric, metal, and combinations thereof and elastomeric rings. The seals may be set by a running tool, or they may be set in response to the weight of the string of casing or tubing. One type of metal-to-metal seal has seal body with inner and outer walls separated by a cylindrical slot...

AI Technical Summary

Benefits of technology

The patent is about a seal assembly for use in a wellhead assembly. The seal assembly includes an annular seal body made up of an elongate inner leg, an elongate outer leg, and an elongate slot between them. Wickers are provided on a curved surface of the seal body and selectively engage a tubular surface within the wellhead assembly. The seal assembly can also include a protective foam layer adhered to the wickers and an inlay that engages the wickers when the legs are in sealing contact with the tubulars. The seal assembly can be repeatedly inserted and urged apart for use in multiple wellhead assemblies. The technical effect of this invention is to provide a seal assembly that effectively seals the annulus between the inner and outer tubulars in a wellhead assembly, ensuring a tight seal that prevents leaks and other issues that can occur during well drilling and operation.

Problems solved by technology

If this force exceeds the retention capacity of the seal, the pressure controlling barrier between the inner and outer wellhead tubular members can be compromised.

Seal leakage can also occur due to a collection of debris on the wickers that interferes with energizing the seal and introduces a leak path across the wickers.

A large axial load between the seal and its mating surfaces due to thermal transients may also cause the seal to leak.

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