GB2405883A

GB2405883A - Wellhead cap with corrosion inhibitor

Info

Publication number: GB2405883A
Application number: GB0321503A
Authority: GB
Inventors: Timothy Mark Collins Handley
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-09-13
Filing date: 2003-09-13
Publication date: 2005-03-16
Also published as: GB0321503D0

Abstract

A protective cap 1 for a subsea wellhead 10 has an integral supply of corrosion inhibitor fluid. The fluid may be located in a bladder 2, and is released by a remote system such as a remotely operated vehicle or ROV. The fluid is preferably released by the removal of a release pin 6, which allows a weight 4 to apply force due to gravity on the bladder. The fluid is displaced through a flexible tube 7 into the interior of the wellhead. The fluid may be coloured and have a lower specific gravity than that of the surrounding seawater. It will therefore pass upwards and become captured under the apparatus on both the inside and outside surfaces of the subsea wellhead. A window 8 can then provide a visual indication that the fluid has been released.

Description

1 2405883 Corrosion Cap

Description

The invention relates to a protective cover for use with underwater oilfield or other equipment. The cover, commonly known as a corrosion cap, can be used to protect and inhibit the corrosion of an underwater wellhead or connector type part, and includes an integral supply of corrosion inhibition fluid, which can be displaced into a pre-determined location under the cover after installation.

Corrosion caps are widely used to protect seal surfaces, specific components and other important areas from damage and corrosion caused by underwater operations and the environmental conditions, however existing designs of corrosion cap are deployed from the surface without an integral supply of inhibiting fluid, and such fluid is later introduced either by a surface hose or via a plug-in connection to a remotely operated vehicle (ROV). This practice makes the deployment of a corrosion cap and inhibitor fluid a two-stage operation, first to install and then to fill, consuming vessel time and having an associated risk of failure.

An object of this invention is to provide an underwater corrosion cap that possesses integral inhibitor fluid that can be released by a simple diver or ROV operated mechanism, resulting in a quicker and more effective operation, which is also verifiable by a visual indication.

Accordingly, the invention provides a corrosion cap including an encompassing body, an integral reservoir of fluid, and a gravity or spring driven fluid displacement system.

Preferably the cap may sit upon the wellhead or connector part, or may be locked to it, and is operated by the removal of a release pin or other device that allows a weight, spring or float to displace the inhibitor fluid from its integral storage reservoir into the required location, and the successful displacement of the fluid into the required location shall be verifiable by visual indication system.

A preferred embodiment of the invention will now be described with reference to the accompanying FIGURE 1, and is described below.

The apparatus consists of a central housing (1) within which is located a bladder (2) containing corrosion protection fluid or fluid for other purposes, a spacer (3) and a weight (4). Attached to the housing is a cover (5), which encompasses, assists in the alignment of, and protects the subsea wellhead or connector part ( 10), and retains the fluid within the required area of the subsea wellhead or connector part.

The apparatus is first deployed by remotely operated vehicle (ROV), lift wire or diver to the subsea wellhead or connector part using handle (9), where it is aligned, located and fitted over the item to be protected.

After location, the release pin (6) is removed by ROV or diver, allowing the weight (4) to drop and apply force onto the bladder of fluid (2), and in doing so cause the bladder to displace its contents into the inverted flexible 'U' tube (7), which prevents the escape of the fluid within the bladder into the sea during handling and subsea deployment, and thence into the area between the body of the cap and the subsea wellhead or connector part.

The fluid, which may be coloured differently and will have a lower specific gravity than that of seawater, will therefore pass upwards and become captured under the apparatus on both the inside and outside surfaces of the subsea wellhead or connector part. A port, window or other device (8) will provide the user with a visual indication that the fluid has been correctly displaced.

Claims

Claims 1. An underwater corrosion cap for oilfield or other application

that is deployed from the surface with an integral supply of inhibitor/corrosion protection/preservation fluid, which has the fluid displaced from its reservoir by a remotely operated vehicle (ROY) or diver operated release system.
2. An underwater corrosion cap for oilfield or other application as claimed in Claim 1 where the method of fluid displacement consists of a weight, spring or float which exerts force upon a reservoir of fluid.
3. An underwater corrosion cap for oilfield or other application as claimed in Claim 1 where the successful transportation of fluid from the reservoir to the required area is verified by a visual indication.
4. An underwater corrosion cap as herein described above and illustrated in the accompanying drawings.