CN102677067A

CN102677067A - Replaceable cp anodes

Info

Publication number: CN102677067A
Application number: CN2012100824680A
Authority: CN
Inventors: R·贝尔
Original assignee: Vetco Gray LLC
Current assignee: Vetco Gray LLC
Priority date: 2011-03-17
Filing date: 2012-03-16
Publication date: 2012-09-19
Also published as: SG184667A1; EP2500512A1; EP2500512B1; US20120234692A1; MY153564A; AU2012201570A1; BR102012005980A2

Abstract

An anode (3) for cathodic protection of underwater-located equipment, comprises: a support body (10); sacrificial material (5) retained by the support body; and attachment means for releasably attaching the anode to the equipment.

Description

Removable CP anode

Technical field

The anode that the present invention relates to be used to be positioned at the galvanic protection of equipment under water provides the method for corrosion protection with being used for to being positioned under water equipment.The suitable equipment that is positioned under water can comprise and is used for the for example Jing Shu of subsea hydrocarbon fluid extraction facility.

Background technology

As well-known, wait to dispose underwater metal and be equipped with the risk that is corroded.In order to protect this equipment, normally near equipment, electric anode (being also referred to as " sacrificial anode ") is provided, thereby galvanic protection (CP) is provided equipment.Such anode comprises that the metal than equipment has the sacrificial metal material of bigger negative electricity electrochemical potential, makes that when being disposed, the anodic expendable material corrodes than the equipment metal more easily.At present, the prevailing metallic substance that is used as electric anodic expendable material comprises that the alloy of aluminium, magnesium and zinc, aluminum and zinc are suitable for using in the seabed.

Though all equipments that are deployed in the sea all receive this corrosive risk, exist be deployed in sea bed on the special problem that is associated of hydrocarbon fluid extraction facility (for example Jing Shu).These are more large-scale very expensive structures, usually need be in position for two more than ten years, and if corrode, possibly have great safety and environmental problem.

Typically, Jing Shu is provided with U-shaped aluminium electricity anode, and " supporting leg " of U-shaped is soldered on the tree, to guarantee good electric continuity.In Fig. 1, schematically shown this typical anode.As show, anode comprises aluminium block 1, metal supporting leg 2 extends from each end.In use, the free end with supporting leg 2 is welded on the Jing Shu.

Present convention is anodic bonding to be received on the tree framework (or other structure, manifold, template, fuel-displaced pedestal etc.) in the manufacturing stage.This provides good electric continuity so that it is worked efficiently for the CP system.

The amount of employed anodic quantity/aluminium changes according to the expectation field production life of well of tree.For the tree with long life-span, this means needs many anodes.For example, need eight anodes, then will set on the framework (or other structure) in the workshop receiving eight all anodic bondings if calculation result shows for vicennial field production life of well.This method can make tree by assembling thick and fast, so and fit into many anodes and can be difficulty, and can cause in addition anode must than expectation more near rapid wear zone.In addition, anodic arranges it is important---must consider anode position modestly, farthest reducing the danger of hydrogen embrittlement, and optimize galvanic protection.

Summary of the invention

The objective of the invention is to overcome these problems, and make it possible in the period of the working life of equipping, underwater kit (for example Jing Shu) carried out effective galvanic protection.Note that in following argumentation and in fact in claim, term " anode " is used for representing to comprise the project of expendable material, rather than expendable material itself.

Through utilizing removable electric anode to achieve this end.In a preferred embodiment, be suitable for inserting and remove these anodes by means of remote-operated vehicle (ROV).

According to a first aspect of the invention, a kind of anode that is used to be positioned at the galvanic protection of equipment under water is provided, has comprised:

Support body;

Expendable material by the support body fixing; And

Be used for releasedly anode being attached to the attached device on the equipment.

According to a second aspect of the invention, provide a kind of being used for the method for corrosion protection to be provided, may further comprise the steps being positioned under water equipment:

The anode of the galvanic protection that is provided for equipping, this anode comprises:

Support body, by the expendable material of support body fixing, and releasedly anode is attached to the attached device on the equipment; And

Anode is attached on the equipment.

Use advantage of the present invention

The invention provides the multiple advantage that is superior to prior art, include, but is not limited to:

I) the comparable conventional anode of each anode takies still less space in the tree;

Not to need many anodes ii), but need to use few relatively anode, can change these anodes on demand at the tree place;

Iii) consider top i) and ii), having more on the tree, the multilist space of planes can be used for other purpose;

Iv), there is possibility with quite long life-span so set owing to change anode on demand;

V) need not weld;

Vi) because anode is modular, so reduced the gross weight of tree;

Vii) need each anode be sent to tree from the water surface.Because use removable anode to mean to dispose through ROV one group of anode is sent to sea bed.ROV can pick up each anode successively then, with as needs with its placed in position.This through have can contain all equipments (for example, for example tree in regional area and manifold) only one dispose stroke and simplified action; And

Viii) can under the situation that does not have water surface operation, carry out all operations, can in adverse weather, carry out replacing through ROV.Can during for example the tree inspection is maked an inspection tour, carry out and change.

Description of drawings

To the present invention be described with reference to accompanying drawing now, wherein:

Fig. 1 has schematically shown the known aluminium electricity anode that is used in the use of submarine well tree place;

Fig. 2 has schematically shown anodic cross-sectional view according to an embodiment of the invention.

Embodiment

In Fig. 2, schematically shown first embodiment of the present invention.Here, shown just in time and to be deployed to the according to an embodiment of the invention anode 3 of well before setting 4 places.Anode 3 is designed to handled by ROV, but for clear, does not show ROV.

Anode 3 comprises the support body 10 of elongation, the quality of these support body 10 supportings and fixing expendable material 5.As show, expendable material 5 along circumferentially be molded in support body 10 around.Material 5 for example can comprise the material that is selected from the group of being made up of aluminium, zinc and magnesium, but can use other material.

An end of support body 10 comprises the parts that form convergent salient 6.This is shaped as so that make it possible to be frictionally engaged with well tree 4, and this is frictionally engaged and causes anode 3 in use to be retained on the tree place.More specifically, salient 6 is convergents, is arranged on well and sets in the holder 7 of shaping basically accordingly at 4 places with being retained on so that insert (" thrusting ").Convergent assists in ensuring that at anode 6 with between setting 4 and keeps electric continuity.

Holder 7 is the new devices that are particularly suited for fixing anode 3, and before anode was disposed, for example during manufacture, this device must be positioned at the tree place.Place the permission of setting on the framework to come the suitable position of disposing more simply through ROV holder 7.Substantially; Holder will be positioned in the place, outside of tree 4; But in other embodiments, holder can be placed in tree 4 the body, make anode 3 for example can from top (for example through the hole the top) or below (for example usage level track) be inserted in the holder in the body of tree.

Need friction to force the surface of salient 6 and holder 7 to merge, and guarantee that good electrical contact is arranged.In case the mode with friction engages, just working such as the lockout mechanism (not shown) that keeps latch piece is retained on anode 3 in the holder.Preferably, this lockout mechanism also can be actuated by ROV.As it will be appreciated by those skilled in the art that, steady brace can have the multiple design that does not simply more receive the Crustacean infringement, for example screw threaded arrangement or locking bar/pin, latch piece.

That kind as mentioned above, anode 3 are designed to handled by ROV.So anode comprises the grasping shank 8 friendly to ROV.As show, shank is installed on the support body at the far-end of salient 6.

Anode 3 also comprises the buoyancy that is used to make it possible to select anodic density, and in this case, this comprises the cavity that is filled with air 9 that is positioned at support body 10.Therefore, in fact, can think that support body 10 comprises the sealed hollow tube of the intensity with the environmental stress that is enough to withstand installed position.

The size of cavity and/or packing material preferably warp are selected so that anode 3 is neutral (neutral's) basically on buoyancy.This provides multiple advantage, particularly in order to the operation of installation/replacing anode 3 will more simply and more cost be effective.Under the degree of depth of an about km (being the degree of depth of pycnocline), the density of water can not change with the increase of the degree of depth significantly, but the degree of depth that depends on installation selects suitable anode buoyancy to can be preferably.As an alternatives, can make anode bigger than the density of the seawater of installation place, make that anode will sink to the seabed under the situation that accident discharges, to promote recovery.

In practice, suitable installation sequence can be and is described below:

A) on ROV emission framework, load anodes 3 many as needing, such emission framework is known in the prior art;

B) pick up the emission framework through ROV, and take it to need installation site;

C) through ROV independent anode 3 is placed corresponding well tree holder 7, between salient 6 and holder 7, to produce frictional fit;

D) engage positive lock mechanism, more firmly anode 3 is retained in the holder 7.

Certainly, after initial the installation, before can inserting new anode, the old anode of using up will remove through ROV.This need throw off positive lock mechanism through ROV.

Anode will be preferably included in making regular check in the process of use ROV (or driving mechanism) and Kamera.Thereby macroscopic test will determine when and must change.

Above-described embodiment only is exemplary, and other possibility within the scope of the invention and alternatives will be conspicuous to those skilled in the art.For example, for some devices, buoyancy cavity 9 can be filled with the material outside the air.For example, can be preferably, make support body more can withstand high environmental stress with solid material filled chamber 9, and can excessive deformation.

Alternatively, buoyancy can comprise the buoyancy tank that for example is attached on the support body.

Anode can be equipped with simple current/voltage monitoring device to detect the CP protection alternatively and when be reduced to and show the unacceptable level of needs replacing anodic.In this case, current/voltage monitoring device can be connected on the condition monitoring system of well.

Claims

1. anode that is used to be positioned at the galvanic protection of equipment under water comprises:

Support body;

Expendable material by said support body fixing; And

Releasedly said anode is attached to the attached device on the said equipment.

2. anode according to claim 1 is characterized in that, said attached device comprises and be used for the parts that are frictionally engaged with said equipment that said being frictionally engaged causes said anode in use to be retained on said equipment place.

3. anode according to claim 2 is characterized in that, parts comprise from the salient of said support body convergent, to insert and to be retained on the holder that is positioned at said equipment place.

4. according to each the described anode in the aforementioned claim, it is characterized in that said attached device comprises releasable positive lock mechanism.

5. according to each the described anode in the aforementioned claim, it is characterized in that said anode is included as by remote-operated vehicle and handles and specially designed shank.

6. anode according to claim 5 is characterized in that said shank is installed on the said support body.

7. an anode comprises the buoyancy that is used to make it possible to select anodic density.

8. anode according to claim 7 is characterized in that said buoyancy comprises the cavity that is positioned at said support body.

9. anode according to claim 8 is characterized in that said cavity is filled with air.

10. according to each the described anode in the aforementioned claim, it is characterized in that said expendable material comprises in the group of being made up of aluminium, zinc and magnesium.

11. each the described anode according in the aforementioned claim is characterized in that, the said equipment that is positioned under water comprises the submarine well tree.

12. one kind is used for to being positioned under water equipment the method for corrosion protection being provided, may further comprise the steps:

Be provided for the anode of the galvanic protection of said equipment, said anode comprises:

Support body, by the expendable material of said support body fixing, and be used for releasedly said anode being attached to the attached device on the said equipment; And

Said anode is attached on the said equipment.

13. method according to claim 12 is characterized in that, the manipulation through remote-operated vehicle is attached to said anode on the said equipment.

14. each the described method according in the claim 12 and 13 is characterized in that said anode is provided with the buoyancy that is used to make it possible to select said anodic density.

15. each the described method according in the claim 12 to 14 is characterized in that, the said equipment that is positioned under water comprises the submarine well tree.