GB2312910A - Underwater oil field apparatus - Google Patents

Underwater oil field apparatus Download PDF

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Publication number
GB2312910A
GB2312910A GB9709702A GB9709702A GB2312910A GB 2312910 A GB2312910 A GB 2312910A GB 9709702 A GB9709702 A GB 9709702A GB 9709702 A GB9709702 A GB 9709702A GB 2312910 A GB2312910 A GB 2312910A
Authority
GB
United Kingdom
Prior art keywords
equipment
installation
alignment device
magnetic alignment
oil field
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB9709702A
Other versions
GB9709702D0 (en
Inventor
Alan John Mcgovern
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ABB AS Norway
Original Assignee
Asea Brown Boveri AS
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from GBGB9609870.2A external-priority patent/GB9609870D0/en
Application filed by Asea Brown Boveri AS filed Critical Asea Brown Boveri AS
Priority to GB9709702A priority Critical patent/GB2312910A/en
Publication of GB9709702D0 publication Critical patent/GB9709702D0/en
Publication of GB2312910A publication Critical patent/GB2312910A/en
Withdrawn legal-status Critical Current

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Classifications

    • EFIXED CONSTRUCTIONS
    • E21EARTH OR ROCK DRILLING; MINING
    • E21BEARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B41/00Equipment or details not covered by groups E21B15/00 - E21B40/00
    • E21B41/06Work chambers for underwater operations, e.g. temporarily connected to well heads

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  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Geology (AREA)
  • Mining & Mineral Resources (AREA)
  • Physics & Mathematics (AREA)
  • Environmental & Geological Engineering (AREA)
  • Fluid Mechanics (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Earth Drilling (AREA)

Abstract

Underwater oil field equipment, such as control pod 1, is guided towards a landing base 2 by the interaction of magnets 5 and 6 so that sockets 3 and spigots 4 are aligned to effect connections between the pod 1 and the base 2.

Description

UNDERWA1 OIL FIELD D APPARATUS The present invention relates to underwater oil field apparatus and more particularly to the guiding of equipment, such as a control unit, onto a subsea installation such as a mounting or landing base. The invention is also applicable to other types of equipment, such as choke and valve assemblies, which are to be lowered to the sea bed for mounting on, or engagement with, a subsea installation already located on the sea bed.
For an underwater oil well to become operational, it is necessary to install at the well head an assembly, commonly known as a "Christmas tree", which combines equipment for monitoring and controlling the output flow from the well and typically comprises a large number of valves remotely controlled from an operating station on the surface. The surface operating station can be located on an oil rig which is connected to one or more Christmas trees by respective umbilical lines for conveying electrical and/or hydraulic energy and transmitting of electrical or optical signals to the valves for controlling the oil extraction.
In the case where the valves controlling the oil extraction are hydraulically actuated, they would typically comprise a hydraulic valve actuator connected to a supply of pressurised fluid via a control unit which comprises a control valve for regulating the flow of pressurised fluid between the umbilical line and each hydraulic valve actuator, each control valve being regulated by transmission of control signals from the surface operating station along the umbilical line.
It is well-known for the operation of an assembly of hydraulically actuated valves of a Christmas tree on a single well head to be effected by a control unit which is secured to the well head and is connected to the hydraulic valve actuators by flexible pipes.
This control unit, which is commonly known as a "pod", is a heavy and expensive apparatus which is specific to the configuration of a particular well head.
Typically, a control unit is lowered from a floating work barge or service vessel, onto its sub sea installation using remotely operated vehicles, remotely operated tooling and soft landing guide wires and latching pins located on the subsea installation. The weight of a control unit is typically 1.5 tonnes or more and requires substantial framing and counterweights on the installation to balance the loads on the well head tree.
The effects of equipment weight, weather, underwater currents, and the relative imprecision of remote working, typically 600 - 1000 m below the sea surface, create significant difficulties during alignment and installation. Existing alignment methods, some of which are described below, usually involve several stages of capture, each becoming progressively finer, to achieve the required accuracy.
The surface vessel would typically be equipped with a dynamic positioning system, so that it can maintain station above the sub sea installation within 1 or 2 metres. A remotely operated vehicle would be deployed to inspect and prepare the work site. Where necessary, the remotely operated vehicle would assist in establishing guide wires, lowered from the surface vessel, at anchorages on the subsea installation. With tension applied from above, the guide wires provide initial capture/alignment to the sub sea installation. The control unit would be loaded into a running tool which interfaces with the guide wires and provides further alignment with the sub sea installation.
With guide wires, the control unit/running tool assembly would usually be lowered on a lifting cable and would be negatively buoyant. With a single guide wire, or even without guide wires, the control unit/running tool assembly may have been designed to be neutrally buoyant so that a remotely operated vehicle can 'fly' it into position.
Final alignment and installation details vary according to equipment design, but three known arrangements are now described to illustrate the environment in which the present invention is applicable.
With the first known arrangement, a single tensioned guide wire extends from the surface vessel and is attached to the top of a cylindrical guide post secured to the subsea installation.
The control unit is carried by a running tool which has a tubular side member of sufficient internal diameter to engage the guide post. An inverted funnel is secured coaxially at the lower end ofthe tubular side member to align the tubular side member with the guide post.
Whilst the running tool is in the surface vessel, the guide wire is threaded through the tubular side member and is then appropriately tensioned. The running tool is then lowered on a lifting cable until the guide post enters the flared tube and then the lower end of the tubular side member. Further location of the running tool requires rotation about the guide post to capture a second alignment feature. This may be achieved by using a remotely operated vehicle to rotate the running tool about the vertical axis of the guide post until a second flared tube locates over a shorter second guide post, or by providing a cam and follower arrangement so that further lowering of the running tool results in the cam action rotating the running tool until the control unit is accurately aligned with the sub sea installation. In the final stages of lowering, the most accurate alignment features come into play, usually between the control unit or other equipment being installed and the sub sea installation, and usually in the form of cone-pointed precision pins engaging in precision bushings.
In a second known arrangement dual guide wires are used. Two guide posts of equal length are secured to the sub sea installation and provide anchorages for the guide wires thereby preventing rotational misalignment of the running tool as the second guide wire and the second guide post provide the second alignment feature.
Although the subsea installation is stationary, the surface vessel and its lifting cable move vertically on the waves and swell, presenting great difficulty in achieving a soft landing of the running tool and the carried equipment on the subsea installation. For this reason a "soft landing system" may be provided to cushion such impact.
A third known arrangement is known as the guide chute system. The guide chute is a relatively large fabrication in the form of a funnel cut off at an angle. Equipment being installed is contained entirely within the running tool in a predetermined orientation and this assembly is lowered on a lifting cable or, if neutrally buoyant, 'flown' by remotely operated vehicle. The assembly is guided by the remotely operated vehicle into the mouth of the funnel. The remotely operated vehicle is used to rotate the assembly which, in conjunction with further lowering, results in angular alignment being achieved by a fixed guide key inside the chute engaging a flared slot on the running tool Final alignment is achieved as described above.
The present invention is concerned with providing a simple system for guiding equipment into alignment with a subsea installation whereby the amount of expensive surface vessel time required to achieve alignment can be reduced.
According to one aspect of the invention the oil field apparatus comprises equipment to be mounted in a predetermined aligned position on an installation which in use will be located underwater, a magnetic alignment device having a first portion secured to the equipment and a second portion secured to the installation, the magnetic alignment device being operable to position one of said portions in a specific position relative to the other of said portions, and the first portion being positioned relative to the equipment and the second portion being positioned relative to the installation such that operation of the magnetic alignment device will move the equipment into said predetermined aligned position relative to the installation.
After assembly the oil field apparatus comprises equipment mounted on an underwater installation, a magnetic alignment device having a first portion secured to the equipment and a second portion secured to the installation, the magnetic alignment device positioning one said portions in a specific position relative to the other of said portions, and the first portion being positioned relative to the equipment and the second portion being positioned relative to the installation such that the equipment is in a predetermined aligned position relative to the underwater installation.
The first and second portions of the magnetic alignment device may be permanent magnets so that the magnetic alignment device is operable by moving the equipment towards the installation. Alternatively at least one of said portions may be an electromagnet, and the magnet alignment device is operable by energising the electromagnet when the equipment is adjacent the installation.
The first and second portions of the magnetic alignment device are preferably positioned such that operation ofthe magnetic alignment device will align an axis of the equipment with an axis of the installation. The first and second portions of the magnetic alignment device may also be positioned such that operation of the magnetic alignment device will rotate the equipment about their aligned axes to a predetermined angular position relative to the installation.
The equipment may include a remotely operated tool supporting a unit to be mounted on the installation.
According to another aspect of the invention a method of mounting equipment in a predetermined aligned position on an underwater installation comprises guiding the equipment into close proximity of the underwater installation, and using a magnetic field between the equipment and the underwater installation to move the equipment into the aligned position. The method may include using the magnetic field to move the equipment relative to the underwater installation until an axis of the equipment is aligned with an axis ofthe underwater installation. In this case the method may also include using the magnetic field to move the equipment about the aligned axes to a predetermined angular position relative to the underwater installation . In the case where the equipment comprises a remotely operated tool supporting a unit to be mounted on the installation, the method preferably includes detaching the remotely operated tool from the unit after the unit has been mounted in the predetermined aligned position. The use of magnetic alignment means enables one or both of the guide posts to be eliminated from the structure, thus making it smaller and lighter.
The invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a side elevation of equipment, in the form of a control pod, and associated underwater installation, in the form of a landing base, comprising one embodiment of the invention; Figure 2 is a plan view of the landing base of Figure 1; Figure 3 is a similar Figure 1 but illustrates a second embodiment of the invention utilising a remotely operated tool; and Figure 4 is a plan view of Figure 3.
With reference to Figures 1 and 2, a piece of equipment, in the form of a control pod 1, is to be lowered onto an underwater installation in the form of a landing base 2 which is already located on an unshown well head Christmas tree on the sea bed. The lowering is effected by means of an unshown cable secured to the control pod 1 by a fitting 10.
The control pod 1 has a series of sockets 3 adapted to cooperate, in known manner, with a series of spigots 4 on the landing base 2 when the control pod is in its landed position. The sockets 3 and spigots 4 form hydraulic, electrical or optical connections between the pod 1 and the base 2 but only interengage when the pod and the base are aligned both axially and angularly. The construction of the control pod 1, the landing base 2, the sockets 3 or the spigots 4 does not form part of the present invention and therefore will not be described in any more detail.
In order to steer the control pod 1 automatically to a position in which each socket 3 is aligned with the associated spigot 4 during the final approach of the control pod on to the landing base, a magnetic alignment device 5, 6 is provided on and between the control pod 1 and the landing base 2. This magnetic alignment device 5, 6 could take several forms but in this embodiment consists of first and second portions in the form of permanent magnets 5 and 6 permanently secured respectively to the control pod 1 and landing base 2. The polarities ofthe magnets 5 and 6 are arranged so that there is a mutual magnetic attraction between the two sets of magnets tending to pull the control pod 1 and landing base 2 together in the unique position in which each socket 3 is aligned with it associated spigot 4.
The control pod 1 is lowered from a surface control vessel over the landing base 2 on the cable, with or without the use of one or more guide wires, so that it is approximately in the correct position for landing on the base 2. As the pod 1 approaches the base 2, the magnetic fields of the magnets 5 and 6 come close enough to interact and cause movement of the pod 1 both laterally and rotationally relative to the base 2 until the sockets 3 and spigots 4 are correctly aligned for engagement. Thus, if the pod 1 is rotationally unaligned with the base 1, the action of the magnets 5 and 6 will cause the pod 1 to rotate about its suspension axis in order to effect the correct alignment of the sockets 3 and spigots 4. Whilst gravity is the dominant force bringing the pod 1 into engagement with the base 2, the magnets 5 and 6 also serve to draw the pod 1 onto the base 2.
By this means accurate positioning of the control pod 1 on the landing base 2 can be achieved without employing the earlier described relatively expensive methods and arrangements. For example, in certain circumstances the otherwise necessary use of an expensive remotely operated vehicle could be dispensed with. Furthermore, even where an a remotely operated vehicle would not normally be used, the relatively expensive and cumbersome guide arrangements for progressively guiding the control pod 1 on to the landing base 2 may be dispensed with.
In embodiment illustrated in Figures 3 and 4 those parts which correspond to the same parts in Figures 1 and 2 carry the same reference numerals. However, in this embodiment the control pod 1 is carried by a remotely operated tool 7 which is lowered on the end of a lift cable 8 and controlled via an umbilical control cable 9. The magnets 5 are carried on the underside of two downwardly extending arms 7a and 7b of the remotely operated tool 7.
The landing base 2 has diametrically opposed extensions 2a and 2b which carry the magnets 6 which are permanently fixed to the landing base as in the embodiment Figure 1, the magnets 5 being permanently fixed to the arms 7a and 7b of the remotely operated tool 7.
The control pod 1 it is carried by the remotely operated tool 7 which is lowered onto the landing base 2, the magnets 5 and 6 steering the remotely operated tool 7, and thus the control pod 1, into its final required accurate position with respect to the landing base 2 so that the sockets 3 and spigots 4 engage.
Instead of utilising permanent magnets 5 and 6 electromagnets could of course be used in either embodiment.

Claims (15)

1. Oil field apparatus comprising, equipment to be mounted in a predetermined aligned position on an installation which in use will be located underwater, a magnetic alignment device having a first portion secured to the equipment and a second portion secured to the installation, the magnetic alignment device being operable to position one of said portions in a specific position relative to the other of said portions, and the first portion being positioned relative to the equipment and the second portion being positioned relative to the installation such that operation of the magnetic alignment device will move the equipment into said predetermined aligned position relative to the installation.
2. Oil field apparatus, comprising, equipment mounted on an underwater installation, a magnetic alignment device having a first portion secured to the equipment and a second portion secured to the installation, the magnetic alignment device positioning one said portions in a specific position relative to the other of said portions, and the first portion being positioned relative to the equipment and the second portion being positioned relative to the installation such that the equipment is in a predetermined aligned position relative to the underwater installation.
3. Oil field apparatus, according to Claim 1 or 2, in which the first and second portions of the magnetic alignment device are permanent magnets, and the magnetic alignment device is operable by moving the equipment towards the installation.
4. Oil field apparatus, according to Claim 1 or 2, in which at least one of said portions is an electromagnet, and the magnetic alignment device is operable by energising the electromagnet when the equipment is adjacent the installation.
5. Oil field apparatus, according to any preceding claim, in which the first and second portions ofthe magnetic alignment device are positioned such that operation of the magnetic alignment device will align an axis of the equipment with an axis of the installation.
6. Oil field apparatus, according to Claim 5, in which the first and second portions of the magnetic alignment device are positioned such that operation of the magnetic alignment device will rotate the equipment about their aligned axes to a predetermined angular position relative to the installation..
7. Oil field apparatus, according to any preceding claim, in which the equipment includes a remotely operated tool supporting a unit to be mounted on the installation.
8. Oil field apparatus substantially as described herein with reference to Figures 1 and 2 ofthe accompanying drawings.
9. Oil field apparatus substantially as described herein with reference to Figures 3 and 4 of the accompanying drawings.
10. A method of mounting equipment in a predetermined aligned position on an underwater installation comprising, guiding the equipment into close proximity of the underwater installation, and using a magnetic field between the equipment and the underwater installation to move the equipment into the aligned position.
11. A method, as in Claim 10, comprising using the magnetic field to move the equipment relative to the underwater installation until an axis of the equipment is aligned with an axis of the underwater installation.
12. A method, as in Claim 11, comprising using the magnetic field to move the equipment about the aligned axes to a predetermined angular position relative to the underwater installation.
13. A method, as in any of Claims 10 to 12 and in the case where the equipment comprises a remotely operated tool supporting a unit to be mounted on the installation, including detaching the remotely operated tool from the unit after the unit has been mounted in the predetermined aligned position.
14. A method of mounting equipment in a predetermined aligned position on an underwater installation substantially as described herein with reference to Figures 1 and 2 of the accompanying drawings.
15. A method of mounting equipment is a predetermined aligned position on an underwater installation substantially as described herein with reference to Figures 3 and 4 of the accompanying drawings.
GB9709702A 1996-05-11 1997-05-12 Underwater oil field apparatus Withdrawn GB2312910A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB9709702A GB2312910A (en) 1996-05-11 1997-05-12 Underwater oil field apparatus

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GBGB9609870.2A GB9609870D0 (en) 1996-05-11 1996-05-11 Underwater oil field apparatus
GB9709702A GB2312910A (en) 1996-05-11 1997-05-12 Underwater oil field apparatus

Publications (2)

Publication Number Publication Date
GB9709702D0 GB9709702D0 (en) 1997-07-02
GB2312910A true GB2312910A (en) 1997-11-12

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Application Number Title Priority Date Filing Date
GB9709702A Withdrawn GB2312910A (en) 1996-05-11 1997-05-12 Underwater oil field apparatus

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000016297A1 (en) * 1998-09-11 2000-03-23 Comweld Group Pty. Ltd. A connector
US8525631B2 (en) 2010-11-01 2013-09-03 Nexans Underwater power connector system and use thereof
GB2595307A (en) * 2020-05-22 2021-11-24 Baker Hughes Energy Tech Uk Limited Magnetic connection system

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2086452A (en) * 1980-11-03 1982-05-12 Nl Industries Inc Underwater wellhead connector

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2086452A (en) * 1980-11-03 1982-05-12 Nl Industries Inc Underwater wellhead connector

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000016297A1 (en) * 1998-09-11 2000-03-23 Comweld Group Pty. Ltd. A connector
US8525631B2 (en) 2010-11-01 2013-09-03 Nexans Underwater power connector system and use thereof
GB2595307A (en) * 2020-05-22 2021-11-24 Baker Hughes Energy Tech Uk Limited Magnetic connection system
WO2021233577A1 (en) * 2020-05-22 2021-11-25 Ge Oil & Gas Uk Limited Magnetic connection system for connecting subsea components
GB2595307B (en) * 2020-05-22 2022-08-17 Baker Hughes Energy Tech Uk Limited Magnetic connection system

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Publication number Publication date
GB9709702D0 (en) 1997-07-02

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