AU2018202244B2

AU2018202244B2 - Environmental protection

Info

Publication number: AU2018202244B2
Application number: AU2018202244A
Authority: AU
Inventors: Neil Douglas; Matthew Harris; Steve Simpson
Original assignee: Viper Innovations Ltd
Current assignee: Viper Innovations Ltd
Priority date: 2016-01-26
Filing date: 2018-03-29
Publication date: 2020-04-09
Anticipated expiration: 2037-01-24
Also published as: GB2593656B; GB2546893B; GB201700834D0; GB2593656A; AU2017200477A1; AU2017200477B2; AU2018202244A1; GB2546893A; GB202110079D0; GB201601385D0

Abstract

ENVIRONMENTAL PROTECTION 5 A distribution unit 10 is described comprising a housing 12 having a plurality of connectors 16, 18 to permit the connection of a plurality of lines or cables thereto such that, in use, the distribution unit 10 can be used in the distribution of inputs to a plurality of pieces of subsea equipment, the housing 12 including at least one socket 20 in which an active device 22 can be fitted to allow tests to be conducted and/or to permit 10 enhanced control, and a seal arrangement 36 whereby a seal can be formed between the active device 22 and the socket 20, the relative dimensions of the socket 20 and the active device 22 being such that only a small volume exists therebetween. Also described is an arrangement 50, 60 comprising a housing 52, 62, equipment located within the housing 52, 62, and a barrier fluid 54, 64, 66 located within the housing 52, 15 62 providing environmental protection to the equipment located within the housing 52,

Description

ENVIRONMENTAL PROTECTION

This invention relates to environmental protection of, for example, a distribution unit for use in subsea applications and/or the connections thereto. By way of example, the 5 distribution unit may be used in the distribution of electrical power and/or control signals to a plurality of subsea located pieces of equipment. However, the invention is not restricted in this regard and may alternatively or additionally be used in the distribution of chemicals, hydraulic or pneumatic pressures, optical signals or the like to subsea located equipment.

Subsea distribution units are in widespread use in distributing power and/or communication signals between an umbilical or cable connecting the distribution unit to a remote location and a plurality of subsea located pieces of equipment. In the event of a fault, it is typically necessary to disconnect a number of connections from the 15 distribution unit in order to allow tests to be conducted to identify the location of the fault. This is time consuming and inconvenient. Furthermore, the disconnection and reconnection operations can themselves generate faults. One object of the invention is to provide a distribution unit in which monitoring for faults can be undertaken in a more convenient manner, and/or in which enhanced control can be achieved.

One common cause of faults results from the connections to the distribution unit being exposed to a seawater environment. It is another object of the invention to provide a distribution unit in which the occurrence of such faults is reduced.

Whilst environmental protection for a distribution unit represents one application in which the invention may be used, the invention is also applicable to the protection of other subsea located equipment.

Any discussion of documents, acts, materials, devices, articles or the like which has 30 been included in the present specification is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present disclosure as it existed before the priority date of each of the appended claims.

Throughout this specification the word comprise, or variations such as comprises or comprising, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

According to one aspect of the present disclosure, there is provided an arrangement comprising a housing, equipment located within the housing, and a barrier fluid located within the housing, the equipment including at least one connector, wherein the connector is, in use, located within the barrier fluid so as to be separated from sea water by the barrier fluid, wherein the barrier fluid is of greater density than sea water, and wherein the housing is orientated such that the barrier fluid is retained therein, wherein the housing is in the form of a closed-bottom open top trough.

The equipment preferably includes a connector that, in use, is located within the barrier fluid. By way of example, the equipment may comprise a subsea distribution unit.

The barrier fluid is conveniently of greater density than sea water, and the housing is preferably orientated such that the barrier fluid is retained therein. By way of example, the housing may take the form of an open topped trough within which the barrier fluid is located, and into which at least a part of the equipment extends. The equipment may have a series of connectors associated therewith, the connectors being located within the housing so as to be immersed in the barrier fluid contained therein.

The housing may include a lid.

In an alternative arrangement, a barrier fluid of density lower than sea water may be used. By way of example, a gas such as nitrogen gas may be used as the barrier fluid. In such an arrangement, it may be desired to additionally provide a second barrier fluid of density greater than the first mentioned barrier fluid but lower than sea water, the second barrier fluid serving to separate the first mentioned barrier fluid from the sea water. By way of example, an oil such as silicon oil, may be used as the second barrier fluid. The equipment preferably has a series of connectors associated therewith, the connectors being located within the housing so as to be positioned within the barrier fluid contained therein.

2018202244 26 Feb 2020

The distribution unit may comprise a plurality of electrical connectors. Alternatively, or additionally, other forms of connector may be provided, for example to permit the distribution of chemicals, and/or to permit the distribution of hydraulic or pneumatic pressures, optical signals or the like.

According to another aspect of the present disclosure there is provided a distribution unit comprising a housing having a plurality of first connectors to permit the connection of second connectors associated with a plurality of lines or cables or devices thereto such that, in use, the distribution unit can be used in the distribution of inputs to a 10 plurality of pieces of subsea equipment, and a seal arrangement whereby a seal can be formed between at least one of the second connectors and a respective one of the first connectors, the relative dimensions of the first and second connectors being such that only a small volume exists therebetween.

According to yet another aspect of the present disclosure there is provided a distribution unit comprising a housing having a plurality of connectors to permit the connection of a plurality of lines or cables thereto such that, in use, the distribution unit can be used in the distribution of inputs to a plurality of pieces of subsea equipment, the housing including at least one socket in which an active device can be fitted to 20 allow tests to be conducted and/or to permit enhanced control, and a seal arrangement whereby a seal can be formed between the active device and the socket, the relative dimensions of the socket and the active device being such that only a small volume exists therebetween.

The active device is preferably removably fitted to the socket. When not fitted to the socket, a passive device is preferably fitted thereto.

The active device carries a seal arranged to cooperate with the socket to restrict sea water ingress to a connector part thereof. It will be appreciated that by restricting sea 30 water ingress, the likelihood of marine growth depositing upon the connector part is reduced. Likewise, by ensuring that only a small volume exists between the socket and the active device, accumulation of marine growth therebetween is restricted.

A barrier fluid is preferably located within the socket. Preferably, the barrier fluid is of greater density than sea water and the socket is orientated such that the barrier fluid is retained therein.

It will be appreciated that, in use, once the active device is introduced into the socket, the connector part thereof may be immersed in the barrier fluid, thereby protecting the connector part from any sea water that may be present within the socket.

The barrier fluid is preferably electrically non-conductive. It thus provides an additional electrical barrier. It is preferably selected to impede marine growth. As, upon removal of the active device, the barrier fluid may be exposed to the surrounding sea water, it is conveniently of an environmentally friendly material. For use over an extended period of time, the barrier fluid is preferably non-biodegradable.

The distribution unit may form part of an arrangement according to the first aspect.

Embodiments of the present disclosure will further be described, by way of example, with reference to the accompanying drawings, in which:

Figure 1 is a diagrammatic view of a distribution unit in accordance with an embodiment of the present disclosure;

Figures 2 and 2a are diagrammatic views illustrating part of the distribution unit of Figure 1, partly in section, with parts removed;

Figure 3 is a view illustrating an active device of the distribution unit of Figure 1;

Figures 4 and 5 are illustrations of a distribution unit arrangement in accordance with another embodiment of the present disclosure; and

Figures 6 and 7 are illustrations of a distribution unit arrangement in accordance with another embodiment of the present disclosure.

Referring firstly to Figures 1 to 3, a distribution unit 10 in accordance with an embodiment of the present disclosure is illustrated. The distribution unit 10 comprises

2018202244 26 Feb 2020 a housing 12 supported upon legs 14 intended for installation in a subsea location. The housing 12 includes a series of connectors including an input connector 16 whereby an umbilical or other cable can be connected to circuits located within the housing 12 and a series of output connectors 18 whereby cables can be connected to the distribution unit 10 to connect the distribution unit 10 to other pieces of subsea equipment. As is well known, the circuits within the distribution unit 10 are operable to allow power and/or control signals supplied via the umbilical or the like to be distributed to the various pieces of equipment connected to the distribution unit 10. As this function is well known, it is not described herein in further detail.

As shown, the housing 12 is formed with a series of sockets 20, each socket 20 being adapted to receive an active device in the form of a test device 22. As shown in Figures 2 and 2a, each socket 20 takes the form of a hollow, generally cylindrical housing 24 or stepped inner diameter. The housings 24 are mounted to the top of the 15 housing 12 of the distribution unit 10, and within a lower part of each housing 24 is located an electrical connector stub 26, the stub 26 being generally coaxial with the housing 24. The electrical connector stub 26 is electrically connected to the circuits of the distribution unit 10. A barrier fluid 40 is located within the socket 20, the barrier fluid 40 covering the connector stub 26 when the test device 22 is not fitted to the 20 socket 20, thus protecting the connector stub 26 against the build-up of marine growth.

The manner in which tests are undertaken using the test device 22 will be understood by a person skilled in the art, and so is not described herein in further detail.

Whilst this embodiment makes use of active devices in the form of test devices 22, it will be appreciated that some embodiments of the present disclosure are also applicable to arrangements in which the active devices perform other functions, for example enhanced control functions, communications functions or the like.

The test device 22 comprises a generally cylindrical body 28 of dimensions and shape such that it can be at least partially received within the housing 24. An upper end of the body 28 includes a handle 30 to aid manipulation thereof, and a key 32 projects from the outer surface of the body 28 for receipt within a corresponding key way formed in the socket 20 to ensure that the test device 22 can only be introduced into the socket 20 in a single angular orientation, thereby ensuring correct make up of electrical connections, in use.

Projecting from a lower part of the body 28 is a hollow connector part 34 adapted to fit over the connector stub 26 in such a manner as to make electrical contact therewith so as to electrically connect circuits within the test device 22 with circuits within the distribution unit 10.

A seal member 36 extends around the periphery of a part of the body 28, the seal member 36 cooperating, in use, with the inner surface of the socket 20 to restrict sea water ingress into the socket when the test device 22 is fitted thereto.

With the distribution unit 10 installed in a subsea location, and with umbilicals, cables or the like connected to the connectors 16, 18 as required, if it is desired to undertake tests on the various cables or the like or subsea located pieces of equipment, then test devices 22 may be fitted to the sockets 20. Depending upon the tests to be undertaken, it may be desired for the test device 22 to be fitted to a specific one of the sockets 20. When the test device 22 is fitted, it will be appreciated that the barrier fluid located within the socket 20 is displaced by the connector part 34, the barrier fluid 40 then substantially filling a volume defined between the test device 22 and the socket 20.

It will be appreciated that with the test device 22 fitted, tests may be undertaken on the distribution unit, and the cables and equipment connected thereto, to identify the nature and location of faults associated therewith. The nature of the tests may depend upon the functionality of the test device 22, and if desired, a number of interchangeable test devices may be provided to enable a range of tests to be undertaken.

With the test device 22 fitted, it will be appreciated that the barrier fluid 40 provides protection to the connectors associated with the test device 22 and socket 20, and the presence of the seal member 36 restricts sea water ingress into the socket 20 and the escape of barrier fluid therefrom. The barrier fluid 40 is preferably electrically inert, providing an additional electrical barrier for the connectors. In addition, by restricting sea water ingress, the risk of marine growth occurring within the socket 20 is reduced.

2018202244 26 Feb 2020

When no tests are required to be undertaken, the test device 22 may be removed. If desired, it may be replaced by a similarly shaped passive device 22a. The presence of the seal member 36 and barrier fluid 40 will again serve to protect the integrity of the connector stub 34.

Although the test devices 22 are removable/replaceable, and so lend themselves to temporary installation or reconfiguration, they may, if desired, be installed on a long term basis, and may be retrofitted to previously installed distribution units, if desired.

Whilst in the arrangement described hereinbefore a barrier fluid is provided in the socket, in some arrangements this fluid may be omitted, the presence of the seal member restricting sea water ingress into the space between the test device and the socket, in combination with the volume of the space between the test device and the socket being small, being sufficient to prevent marine growth.

Turning to Figures 4 and 5, a distribution unit arrangement 50 is illustrated, the arrangement comprising a distribution unit 10 of the general form described hereinbefore. In the arrangement of Figures 4 and 5, the positions of the connectors 16, 18 have been modified, but the present disclosure is not restricted in this regard 20 and could be employed using a distribution unit of the type shown in Figures 1 to 3.

The distribution unit arrangement 50 further comprises a housing in the form of a trough 52 within which the distribution unit 10 is located. The trough 52 is of closed bottomed form, and a barrier fluid 54 of density greater than sea water is located therein. The barrier fluid 54, like that used in the socket 20, is of electrically inert, non25 conductive form. It is preferably non-biodegradable so as to be suitable for use over an extended period of time, and is preferably environmentally friendly, thereby minimising any negative environmental impacts that may occur in the event that the material mixes with sea water and/or escapes from the trough 52. The trough 52 and depth of the barrier fluid 54 located therein are preferably such that the connectors 16, 18, and 30 components physically connected thereto, are completely immersed in the barrier fluid

54. The connections to the distribution unit 10 are thus separated from the sea water, and the risk of damage arising through contact with sea water, for example, water ingress to electrical components, the build-up of marine growth, or the like, is reduced. Electrical connections to the distribution unit 10 may be made and/or broken within the 35 barrier fluid 54.

As illustrated, the trough 52 is conveniently provided with a lid 56 that may be removed to gain access to the distribution unit 10, to allow removal or connection of components thereto. The design of the lid 56 is preferably such that the test devices 22 may be removed without the need to remove the lid 56. However, the present disclosure is not restricted in this regard. The primary purpose of the lid 56 is to avoid water currents from washing away the barrier fluid 54, and it may also serve to restrict access to the connectors 16, 18. It will be appreciated that in some arrangements, the lid 56 may be omitted, if desired.

It is envisaged that deployment of the arrangement shown in Figures 4 and 5 will involve positioning the distribution unit 10 and trough 52 in the desired location, introducing the barrier fluid 54 into the trough 52 and then establishing the desired electrical connections to the distribution unit 10, the connections being made within the barrier fluid 54. After establishing the electrical connections, the lid 56 may be fitted, and thereafter the test devices 22 (and/or passive devices 22a) fitted in position. Alternatively, the test devices 22 and/or passive devices 22a could be fitted in position prior to deployment of the distribution unit 10. To recover the arrangement to the surface, after removal of the lid 56 and breaking of the electrical connections, the barrier fluid 54 is drained into a suitable receptacle prior to lifting the distribution unit 10 and trough 52 to the surface.

Whilst the description hereinbefore is of a distribution unit arrangement 50 using a distribution unit 10 of substantially the form described with reference to Figures 1 to 3, it will be appreciated that some embodiments of the present disclosure are also applicable to arrangements in which other forms of distribution unit are used, for example distribution units 10 that do not have sockets 20 for fitting test devices 22 thereto.

Figures 6 and 7 illustrate an alternative distribution unit arrangement 60. In the arrangement 60, a housing 62 is provided over the distribution unit 10, the housing 62 being of open bottomed form, and closed at its top. For convenience, the housing 62 is hingedly connected to the distribution unit 10 (and is shown in its open condition in Figure 6), but this need not always be the case. The arrangement is adapted such that, once the required electrical connections have been made to the distribution unit

2018202244 26 Feb 2020 and the required test devices 22 and/or passive devices 22a fitted thereto, the housing 62 is secured in position with at least the connectors 16, 18 of the distribution unit 10 located within the housing 62. Once so positioned, a barrier fluid 64 in the form of a gas, such as nitrogen gas, of density less than sea water is introduced into the housing 62, displacing the sea water therefrom to a level such that the connectors 16, are not covered by the sea water, but rather are exposed to the barrier fluid 64.

The barrier fluid 64 should preferably be of a non-toxic material, and ideally should not be corrosive in the presence of water. As mentioned above, nitrogen gas may form a 10 suitable material for the barrier fluid 64. It may be introduced into the housing 62 from, for example, a pressurised gas canister mounted upon the housing 62.

Preferably, prior to introducing the barrier fluid 64 into the housing 62, a quantity of a second barrier fluid 66 of density greater than the first barrier fluid 64 but lower than 15 that of sea water is introduced into the housing 62. The second barrier fluid 66 will thus float upon the sea water within the housing 62. Upon the introduction of the first barrier fluid 64, the second barrier fluid 66 serves to separate the sea water from the first barrier fluid 64. This may be beneficial as, in the absence of the second barrier fluid, some sea water may evaporate into the first barrier fluid 64, and the combination of the 20 sea water and the first barrier fluid 64 may, depending upon the materials used, be corrosive. By isolating the first barrier fluid 64 from the sea water using the second barrier fluid 66, the risk of corrosion arising in this manner is reduced. The second barrier fluid 66 should preferably be non-hydroscopic, should be a dielectric, should be environmentally friendly, non-toxic and non-biodegradable. It may comprise, for 25 example, silicon oil.

Deployment of the arrangement may involve installing the distribution unit 10 and housing 62 in the desired location, moving the housing 62 to an open condition to allow access to the distribution unit 10 so that connections can be made thereto and test 30 devices 22 and/or passive devices 22a installed thereon. Subsequently, the housing is secured in position on the distribution unit 10. The second barrier fluid 66 is then released from a bladder 66a located within the housing 62, for example by way of an ROV operable valve or the like, so as to float upon the surface of the sea water within the housing 62, after which the first barrier fluid 64 is introduced into the housing 62, for 35 example via a bleed/fill valve 68 displacing the seawater from the upper part of the

2018202244 26 Feb 2020 housing 62. Conveniently, a window or float indicator or the like is provided to allow an operator to know when the desired quantity of sea water has been displaced, the connectors 16, 18 being located within the first barrier fluid 64 at that point.

Rather than supplying the first barrier fluid 64 from a cylinder or the like, it could be generated by causing a gas generating chemical reaction to occur beneath the housing 62. Similarly, rather than supplying the second barrier fluid from a bladder 66a located within the housing 62, other techniques are possible.

To recover the arrangement, the first barrier fluid 64 is vented from the housing 62 via the valve 68 to the surrounding sea water. The second barrier fluid 66 is then returned to the bladder 66a or another suitable receptacle. After venting or collection of the barrier fluids, the housing 62 can be released and moved to allow access to the distribution unit 10. The connections to the distribution unit 10 can be broken, and the arrangement then lifted to the surface.

By modifying the design of the housing 62, it is thought that both the barrier fluids 64,

66, or alternatively just the second barrier fluid 66, may be retained within the housing both when the housing 62 is in its in use position and when it is moved to the open 20 position in which access to the distribution unit 10 is permitted.

As with the arrangement shown in Figures 4 and 5, the arrangement of Figures 6 and 7 is advantageous in that corrosion of components of the distribution unit and associated connectors is reduced, the formation of marine growth is avoided, and the connectors are maintained in a clean condition. The barrier fluids serve to provide an additional electrical barrier, and cathodic protection demands are reduced.

Although the arrangement of Figures 6 and 7 uses a distribution unit 10 of the type described hereinbefore, it will be appreciated that the present disclosure is not restricted in this regard, and distribution units that do not include removable test devices may also be used without departing from the scope of the present disclosure.

In the description hereinbefore, for the most part the distribution unit is described as being used in the distribution of electrical power and/or signals. It will be appreciated, however, that the present disclosure is not restricted to such arrangements, and may

2018202244 26 Feb 2020 be employed in applications in which other connectors such as hydraulic or chemical conducting connectors are used, or in which optical fibres or the like are used. Indeed, the present disclosure may be employed in providing protection for devices other than distribution units.

Whilst specific embodiments are described hereinbefore, it will be appreciated that a wide range of modifications and alterations are possible without departing from the scope of the invention as defined by the appended claims.

Claims

CLAIMS:

1. An arrangement comprising a housing, equipment located within the housing, and a barrier fluid located within the housing, the equipment including at least one connector, wherein the connector is, in use, located within the barrier fluid so as to be separated from sea water by the barrier fluid, wherein the barrier fluid is of greater density than sea water, and wherein the housing is orientated such that the barrier fluid is retained therein, wherein the housing is in the form of a closed-bottom open top trough.
2. An arrangement according to claim 1, wherein the housing is provided with a removable lid.
3. An arrangement according to claim 1 or claim 2, wherein the barrier fluid is electrically non-conductive.
4. An arrangement according to any one of the preceding claims, wherein the barrier fluid is selected to impede marine growth.
5. An arrangement according to any one of the preceding claims, wherein the barrier fluid is selected to be of an environmentally friendly material.
6. An arrangement according to any one of the preceding claims, wherein the barrier fluid is non-biodegradable.
7. An arrangement according to any one of the preceding claims, wherein the equipment comprises a distribution unit comprising a plurality of connectors, and wherein the plurality of connectors are immersed, in use, in the barrier fluid.