GB2582542A

GB2582542A - Connector and associated methods

Info

Publication number: GB2582542A
Application number: GB1903356.2A
Authority: GB
Inventors: Slater Robin
Original assignee: Aker Solutions IP Ltd
Current assignee: Aker Solutions IP Ltd
Priority date: 2019-03-12
Filing date: 2019-03-12
Publication date: 2020-09-30
Anticipated expiration: 2039-03-12
Also published as: WO2020183178A1; EP3938617A1; GB201903356D0; GB2582542B

Abstract

A resealing, pressure balancing subsea connector 12 comprises an internal portion comprising a first fluid, and a seal 13 where the seal opens at a differential pressure threshold across the seal 13, the pressure differential threshold being lower than that corresponding to atmospheric internal pressure in the internal portion and an external pressure at the exterior of the connector 12 when deployed. The connector 12 may be waterproof rated as IPx8 or worse and used at a greater depth or pressure than it is rated for. The first fluid may be pressured by external pressure during descent. The first fluid may be insulative. The connector 12 may be in an apparatus which may comprise a subsea control module 10 deployed beyond the waterproofness rating. The apparatus may comprise a housing 11 acting as a fluid chamber, pressurised by a second fluid such as water. The method for constructing and deploying the connector 12 is presented. There may be a deployment beyond a depth of 20 metres. The connector 12 may be mated, sealed and pressurised at the surface before deployment.

Description

CONNECTOR AND ASSOCIATED METHODS

TECHNICAL FIELD

This disclosure concerns a connector, such as an underwater connector for connection in an electrical line subsea; and associated methods, such as methods of connection and/or deploying connectors.

BACKGROUND

Waterproof connectors allow two or more lines to have an underwater connection -for example to connect a first line or component to a second line or component. Depending on the particular connector, connections can be made underwater; or made at surface and then submerged. "Dry-mate" connectors allow connections to be made at surface, in air, with the completed connector then being suitable for submerging in water. "Wet-mate" connectors even allow the connections to be completed underwater, such as by coupling two parts of the connector (e.g. male & female) when the two parts are already separately submerged underwater.

Waterproof connectors typically have seals to prevent water ingress into the internal of the connector. The seals are often compression seals, such as 0-rings, gaskets, or the like. Different waterproof connectors are able to withstand different exposures, such as different pressures or different lengths of time of exposure to pressure. Waterproof connectors are often categorised or rated to define or quantify how "waterproof" or "watertight" the connectors are. An "IP" Code ("International Protection", or "Ingress Protection") is often used to indicate a level of waterproofing. The IP code has a first digit to indicate a level of protection against ingress of foreign bodies or particulate matter; and a second digit to indicate a level of protection against water ingress. Sometimes a third, and even fourth, digit or letter is suffixed, such as to indicate a particular material or application (e.g. IP68M). The IP code is published by the International Electrotechnical Commission (IEC), with the equivalent European standard being EN 60529. Similarly, the National Electrical Manufacturers Association defines NEMA enclosure types in NEMA standard number 250. All standards and external references herein are as published at the effective filing date of this application.

In the oil/gas industry, wellheads are typically at least partly controlled using Subsea Control Modules ("SCMs"), such as where an SCM controls a Xmas Tree ("XMT") associated with a production wellhead. The SCM provides well control functions, particularly during the production phase of subsea oil/gas production. The SCM contains electronics for performing a variety of functions, often including: processing communications signals, conditioning electrical power supplies, providing status information; and distributing signals and power to/from control valves, pressure/temperature sensors, and the like.

Safety or industry standards stipulate particular requirements for connectors. For example, API 17F, as defined at the priority date of this application by the American Petroleum Institute, stipulates that connections must continue to operate when surrounded by seawater.

The subject matter of at least some examples of the present disclosure may be directed to overcoming, or at least reducing the effects of, one or more of the problems of the prior art, such as may be described above.

SUMMARY

According to a first aspect there is provided a connector. The connector may comprise an electrical connector for an electrical connection. The connector may comprise an underwater or subsea connector. The connector may comprise a subsea electrical connector for providing a subsea electrical connection.

The connector may comprise an internal portion. The internal portion may comprise an internal volume. The internal volume may comprise a void. The internal portion may comprise a sealed internal portion.

The internal portion may comprise a first fluid. The first fluid may be for protecting the connector from passage or ingress of a second fluid from an exterior of the connector into the internal portion.

The first fluid may comprise a liquid. The first fluid may comprise an inert fluid. The first fluid may comprise an electrically-inert fluid. The first fluid may comprise a nonconductive fluid. The first fluid may comprise an insulating fluid. The first fluid may comprise a dielectric fluid. The first fluid may comprise an oil. The oil may comprise a transformer oil. The first fluid may comprise a different fluid from the second fluid.

The connector may be configured for the internal portion to be or become filled with the first fluid during deployment, such as when the connector is submerging or sinking or descending to the location of deployed use. In use, the connector may become filled with the first fluid by a descent of the connector towards a depth of the location of deployed use.

The first fluid may comprise a pressurised fluid. For example, the first fluid may comprise a pressure corresponding to a depth of deployment, or intended deployment, of the connector. The first fluid may be pressurised to balance a pressure differential between the internal portion and the exterior of the connector. The first fluid in the internal portion may be or become pressurised during deployment of the connector, such as by sinking to the connector to a deployment depth or location. The first fluid may enter the connector during hyperbaric testing, such as part of a control module delivery process. After hyperbaric testing the first fluid inside the connector may return to atmospheric pressure. Accordingly, some fluid may be expelled from the connector back into the control module housing. Thereafter subsequent pressurisation/depressurisation cycles may result in only a small amount of the first fluid entering or leaving the connector through differential pressure across the connector seal/s.

The connector may comprise a seal. The seal may be for sealing the internal portion from the exterior of the connector. The seal may be configured to remain seated until a pressure threshold is reached. The pressure threshold may be a pressure differential across the seal, such as between the internal portion of the connector and the exterior of the connector. The pressure differential may be associated with a depth. For example, the seal may open at a pressure differential corresponding to a particular depth of water at the exterior of the connector and atmospheric pressure in the internal portion of the connector.

The first fluid may balance a pressure differential across the seal. The first fluid in the internal portion may be at a pressure similar to an external pressure at the exterior of the connector, at least when the connector is deployed at the depth or location of use.

The connector may be rated to a maximum depth less than an intended depth of deployment. The connector may be configured to remain sealed until a pressure threshold is reached. The pressure threshold may be a pressure differential across the seal, such as between an internal of the connector and an exterior of the connector. The pressure differential may be associated with a depth. For example, the connector may be configured to remain sealed until the connector is lowered to a depth corresponding to the pressure threshold.

The seal may be rated to a maximum depth less than the intended depth of deployment of the connector. The seal may be configured to open at a pressure lower than a pressure at a location of deployed use of the connector. The seal may be configured to open at a pressure differential less than that corresponding to the ambient pressure at the location of deployed use of the connector and an internal pressure within the internal portion of atmospheric pressure. The pressure differential threshold may be less than a difference between atmospheric pressure and the ambient pressure at the location of deployed use.

The first fluid comprised in the internal portion of the connector may be pressurised. The first fluid may be pressurised to a pressure corresponding to an external pressure at the exterior of the connector at the location of deployed use of the connector. The first fluid may be pressurised to the corresponding pressure such that the pressure differential across the seal between the first fluid pressure in the internal portion and the external pressure is less than the threshold to open the seal. The first fluid may be pressurised such that a pressure difference between the first fluid pressure in the internal portion and a pressure of an ambient fluid at the location of deployed use is less than the pressure differential threshold for opening the seal.

The connector may be deployed, in use, at a depth greater than that corresponding to the waterproofness rating. The connector may be deployed at a depth and/or pressure greater than indicated in a rating for the connector. For example, the connector may be rated to a depth of 50 meters or less; and deployed at a depth of more than 50 meters.

The connector may comprise a rated connector. For example, the connector may comprise a water ingress rating selected from: IPX5, IPX6, IPX7, IPX8, I PX9, IPX9K, or the like. The connector may be rated to a waterproofness rating corresponding to I Px8 or poorer. The location of deployed use of the connector may correspond to a depth greater than the waterproofness rating. The location of deployed use of the connector corresponds to a pressure greater than the waterproofness rating. The connector may be configured for and/or rated to a maximum water exposure. The maximum water exposure may comprise one or more of: maximum depth, maximum pressure, maximum duration of time; type of water; temperature. In use, the connector may be exposed beyond the maximum rated water exposure.

The pressure threshold may be at or beyond a rating of the connector and/or seal. For example, the connector may be rated for use to a maximum pressure corresponding to a maximum depth of use. In at least some examples, the seal will remain seated to a pressure greater than the maximum rated pressure. For example, the seal of a connector rated for use to a maximum depth of water of 50 meters may remain seated until a pressure threshold is reached in a water depth of 70 meters, such as due to a margin of error or safety margin (e.g. to ensure compliance with rating).

The connector may be rated for use at a maximum depth of 300 meters or less; optionally 200 meters or less; optionally 100 meters or less; optionally 50 meters or less; optionally 20 meters or less; optionally 10 meters or less. For example, the connector may be rated for use at a maximum depth of 20 meters. The connector may be rated for use at a maximum pressure of 30 bar or less; optionally 20 bar or less; optionally 10 bar or less; optionally 5 bar or less; optionally 2 bar or less; optionally 1 bar or less. For example, the connector may be rated for use at a maximum depth of 20 meters and/or a maximum pressure of 2 bar.

The connector may be configured for use at a pressure and/or depth significantly or substantially greater than indicated by the (maximum) rating. The connector may be configured for use at a pressure and/or depth a factor or even order of magnitude greater than indicated by the (maximum) rating. Particularly when the internal portion comprises the first fluid, the connector may be configured for use at a depth greater than 10 meters; optionally 20 meters; optionally 50 meters; optionally 100 meters; optionally 200 meters; optionally 300 meters. For example, the connector may be configured for use at a depth of 300 meters or more. The connector may be configured for use at a pressure of more than 1 bar; optionally more than 2 bar; optionally more than 5 bar; optionally more than 10 bar; optionally more than 20 bar; optionally more than 30 bar. For example, the connector may be configured for use at a depth of more than 20 meters and/or more than a pressure of 2 bar.

In use, the connector may be at a depth greater than 10 meters; optionally 20 meters; optionally 50 meters; optionally 100 meters; optionally 200 meters; optionally 300 meters.

In at least some examples, the connector may be rated for use at a maximum depth of 50 meters or less; and configured for use, when filled with the first fluid, for deployment at a depth of 300 meters or more.

The internal portion may be filled with the first fluid. Filling may comprise at least partially filling. Prior to becoming filled with the first fluid, the connector's internal portion may be at atmospheric pressure. For example, prior to being filled with a liquid first fluid, the internal portion may comprise air. Filling the internal portion with the first fluid may compress and/or expel a previous fluid, such as air, in or from the internal portion. The internal portion may be filled with the first fluid via the seal, when the seal is open. The seal may be opened to fill the internal portion by a pressure differential across the seal.

The seal may be configured to open at a first pressure threshold when the pressure at the exterior of the connector is greater than pressure in the internal portion of the connector. The seal may be configured to open at a second pressure threshold when the pressure at the exterior of the connector is greater than the pressure in the internal portion of the connector. The first and second pressure thresholds may be the same. Alternatively, the first and second pressure thresholds may be different. For example, the second pressure threshold may be greater than the first pressure threshold (or vice versa).

The connector may comprise a plurality of seals. The connector's rating may be determined by the weaker or weakest, seal, such as the seal that opens at a lower or lowest pressure or pressure differential threshold. The internal portion may be filled with the first fluid via the weaker or weakest seal.

The internal portion may comprise a connection. The connection may comprise a join or link. The connection may be for signal/s; and/or power; and/or communication/s. The connection may comprise an electrical connection. Additionally, or alternatively, the connection may comprise an optical connection. For example, the connection may be for transmitting an electrical signal between a pair of devices. The connection may comprise a bridge electrically and/or mechanically linking a first longitudinal member to a second longitudinal member. The longitudinal member/s may comprise a tube and/or a wire/s, such as a pair of electrical cables or wires. The connector may comprise a plurality of connections, such as a plurality of bridge connections connecting a plurality of longitudinal members. The connector may comprise a "dry-mate" connector.

According to a further aspect, there is provided an apparatus comprising the connector of any other aspect, example, embodiment or claim. The apparatus may comprise a subsea apparatus for the oil/gas industry. The apparatus may comprise a subsea control module ("SCM"). The apparatus may comprise a subsea electronics module ("SEM").

The apparatus may comprise an enclosed volume. The enclosed volume may define a cavity. The enclosed volume may comprise the first fluid. For example, the enclosed volume may comprise an insulating liquid. The apparatus may be sealed to separate the enclosed volume from the second fluid outside the apparatus.

The apparatus may be configured and/or rated to operate at a depth and/or a pressure greater than that for which the connector is rated. For example, the apparatus may be for operation at a greater depth than a maximum depth for which the connector is rated.

The apparatus may be configured to balance pressure. The apparatus may be configured to match a pressure within the apparatus to a pressure outside the apparatus. For example, the apparatus may be configured to match the pressure of the first fluid within the enclosed volume of the apparatus with the second fluid outside the apparatus. In at least some examples, the apparatus is configured to actively balance the pressure within the apparatus as the pressure outside the apparatus varies. The apparatus may be configured to increase the pressure of the first fluid in the enclosed volume as the pressure of the second fluid outside the apparatus increases, such as when the apparatus moves to a greater depth in the second fluid. The second fluid may comprise the ambient fluid, the ambient fluid defining the ambient pressure outside the apparatus at the location of deployed use.

The apparatus may comprise a pressure compensator. The pressure compensator may be configured to pressurise an interior of the apparatus in accordance with a pressure external to the apparatus, such as the ambient pressure. The pressure compensator may be configured to pressurise the first fluid in the enclosed volume. The pressure compensator may comprise a pressurisation member. The pressure compensator may comprise one or more membrane/s, bladder/s, resilient member/s or the like.

The apparatus may be configured to protect the connector. The apparatus may be configured to protect the connector from contact with the second fluid. The apparatus may be configured to protect the connector in the event of ingress and/or a presence of an undesirable fluid, such as the second fluid, in or into the enclosed volume of the apparatus. For example, the apparatus may be configured to protect the connector in the event of a failure of the pressure compensator, such as a failure or rupture of a membrane or bladder. The apparatus may be configured to prevent the ingress of the second fluid into the connector in the event of ingress and/or a presence of the undesirable fluid, such as the second fluid, in or into the enclosed volume of the apparatus. The apparatus may be configured to protect the connector from ingress of the second fluid by filling the connector with the first fluid at the pressure correspondent to the ambient pressure of the second fluid. The connector may be configured to prevent ingress of the second fluid into the connector when the connector is exposed to the second fluid at its exterior. The connector may be resilient to being surrounded by seawater. The apparatus may be configured to protect the connector in conformance with an industry or safety requirement. For example, the apparatus may be configured to protect the connector in conformance with API 17, such as 17F and/or 17H, as defined at the priority date of this application by the American Petroleum, ensuring that the connector can continue to operate when the connector is surrounded by seawater. The connector may be configured to comply with section 6.4.3 of API 17H. The connector may be suitable for direct exposure to a subsea environment. The apparatus may provide a double barrier against seawater-induced malfunctions. The apparatus may be configured such that leakage in a hydraulic part of the apparatus shall not affect the integrity of the electric system.

The connector may be for a SEM. For example, the Apparatus may comprise a SEM within or attached to the enclosed volume. The connector may connect the SEM to other device/s, such as an actuator (e.g. solenoid or the like).

The apparatus may comprise a plurality of connectors. The apparatus may comprise a plurality of devices. The apparatus may comprise a plurality of SEMs and/or actuator/s. In at least some examples, the plurality of connectors may connect the SEM to the plurality of devices.

According to a further aspect, there is provided a method of connection. The method may comprise providing the connector of any other example, embodiment, claim or aspect. The method may comprise a method of subsea or underwater connection. The method may comprise providing the connection in the apparatus of any other aspect, example, embodiment or claim.

The method may comprise assembling the connector. The method may comprise assembling the connector at surface. The method may comprise assembling the connector in atmospheric pressure. The method may comprise making or mating the connection under atmospheric pressure, such as at surface. For example, the method may comprise connecting a first device to a second device via the connector prior to submersion of the apparatus in the second fluid. The method may comprise sealing the internal portion prior to submersion in the second fluid. The connection may comprise a join or link. The connection may be for signal/s; and/or power; and/or communication/s. for example, the connection may be for transmitting a signal between a pair of devices. The connection may comprise a bridge electrically and/or mechanically linking a first longitudinal member to a second longitudinal member. The longitudinal member/s may comprise a tube and/or a wire/s, such as a pair of electrical cables or wire/s. The connector may comprise a plurality of connections. The method may comprise connecting the SEM to the device/s.

The method may comprise filling the internal portion of the connector with the first fluid.

The method may comprise expelling and/or compressing a fluid previously in the internal portion, such as air. The previous fluid may be or have been present in the internal portion at atmospheric pressure, such as when/during assembly and/or connection of the connector. Filling the internal portion with the first fluid may comprise partially-filling the internal volume with fluid, such as where not all of the previous fluid is expelled. For example, a pocket/s of air may remain in the internal portion, compressed by the first fluid. Alternatively, the internal portion may be completely filled with the first fluid, such as where all of the previous fluid is expelled (e.g. through a same and/or different seal) when the first fluid enters the internal portion.

The method may comprise filling the connector with the first fluid during hyperbaric testing, such as part of a control module delivery process. The method may comprise returning the connector and fluid therein to atmospheric pressure, after hyperbaric testing. Accordingly, the method may comprise expelling some of the first fluid from the connector back into the enclosed volume of the apparatus (e.g. cavity of SCM housing).

The method may comprise subsequent pressurisation/depressurisation cycles, wherein each cycle may result in only a small amount of the first fluid entering or leaving the connector through differential pressure across the connector seal/s.

The method may comprise pressuring a fluid external to the connector to or beyond a pressure threshold. The fluid may comprise the first fluid. The pressure threshold may comprise a pressure differential threshold. The pressure threshold may comprise a first pressure threshold. For example, the method may comprise opening the seal at a first pressure threshold when the pressure at the exterior of the connector is greater than pressure in the internal portion of the connector. The method may comprise opening the seal at a second pressure threshold when the pressure in the internal portion of the connector is greater than the pressure at the exterior of the connector. The first and second pressure thresholds may be the same. Alternatively, the first and second pressure thresholds may be different. For example, the second pressure threshold may be greater than the first pressure threshold (or vice versa).

The method may comprise filling the internal portion with the first fluid via the seal, when the seal is open. The method may comprise opening the seal to fill the internal portion by a pressure differential across the seal. The method may comprise pressurising the first fluid external to the internal portion in order to generate the pressure differential across the seal, to open the seal to allow the internal portion to receive the first fluid under pressure from the exterior of the connector.

The method may comprise opening the seal at a pressure lower than a pressure at a location of deployed use of the connector. The method may comprise opening the seal by provision of a pressure differential across the seal.

The method may comprise positioning the connector within a fluid chamber of an apparatus. The fluid chamber may comprise a cavity, such as a cavity of a housing. The method may comprise filling the fluid chamber with a fluid. The fluid may comprise the first fluid. The method may comprise filling the internal portion of the connector with the first fluid from the fluid chamber of the apparatus. The method may comprise providing the connector with the first fluid in the internal portion within the same, first, fluid in the fluid chamber of the apparatus.

The method may comprise pulling or drawing vacuum in the apparatus. For example, the method may comprise drawing a small vacuum, such as around 0.2 bar, prior to and during the filling of the fluid chamber with the first fluid, such as to extract air from the apparatus when being filled with the first fluid. The method may comprise breaking the the seal on the connector by drawing the vacuum. The method may comprise extracting air from the connector, such as by breaking the seal by drawing the vacuum in the fluid chamber.

The method may comprise deploying the connector at a location that corresponds to a pressure greater than a rating of the connector, such as an indicated maximum pressure rating of the connector. The method may comprise deploying the connector at a depth greater than that corresponding to a waterproofness rating. The method may comprise using a connector with a waterproofness rating corresponding to IPx8 or poorer in a location with a pressure that exceeds the waterproofness rating. For example, the method may comprise deploying an IPx8 connector in a depth of water, or at a pressure, that is in excess or beyond that indicated as a maximum for the IPx8 connector (e.g. by the industry standards and/or a manufacturer or supplier of the connector).

The method may comprise filling the internal portion with the first fluid by deploying the connector to the location of use. The method may comprise filling the internal portion with the first fluid by pressurising the first fluid in the fluid chamber in which the connector is positioned. The method may comprise pressurising the first fluid in the fluid chamber external to the connector by lowering the apparatus in a second fluid, such as in a body of water. The method may comprise pressurising the first fluid in the fluid chamber to generate a pressure differential across the seal to cause the seal to open to allow the passage of the first fluid or further first fluid into the internal portion.

The method may comprise determining a state of the connector. For example, the method may comprise sensing a presence of the first fluid in the internal portion. The method may comprise sensing the fluid in the internal portion with a sensor, the sensor forming part of the apparatus, optionally the connector, during and/or after deployment of the connector. The method may comprise sensing a presence and/or state of the first fluid in the apparatus, such as in the fluid chamber of the apparatus. The method may comprise determining the state of a plurality of connectors. The method may comprise determining the state of the plurality of sensors with a single sensor. For example, the apparatus may comprise a sensor in or connected to the fluid chamber to detect a state of fluid in the fluid chamber, such as a pressure and/or type of fluid in the fluid chamber, the fluid in the fluid chamber being the first fluid for filling one or more connectors of the apparatus. In at least some examples, the method may comprise determining that the first fluid is present in the fluid chamber, such as at the deployed location. The method may comprise determining a presence (or non-presence) of the second fluid during and/or at deployment and/or subsequently.

The method may comprise multiple fillings and/or pressurisations of the first fluid in the internal portion of the connector. The method may comprise repeatedly pressurising and/or filling the internal portion of the connector with the first fluid. The method may comprise repeatedly pressurising the internal portion of the connector with the first fluid during a single deployment and/or descent of the connector. The method may comprise cyclically opening the seal to pressurise the internal portion with the first fluid whenever the external fluid pressure, such as of the first fluid in the fluid chamber, increases to generate a pressure differential across the seal that exceeds the pressure threshold. For example, as the apparatus descends to depth, the ambient pressure and corresponding pressure in the fluid chamber may increase such that the pressure differential across the seal between the first fluid in the fluid chamber and the first fluid in the internal portion of the connector increases to beyond the threshold multiple times. Each time the pressure in the fluid chamber increases to beyond the threshold, the seal opens to allow fluid communication between the fluid chamber and the internal portion. Accordingly, the first fluid in the internal portion may be pressurised multiple times. For example, if the connector seal is rated to and opens whenever a pressure differential threshold of 5 bar is reached, then the seal may open around every 50 metres as the apparatus descends.

The method may comprise balancing the pressure within the fluid chamber of the apparatus to match the ambient pressure outside the apparatus. The method may comprise balancing the pressure within the fluid chamber during deployment, such as during descent to depth of the apparatus, and/or during use of the apparatus, such as when deployed at the deployment location. The method may comprise balancing the pressure within the apparatus with a pressure compensator. The method may comprise pressurising the fluid within the fluid chamber one or more connector membrane/s, bladder/s, resilient member/s or the like.

Similarly, if the apparatus rises, such as for deployment or use at a lesser depth than previously, the pressure differential across the seal between the fluid chamber and the internal portion may be such that the seal opens to release the first fluid or pressure thereof to the fluid chamber. Accordingly, the pressure across the seal may be maintained when the apparatus is raised and/or lowered in the second fluid, such as a body of water.

The method may comprise maintaining the functionality of the apparatus in the event of a change of fluid in the fluid chamber. For example, in the event that the pressure compensator or an apparatus seal fails and allows the second fluid, such as water, to pass into the fluid chamber, the method may comprise preventing passage of the second fluid into the connector. The method may comprise having the first fluid in the internal portion of the connector pressurised to a similar pressure to the ambient pressure of the second fluid. Accordingly, the method may comprise maintaining the connector seal closed in the event of the connector being exposed to the second fluid at ambient pressure. The method may comprise maintaining a presence of an insulating liquid first fluid in the internal portion of the connector in the event of passage or a leak of the second fluid into the apparatus.

The method may comprise complying with an industry requirement or regulation, such as with API 17F, with an apparatus comprising the connector, where the apparatus is deployed at a depth greater than that for which the connector is apparently or purportedly suited or rated.

According to a further aspect there is provided an apparatus designed and/or manufactured according to the method of any other aspect, example, embodiment or claim.

According to a further aspect there are provided at least some examples of an oil/gas apparatus comprising the apparatus of any other aspect, example, embodiment or claim. The oil/gas apparatus may comprise wellhead apparatus, such as a manifold.

According to a further aspect there is provided a method of simulating or modelling the method and/or apparatus, such as a connector, according to any other aspect, embodiment, example or claim.

Another aspect of the present disclosure provides a computer program comprising instructions arranged, when executed, to implement a method in accordance with any other aspect, example, claim or embodiment. A further aspect provides machine-readable storage storing such a program. The storage may be non-transitory.

According to an aspect of the invention, there is provided computer software which, when executed by a processing means, is arranged to perform a method according to any other aspect, example, claim or embodiment. The computer software may be stored on a computer readable medium. The computer software may be tangibly stored on a computer readable medium. The computer readable medium may be non-transitory.

The invention includes one or more corresponding aspects, embodiments or features in isolation or in various combinations whether or not specifically stated (including claimed) in that combination or in isolation. For example, it will readily be appreciated that features recited as optional with respect to the first aspect may be additionally applicable with respect to the other aspects without the need to explicitly and unnecessarily list those various combinations and permutations here (e.g. the apparatus of one aspect may comprise features of any other aspect). Optional features as recited in respect of a method may be additionally applicable to an apparatus or device; and vice versa. The apparatus or device of one aspect, example, embodiment or claim may be configured to perform a feature of a method of any aspect, example, embodiment or claim. In addition, corresponding means for performing one or more of the discussed functions are also within the present disclosure.

It will be appreciated that one or more embodiments/aspects may be useful in at least providing a subsea connection.

The above summary is intended to be merely exemplary and non-limiting.

Various respective aspects and features of the present disclosure are defined in the appended claims.

It may be an aim of certain embodiments of the present disclosure to solve, mitigate or obviate, at least partly, at least one of the problems and/or disadvantages associated with the prior art. Certain embodiments or examples may aim to provide at least one of the advantages described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a schematic diagram of an assembled subsea control module (SCM) containing interconnected electrical components; Figure 2 shows the Fig. 1 subsea control module after it has descended through the water column during installation; Figure 3 shows the installed subsea control module in a failure mode with the electrical connector submerged in water; and Figure 4 is a flowchart showing a method of pressure compensating an electrical connector within a subsea control module.

Fig. 1 shows a subsea electrical connector 12 for providing a subsea electrical connection. The connector 12 has an internal portion, shown here as an inner void 35. The internal portion comprises a first fluid, shown in Fig. 2 as oil. The connector 12 has a seal 13, the seal 13 seals the internal portion from an exterior of the connector 12. The seal 13 is configured to open at a pressure differential threshold across the seal 13. The pressure differential threshold is lower than that corresponding to an atmospheric internal pressure in the internal portion and an external pressure at the exterior of the connector 10 at a location of deployed use of the connector 10.

As shown in Fig. 1, there is provided a subsea control module (SCM) 10 comprising a housing 11 with a cavity 16 filled with dielectric oil, containing various electrical/electronic components interconnected with at least one connector 12. The connector 12 comprises a body 36 defining the inner void 35 in which an electrical coupling is made. The SCM 10 is configured to descend through seawater to a subsea location whilst safeguarding the integrity of the electrical connections even if seawater leaks into the SCM housing 11.

As the depth of the SCM 10 increases, the external water pressure increases. A pressure compensation system commensurately increases the fluid pressure inside the SCM 10 such that the differential pressure exerted on the walls of the SCM housing 11 remains minimal, below a threshold value. However, as the pressure inside the SCM 10 increases, the pressure differential acting on the connector body 36 increases.

When the differential pressure acting on the connector 12 exceeds the threshold value, typically 5 bar, it temporarily opens to its surroundings, allowing oil to flow from the SCM cavity 16 to fill the connector void 35. When the SCM reaches installation depth, the fluid in the void 35 of the connector 12 is at substantially the same pressure as the fluid in both the SCM cavity 16 and the water outside the SCM 20, and the connector 12 returns to being hermetically sealed.

If a fault condition after installation allows water to enter the SCM housing 11, the oil within the connector 12 protects the electrical contacts, to help the electrical components remain fully operational even when surrounded by seawater, as required by the API Standard 17F for subsea production control systems (4th Edition, November 2017).

In Fig. 1, the SCM 10 is shown after assembly, and before installation. The SCM comprises the housing 11 (or enclosure) which defines the inner cavity 16. Under normal operating circumstances, the inner cavity 16 is hermetically sealed such that water ingress is prevented, and it is filled with dielectric oil.

Inside the SCM housing 11 is a subsea electronics module (SEM) 18 which houses multiple electronic components. The SEM is typically interconnected with one or more electrically powered valves and instruments that are also present in the SCM. In this example, the SEM is electrically coupled to a solenoid valve 19 with a plurality of wires 17 joined by the connector 12. The surrounding dielectric oil normally electrically insulates the electrical components from each other to reduce the risk of malfunction and/or short-circuiting.

The connector 12 can be an IP68 type connector, which is designed for temporary immersion in water and is sealed against water ingress up to a relatively shallow depth, of 5 bar in this example. It comprises a body portion 36 defining an inner void 35, which is sealed at either end by seals 31, 33, through each of which an electrical wire 17 passes; and across a mechanical joint of two halves of the connector body portion 36 by the body seal 13. The shape of the connector 12 inside will provide separate pockets for the crimps to sit within. This provides two purposes, firstly it provides alignment so pin/socket spacings will match up between male and female connector. Second, the walls of the pockets will ensure no electrical contact between the pins/sockets. In the void 35, the electrical contacts meet and are insulated from the body portion 36, such as by an air gap; and/or optionally a solid insulator, typically a plastic sheath/es. Thus, the electrical circuit is bridged within the connector 12.

The SCM further comprises a flexible bladder 14. The bladder 14 is for compensating the oil-filled housing 11 pressure to the external 20 pressure, due to the tendency of fluid to travel from an area of higher pressure to an area of lower pressure. The bladder 14 intakes seawater from the outside 20 of the SCM housing 11 when the external pressure 20 exceeds the SCM cavity 16 pressure, and ejects seawater if the SCM cavity 16 pressure exceeds the external pressure 20. In alternative embodiments (not shown), the bladder may be internally filled with oil such that the seawater pressure acts on the outside and compresses, rather than expands the bladder to provide pressure compensation. The bladder 14 allows for pressure compensation of the SCM cavity 16 such that the internal pressure of the SCM 10 balances the ambient external pressure of the seawater at a given depth, depending on the SCM's 10 current altitude in the water column.

During assembly of the SCM 10 and the internal components, the connector 12 is mated in dry conditions. The connector void 35 contains air at this stage. The SCM 10 is filled with the dielectric oil. The pressures inside the connector 12, inside the SCM cavity 16, and outside 20 the SCM are all equal to atmospheric pressure. The connector 12 is waterproof up to a pressure rating of 5 bar, and so it is initially sealed against the oil.

With connection and assembly complete, the SCM 10 is sealed with the oil in the cavity 16.

Subsequently, the SCM 10 is lowered into the water during the process of installation or deployment. As it descends through the water, the pressure outside 20 of the SCM 10 increases, whilst the pressure inside the SCM 10 initially stays the same. The bladder 14 intakes water and expands to compensate the internal SCM 10 pressure, as seen in Fig. 2. The volume of water inside the bladder 14 is proportional to the depth of the SCM 10. The inside of the SCM 10 is maintained at hydrostatic pressure by the bladder 14 to as the SCM 10 moves to greater depths. Accordingly, the pressure of the oil inside the SCM 10 enclosure increases as the SCM 10 descends through the water column. This is shown as step 160 of a method 100 for pressure compensating an electrical connector within an SCM, in the Fig. 4 flowchart.

The connector seals 31, 33 will remain seated until the differential pressure acting thereon reaches the waterproof limits of the connector 12, at 5 bar, which occurs at around 50 meters' depth. At this point, both of the connector seals 31, 33 become unseated and allow oil to flow from the SCM cavity 16 into the connector 12, entirely filling the connector void 35 (steps 170, 180). This state is shown in Fig. 2. The fluid in the void 35 of the connector 12 is then at substantially the same pressure as the fluid in both the SCM cavity 16 and outside the SCM 20, and the seals 31, 33 are re-seated (step 190) such that the connector 12 returns to being hermetically sealed. This sequence of steps is shown in the flowchart in Fig. 4.

A similar sequence of steps occurs when the SCM 10 reaches a lower depth where the differential between the pressure inside the connector void 35 and the pressure surrounding the connector 12 (in the SCM cavity 16) again exceeds the waterproof limits of the connector 12. Oil of the relatively higher fluid pressure will enter the connector void 35. The sequence in Fig. 4 typically repeats several times before the SCM 10 reaches its installation depth, at 3000 m. The pressure inside the connector will be approximately 300 bar, which is equal to the hydrostatic pressure at this depth.

After installation, a fault condition may occur, as shown in Fig. 3, resulting in seawater entering the SEM housing 11. Here, the bladder 14 is shown to have burst, leaking water into the SCM cavity 16. The seawater 16b mixes with the oil 16a and may immerse the connector 12. However, in such a situation, the pressures inside and outside of the connector 12 remain balanced, at approximately 300 bar, in this example, preventing any water influx into the connector 12 which would usually occur due to the hydrostatic pressure at such a depth. Therefore, the seals 31, 33 of the connector 12 remain seated, and oil remains trapped inside the connector void 35 protecting the electrical contacts within from harmful exposure to seawater. An example of an advantage of an embodiment of the present invention is that in such a situation, operation of the electrical components within the SCM 10 can continue in conformance with API 17F, and similarly as to normal atmospheric conditions.

The applicant hereby discloses in isolation each individual feature described herein and any combination of two or more such features, to the extent that such features or combinations are capable of being carried out based on the present specification as a whole in the light of the common general knowledge of a person skilled in the art, irrespective of whether such features or combinations of features solve any problems disclosed herein, and without limitation to the scope of the claims.

The applicant indicates that aspects of the present invention may consist of any such individual feature or combination of features. It should be understood that the embodiments described herein are merely exemplary and that various modifications may be made thereto without departing from the scope or spirit of the invention. For example, it will be appreciated that although shown here as comprising a single connector, in other examples multiple connectors are provided within a single SCM.

Claims

Claims 1. A subsea electrical connector for providing a subsea electrical connection, the connector comprising: an internal portion, the internal portion comprising a first fluid, a seal, the seal sealing the internal portion from an exterior of the connector, wherein the seal is configured to open at a pressure differential threshold across the seal, the pressure differential threshold being lower than that corresponding to an atmospheric internal pressure in the internal portion and an external pressure at the exterior of the connector at a location of deployed use of the connector.
2. The subsea electrical connector of claim 1, wherein the connector is rated to a waterproofness rating corresponding to IPx8 or poorer; and the location of deployed use of the connector corresponds to a pressure greater than the waterproofness rating.
3. The subsea electrical connector of claim 2, deployed, in use, at a depth greater than that corresponding to the waterproofness rating.
4. The subsea electrical connector of any preceding claim, wherein the first fluid in the internal portion is pressurised to the external pressure.
5. The subsea electrical connector of claim 4, wherein the first fluid is pressurised to the external pressure by a descent of the connector towards a depth of the location of deployed use.
6. The subsea electrical connector of any preceding clam, wherein the first fluid comprises an insulating liquid.
7. An apparatus comprising the connector of any preceding claim.
8. The apparatus of claim 6, wherein the apparatus comprises a Subsea Control Module ("SCM").
9. The apparatus of claim 6 or 7, wherein the apparatus is configured for use at the location of deployed use where the external pressure at the exterior of the connector exceeds a waterproofness rating of the connector.
10. The apparatus of any of claims 6 to 8, wherein the apparatus comprises a fluid chamber for housing the connector, the fluid chamber comprising the first fluid.
11. The apparatus of claim 10, wherein the apparatus comprises a pressurisation member for pressurising the first fluid in the fluid chamber to have a pressure to corresponding to an ambient pressure outside the apparatus.
12. The apparatus of any of claims 6 to 11, wherein the apparatus is configured for use submerged in a second fluid, the second fluid being different from the first fluid and the second fluid comprising water.
13. The apparatus of claim 11, wherein the apparatus is configured to prevent passage of the second fluid into the internal portion at least partially by the first fluid being pressurised to a pressure corresponding to the second fluid.
14. A method of subsea electrical connection, the method comprising: providing a connector with an internal portion, the internal portion comprising a first fluid; sealing the internal portion from an exterior of the connector with a seal; opening the seal at a pressure differential threshold across the seal; wherein the pressure differential threshold is lower than that corresponding to an atmospheric internal pressure in the internal portion and an external pressure at the exterior of the connector at a location of deployed use of the connector; and deploying the connector at the location of deployed use.
15. The method of claim 14, wherein the method comprises filling the internal portion of the connector with the first fluid by deploying the connector to the location of deployed use.
16. The method of claim 14 or 15, wherein the method comprises opening the seal by pressurising the first fluid external to the internal portion in order to generate the pressure differential across the seal, to allow the internal portion to receive the first fluid via the seal under pressure from the exterior of the connector.
17. The method of any of claims 14 to 16, wherein the method comprises opening the seal at a pressure lower than a pressure at the location of deployed use of the connector.
18. The method of any of claims 14 to 17, wherein the method comprises deploying the connector at a depth greater than that corresponding to a waterproofness rating of the connector.
19. The method of any of claims 14 to 18, wherein the method comprises deploying the connector in an apparatus, the apparatus comprising a Subsea Control Module ("SCM").
20. The method of claim 19, wherein the method comprises: positioning the connector within a fluid chamber of the apparatus: filling the fluid chamber with the first fluid filling the internal portion of the connector with the first fluid by pressurising the first fluid in the fluid chamber in which the connector is positioned; wherein pressurising the first fluid in the fluid chamber external to the connector is performed by lowering the apparatus a body of water to generate the pressure differential across the seal to cause the seal to open to allow the passage of the first fluid or further first fluid into the internal portion.
21. The method of claim 20, wherein the method comprises balancing the pressure within the fluid chamber of the apparatus to match the ambient pressure outside the apparatus using a pressure compensator of the apparatus.
22. The method of claim 20 or 21, wherein the method comprises maintaining the functionality of the apparatus in the event of a change of fluid in the fluid chamber in compliance with API 17F.
23. The method of any of claims 14 to 22, wherein the method comprises deploying the connector at a depth greater than 20 metres.
24. The method of any of claims 14 to 23, wherein the method comprises making or mating the connection under atmospheric pressure at surface prior to deploying the connector to the location of deployed use.
25. The method any of claims 14 to 24, wherein the sealing of the internal portion is performed prior to submersion of the apparatus in the second fluid.