GB2477714A

GB2477714A - Retrievable instrumentation module for connection to a subsea installation

Info

Publication number: GB2477714A
Application number: GB1000650A
Authority: GB
Inventors: Martin Fleet; Rauldon Edwards
Original assignee: SUBSEA CONTROLS Ltd
Current assignee: SUBSEA CONTROLS Ltd
Priority date: 2010-01-15
Filing date: 2010-01-15
Publication date: 2011-08-17
Also published as: GB201000650D0

Abstract

Retrievable instrumentation module for connection to a subsea installation Apparatus and method for recovery of a subsea instrumentation module 23 coupled to a sensor module 21 on a subsea installation. The sensing module 21 and retrievable module 23 are connected through a releasable wet-mate connector 25. The retrievable module is configured to provide power to, and receive data from, the sensor module 21. The electronic components are housed in an electronics module 13 (fig 5 and 6) within a pressure isolated or pressure compensating chamber. The electronics module 13 connects to a remote data acquisition system by an electrical or optical cable or an audio or electromagnetic link. The electronics module 13 may be integrated into an electrical cable (fig 3) which connects the retrievable module to a remote data acquisition system. The subsea instrumentation module is retrievable by a ROV or diver.

Description

1 Subsea Instrumentation Assembly 3 The present invention relates to a subsea instrumentation assembly and methods of use, 4 and in particular a subsea instrumentation assembly suitable for use with a fluid conduit.

6 BackQround to the invention 8 This invention relates to subsea instrumentation assemblies for subsea installations.

9 Despite the name, such instrumentation assemblies are employed in underwater installations both subsea and in freshwater environments.

12 The control of underwater fluid extraction wells, for example subsea hydrocarbon 13 production wells, is managed by a subsea electronics module (SEM), also referred to as 14 data acquisition module, which is typically housed in a subsea control module (SCM). This in turn is conventionally mounted on a structure located on the seabed such as a subsea 16 xmas tree, subsea manifold, subsea pumping station or subsea hydrocarbon processing 17 system. Existing SEMs supply power, and communicate via electrical cables to a variety of 18 subsea instrumentation located on the subsea structure that intrude into the fluid conduit 19 for the purpose of measuring properties such as but not limited to pressure, temperature, and/or chemical properties.

2 Figure 1 is a sectional view of an example of a conventional subsea instrument 10 secured 3 to a subsea pipe 17 with a conduit 18. The instrument 10 comprises a flange 14 secured to 4 the pipe 17 and the instrument body 12 housing a sensor electronics module 13. The flange portion 14 normally conforms to the American Petroleum Institute (API) 6 specifications. A nose 15 comprising a sensor(s) 16 is secured to the instrument 10 and 7 intrudes into the fluid conduit 18 of the pipe 17. The sensor(s) 16 collect data which may 8 relate to pressure, temperature, and/or chemical properties of a fluid in the conduit 18.

9 The sensor electronics module 13 receives a signal from the sensor(s) 16, converts this signal and provides onward communication between the sensor electronics module 13 and 11 the data storage or processing equipment (such as a subsea electronics module) located 12 subsea, or on the surface via a cable 11. Connection between the cable 11 and the 13 instrument 10 is by means of an integral connector which is made up in the factory, or by a 14 connector that can be mated subsea.

16 Once installed, subsea instruments are difficult to retrieve, particularly those that intrude 17 into a fluid conduit, as this may require isolation of the fluid conduit and onerous 18 connection! disconnection methods. The instrument 10, the flange 14, and the pipe 17, 19 between them form a pressure barrier between the inside of the pipe 18 and the external environment. It will be appreciated that removal of the instrument 10, can be highly 21 complicated due to the need to retain the integrity of the containment of the pipe 17.

22 Removal of the instrument 10 (if indeed it is possible) is a risk to the environment, and may 23 also be very expensive.

It is an object of an aspect of the present invention to obviate or at least mitigate the 26 disadvantages of conventional subsea instrumentation systems. Further aims and objects 27 of the invention will become apparent from the following description.

1 Summary of the invention

3 According to a first aspect of the invention there is provided a subsea instrumentation 4 assembly comprising: a sensor module configured for attachment to a subsea installation, the sensor module 6 comprising at least one sensor; 7 a retrievable instrumentation module comprising electronic components functionally 8 associated with the operation of the sensor module; 9 a wet-mate connector for releasable coupling of the retrievable instrumentation module to the sensor module.

12 The provision of a wet-mate connector allows the instrumentation module to be releasably 13 coupled to the at least one sensor, so that the electronic components therein may be 14 retrieved from subsea to surface without retrieving the entire assembly. In this way the sensor module and the at least one sensor (which may be intrusive to or otherwise 16 secured to a fluid conduit) can be left in-situ on a subsea installation. The invention 17 provides an interface between electrical components associated with operation of a sensor 18 and the sensor itself which allows the instrumentation module to be retrieved to surface for 19 servicing and/or replacement in the event of failure of the electronics or the wet-mate connector. The invention therefore makes certain elements which may be prone to failure 21 (i.e. the electronic components) retrievable whilst leaving high reliability components (i.e. 22 the at least one sensor) in-situ.

24 The subsea installation may for example be a subsea pipeline, manifold, subsea pumping station, subsea processing unit, or christmas tree. The sensor module may be attached to 26 the subsea installation in a manner that conforms to industry practice, for example 27 American Petroleum Institute (API) specifications. The sensor module may be secured to 28 the subsea installation by bolts, and may comprise a flange.

The electronic components of the retrievable instrumentation module may be housed in an 31 electronics module, which may comprise a pressure isolating chamber. The pressure 32 isolating chamber may be a pressure compensated or pressure containing chamber.

34 Preferably, the electronics module is configured to be coupled to a subsea electronics module (SEM), which may be located remotely from the subsea instrumentation assembly.

1 The electronics module may be connected to a subsea electronics module via one or more 2 of the following: an electrical cable; a fibre optic cable; an acoustic communication link; 3 and an electromagnetic communication link.

In one embodiment, the electronics module is integrated into an electrical cable which 6 connects the retrievable instrumentation module to a remote subsea electronics module or 7 other data acquisition module. However, in an alternative embodiment, the electronics 8 module is disposed between the electrical cable and the wet-mate connector. The 9 electronics module may be located in a body of the retrievable instrumentation module, and the electrical cable may be attached to the body.

12 The subsea instrumentation assembly may further comprise a power source, which may 13 for example be a battery. The battery may be located in the retrievable instrumentation 14 module. The battery may therefore be retrieved to surface for replacement and/or recharging if required, leaving the at least one sensor in-situ.

17 The subsea instrumentation assembly may comprise a plurality of subsea sensors. The 18 plurality of subsea sensors may be located in a single sensor housing or single sensor 19 module. The retrievable instrumentation module may be configured to provide power to and receive data from the single sensor housing or module.

22 According to a second aspect of the invention, there is provided a subsea instrumentation 23 module comprising: 24 an electronics module comprising electronics components functionally associated with the operation of at least one sensor; and 26 an interface for releasable coupling of the electronics module to a wet-mate connector 27 located on a sensor module attached to a subsea installation, such that when 28 connected the electronics module is in communication with at least one sensor located 29 iii the sensor module.

31 Embodiments of the second aspect of the invention may comprise features of the first 32 aspect of the invention and its embodiments.

34 According to a third aspect of the invention, there is provided a method of retrieving an electronics module from a subsea installation, the method comprising: 1 providing an instrumentation assembly on a subsea installation, the assembly 2 comprising a sensor module attached to the subsea installation;, a wet-mate connector; 3 and an electronics module comprising electronic components functionally associated 4 with the operation of the sensor module; releasing the wet-mate connector to separate the electronics module from the sensor 6 module; 7 retrieving the electronics module to surface, leaving the sensor module attached to the 8 subsea installation.

The method may comprise the additional steps of servicing and/or replacing the 11 electronics module. The electronics module may be retrieved from the subsea installation 12 by a remotely operated vehicle (ROV) or a diver.

14 Embodiments of the third aspect of the invention may comprise the features of the first and/or second aspects of the invention and their embodiments.

1 Brief Descrirtion of the Drawings 3 Aspects and advantages of the present invention will become apparent upon reading the 4 following detailed description and upon reference to the following drawings in which: 6 Figure 1 is a sectional view of a conventional subsea instrumentation assembly connected

7 to a pipeline (prior art);

9 Figure 2 is a sectional view of a subsea instrumentation assembly and subsea pipe in accordance with one embodiment of the present invention wherein the electronics module 11 is embedded within the body of the retrievable connecting member; 13 Figure 3 is a sectional view of a subsea instrumentation assembly and subsea pipe in 14 accordance with one embodiment of the present invention wherein the electronics module is embedded within the cable harness connected to the retrievable connecting member; 17 Figure 4 is a sectional view of a subsea instrumentation assembly and subsea pipe in 18 accordance with one embodiment of the present invention wherein the electronics module 19 has a battery pack embedded within the body of the retrievable connecting member and communicates with a data acquisition module acoustically or electromagnetically; 22 Figure 5 is a sectional view of the typical electronics components within one embodiment 23 of the present invention whereby a sensor element is connected to the electronics with 24 digital communications to a data acquisition module; 26 Figure 6 is a sectional view of the typical electronics components within an alternative 27 embodiment of the present invention whereby the sensor element is connected to the 28 electronics with analogue (4-2OmA) signalling to a data acquisition module.

1 Detailed Description of the Invention

3 Referring to Figure 2, there is shown generally at 20 a subsea instrumentation assembly 4 comprising a retrievable instrumentation module 23, a sensor module 21 and subsea pipe 17. The subsea pipe 17 comprises a bore 18 for the flow of fluids. It will be appreciated 6 that the instrumentation assembly of the invention is not limited to pipeline applications, 7 and may be used with subsea manifolds, xmas trees, high integrity pipeline protection 8 system (HIPPS), subsea hydrocarbon processing units, pumping stations, flowline 9 jumpers, spools or indeed anywhere in the process.

11 The sensor module 21 has flange portion 14 which is secured to the pipe 17 and a nose 12 portion 15 comprising a sensor 16 which intrudes into the bore 18 of the pipe 17. (It 13 should be noted in all cases, that the nose of the sensor may be set back from the bore 14 but still exposed to the fluid). The sensor 16 collects data from the bore, and in this example could be a temperature measuring device, a pressure transmitter (for example 16 strain gauge or quartz transducer), a corrosion monitoring probe, or a combination of one 17 or more sensors configured to collect data relating to pressure, temperature and/or 18 chemical properties of fluid or fluids in the bore 18.

The sensor module 21 is provided with two pressure isolation barriers 26, which separates 21 the sensor 16 from a connecting portion 24a of the sensor module. In this embodiment, 22 the connecting portion 24a includes male connectors 25a which correspond to female 23 connectors 25b in the connecting portion 24b of the instrumentation module 23. The 24 connectors 25a and 25b together form an interface through which electrical, electronic, and/or optical signals can be transmitted between the sensor module 21 and the 26 instrumentation module 23. The connector 25 is a wet-mate connector as is known in the 27 art, and is configured for reliable and repeated connection and disconnection.

29 The instrument module 23 comprises a body 12 which has at one end of the connecting portion 24b for the sensor module and at the opposing end a handle 22 for ROV 31 manipulation. The connecting portion 24b comprises female connectors 25b which 32 correspond to the male connectors 25a on the sensor module 21. The ROV handle 22 is 33 used to separate the instrument module 23 from the sensor module 21 and could 34 alternatively be a diver operated handle (for example in shallow water applications).

1 An electronics module 13 is located within the body 12 of the instrument module 23, and is 2 in communication with the sensor 16 within the sensor module 21 via the interface 24 to 3 fulfil a number of data collection, storage, pre-processing, and processing functions, as 4 well as to provide controlling and/or power signals for the sensor module.

6 The instrumentation module 23 communicates with and receives power from the subsea 7 electronics module (SEM) or other data acquisition system, or to surface via cable harness 8 11, which is typically connected to the instrument module 23 at manufacture.

Figure 3 is a sectional view of an instrumentation assembly 30 in accordance with another 11 embodiment of the present invention. Instrumentation assembly 30 is similar to and will be 12 understood from the instrumentation shown in Figure 2 but differs in that the electronics 13 module 13 (which is similar to electronics module 13 shown in Figure 2) is embedded in 14 the cable harness 11 and not the body 12 of the instrumentation module 23.

16 Figure 4 is a sectional view of an instrumentation assembly 40 in accordance with another 17 embodiment of the present invention. Instrumentation assembly 40 is similar to and will be 18 understood from the instrumentation shown in Figure 2 but differs in that the electronics 19 module 13 (which is similar to electronics module 13 shown in Figure 2) is powered by its own power pack 28 thus not requiring cable harness 11 connected back to a data 21 acquisition module.

23 Including a power pack 28 with the electronics module 13 allows the electronics module 13 24 to communicate using either electromagnetic or acoustic transmission 27 of the sensor data 16 to the subsea electronics module or other data acquisition system without the 26 need for cable harness 11. The instrument module 23 can be retrieved to the surface 27 using an ROV or by a diver, in the manner described above with reference to the system 28 of Figure 2. Recovery in such a manner allows not only replacement of failed 29 components, but also replacement or re-charge of the power pack 28.

31 An exemplary electronics module will now be described in more detail below with 32 reference to Figure 5. The Figure is a schematic representation of the internal 33 components of the electronics module 13. The electronics module 13 comprises a 34 housing 50 containing an isolated DC/DC converter 41, an analogue/digital gauge 1 interface 42, an isolated digital communications interface 43 and an embedded micro- 2 controller 44.

4 The electronics module 13 is connected to a data acquisition module (not shown) via an electrical cable 11 utilising a multi-pin connector 45 located at one end of the housing 50.

6 The sensor module is connected to the electronics module 13 via a second multi-pin 7 connector 46 located at the opposing end of the housing 50. A wet-mate connector 25a 8 and 25b connects the electronics module 13 to the sensor module 16.

Power from the data acquisition module enters the electronics module 13 via the electrical 11 cable 11 and multi-pin connector 45. Power is supplied to the isolated DC/DC converter 12 41 with the nominal supply, which typically is 24V DC. The isolated DC/DC converter 41 13 generates the required low voltage, low noise electrical power supply for the other 14 components of the electronics module 13.

16 The embedded micro-controller 44 communicates with the remote data acquisition module 17 via the isolated digital communications interface 43. The embedded micro-controller 44 is 18 operably connected to the isolated digital communications interface 43 and is the main 19 control system in the electronics module 13. The electronics module 13 interfaces with the sensor and gauge module 16 via the analogue/digital gauge interface 42 and multi-pin 21 connector 46. Readings from the sensor module 16 pass through the wet-mate connector 22 25 and multi-pin connector 46, the analogue/digital gauge interface 42, the embedded 23 micro-controller 44, the isolated digital communications interface 43 and the multi-pin 24 connector 45 to the data acquisition module (not shown).

26 In use the analogue/digital gauge interface 42 provides the required power to the sensor 27 16 and converts the analogue signals from the sensor and gauge module into digital 28 values, forwarding theses values to the embedded micro-controller 44. The embedded 29 micro-controller 44 samples the sensor module 16 on a regular basis. The rate of sampling is determined by the update rate of the system. The embedded micro-controller 31 44 configures the analogue data received from the gauge and sensor module 16 into an 32 appropriate format and replies to the data acquisition module with the process data.

34 The embedded micro-controller contains or interfaces to the necessary line driver for the particular type of communications bus employed in the isolated communications interface 1 43. The isolated communications interface 43 is able to communicate with the Data 2 Acquisition Module via the multi-pin connector 45 and cable 11. Suitable interfaces may 3 include CANBus, Profibus, TCP/IP, RS-485 or RS-232.

In yet a further alternative embodiment, shown in Figure 6, the electronics module 13' 6 does not include the embedded micro-controller 44 or the isolated communications 7 interface 43, but instead uses standard analogue modulation 49, in the form of a 4-2OmA 8 current signal, directly over one or more 4-2OmA interfaces. In use the analogue gauge 9 interface 52 provides the required power to the gauge and sensor 16 and directly modulates the 4-2OmA communications circuit 49. In this case the data acquisition 11 module would provide the necessary 4-2OmA drive and reception circuit and would be 12 connected to the electronics module 13 via the connecter 45 of the housing 50.

14 Reliability of the electronics modules 13 and 13' is affected by environmental influences such as excessive heat, vibration and humidity and the ingress of sea water due to the 16 failure of one or more seals. These environmental influences may cause premature failure 17 of the components 41, 42, 43, 44 of the electronics module 13. Preferred embodiments of 18 the invention use components selected to operate over a wide temperature range 19 providing protection against excessive heat. The electronics modules 13 and 13' also mounted to an internal structure of the vessel 50 so as to isolate the electronics modules 21 from extreme vibration. To protect the electronics modules 13, 13' from the humidity of the 22 surrounding environment the electronics modules are coated with a coating that prevents 23 moisture ingress into the components and circuit boards.

The above measures may mitigate the risk of failure of the electronics and instrumentation 26 and may decrease the failure rate of the subsea instrument assembly. However, the 27 instrumentation assembly may still be at risk of failure in extreme conditions, and even in 28 the absence of an instrument failure a regular servicing and/or repair schedule is required 29 to ensure reliable operation of the installation.

31 The foregoing description of the invention has been presented for purposes of illustration 32 and description and is not intended to be exhaustive or to limit the invention to the precise 33 form disclosed. The described embodiments were chosen and described in order to best 34 explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilise the invention in various embodiments and with various 1 modifications as are suited to the particular use contemplated. Therefore, further 2 modifications or improvements may be incorporated without departing from the scope of 3 the invention herein intended.

Most of the description hereinbefore is the use of the invention with equipment used in the 6 extraction of oil or natural gas from subsea locations. It will be appreciated however, that 7 the invention is also suitable for use in other applications. For example it may be used in 8 offshore or subsea electrical generation applications. When used in such applications, it 9 will be appreciated that the sensors concerned will be associated with different measurements than those in the applications described hereinbefore.

12 It will be appreciated that a wide range of modifications and alterations may be made to 13 the arrangements described hereinbefore without departing from the scope of the 14 invention.

Claims

1 Claims 3 1. A subsea instrumentation assembly comprising: 4 a sensor module configured for attachment to a subsea installation, the sensor module comprising at least one sensor; 6 a retrievable instrumentation module comprising electronic components 7 functionally associated with the operation of the sensor module; and 8 a wet-mate connector for releasable coupling of the retrievable instrumentation 9 module to the sensor module.

11

2. The subsea instrumentation assembly as claimed in claim 1 wherein the 12 retrievable instrumentation module is configured to provide power to and 13 receive data from the sensor module.

3. The subsea instrumentation assembly as claimed in any preceding claim 16 wherein the electronic components of the retrievable instrumentation module Q 17 are housed in an electronics module and the electronics module comprises a 18 pressure isolating chamber. N19

4. The subsea instrumentation assembly as claimed in claim 3 wherein the T 21 pressure isolating chamber is a pressure compensating chamber.23

5. The subsea instrumentation assembly as claimed in any preceding claim 24 wherein the electronics module is configured to be coupled to a subsea electronics module (SEM).27

6. The subsea instrumentation assembly as claimed in claim 4 wherein the 28 subsea electronics module (SEM) is located remotely from the subsea 29 instrumentation assembly.31

7. The subsea instrumentation assembly as claimed in claim 5 or claim 6 wherein 32 the electronics module is connected to a subsea electronics module (SEM) via 33 one or more of the following: an electrical cable; a fibre optic cable; an acoustic 34 communication link; and an electromagnetic communication link.1

8. The subsea instrumentation assembly as claimed in claim 7 wherein the 2 electronics module is integrated into an electrical cable which connects the 3 retrievable instrumentation module to a remote subsea electronics module 4 (SEM).6

9. The subsea instrumentation assembly as claimed in claim 8 wherein the 7 electronics module is disposed between the electrical cable and the wet-mate 8 connector.

10. The subsea instrumentation assembly as claimed in claim 9 wherein the 11 electronics module is located in a body of the retrievable instrumentation 12 module and the electrical cable is attached to the body.14

11. The subsea instrumentation assembly as claimed in any preceding claim further comprising a battery located in the retrievable instrumentation module.17

12. The subsea instrumentation assembly as claimed in any preceding claim 18 comprising a plurality of subsea sensors in a single sensor module.

13. A subsea instrumentation module comprising: 21 an electronics module comprising electronics components functionally 22 associated with the operation of at least one sensor; and 23 an interface for releasable coupling of the electronics module to a wet-mate 24 connector located on a sensor module attached to a subsea installation, such that when connected the electronics module is in communication with at least 26 one sensor located in the sensor module.28

14. The subsea instrumentation module as claimed in claim 13 configured to 29 provide power to and receive data from the sensor module.31

15. The subsea instrumentation module as claimed in claim 13 or 14 wherein the 32 electronics module comprises a pressure isolating chamber.34

16. The subsea instrumentation module as claimed in claim 15 wherein the pressure isolating chamber is a pressure compensating chamber.1

17. The subsea instrumentation module as claimed in any of claims 13 to 16 2 wherein the electronics module is configured to be coupled to a subsea 3 electronics module (SEM).

18. The subsea instrumentation module as claimed in claim 17 wherein the subsea 6 electronics module (SEM) is located remotely from the subsea instrumentation 7 assembly.9

19. The subsea instrumentation module as claimed in claim 18 wherein the electronics module is connected to a subsea electronics module via one or 11 more of the following: an electrical cable; a fibre optic cable; an acoustic 12 communication link; and an electromagnetic communication link.14

20. The subsea instrumentation module as claimed in claim 19 wherein the electronics module is integrated into an electrical cable which connects the 16 retrievable instrumentation module to a remote subsea electronics module 17 (SEM).19

21. The subsea instrumentation module as claimed in claim 20 wherein the electronics module is disposed between the electrical cable and the wet-mate 21 connector.23

22. The subsea instrumentation module as claimed in claim 20 further comprising a 24 body, wherein the electronics module is located in the body and the electrical cable is attached to the body.27

23. The subsea instrumentation module as claimed in any of claims 14 to 22 further 28 comprising a power source.

24. The subsea instrumentation module as claimed in claim 23 wherein the power 31 source is a battery.33

25. A method of retrieving an electronics module from a subsea installation, the 34 method comprising: providing an instrumentation assembly on a subsea installation, the assembly 36 comprising a sensor module attached to the subsea installation; a wet-mate 1 connector; and an electronics module comprising electronic components 2 functionally associated with the operation of the sensor module; 3 releasing the wet-mate connector to separate the electronics module from the 4 sensor module; retrieving the electronics module to surface, leaving the sensor module 6 attached to the subsea installation.8

26. The method as claimed in claim 25 comprising the additional step of servicing 9 or replacing the electronics module.11

27. The method as claimed in claim 25 or claim 26 wherein the electronics module 12 is retrieved from the subsea installation by a remotely operated vehicle (ROV) 13 or a diver. (\J