GB2532759A

GB2532759A - Subsea power and communication distribution

Info

Publication number: GB2532759A
Application number: GB1421041.3A
Authority: GB
Inventors: Puchianu Silviu; David Coventry Keith
Original assignee: GE Oil and Gas UK Ltd
Current assignee: Baker Hughes Energy Technology UK Ltd
Priority date: 2014-11-27
Filing date: 2014-11-27
Publication date: 2016-06-01
Also published as: GB201421041D0

Abstract

An umbilical cable 4 containing an optical communication line 3 and a power feeding line 5 is connected to a subsea hub 1, aka a power and communication distribution module (PCDM). A wavelength division multiplexed (WDM) signal is transmitted over the optical communication line. A WDM demultiplexer 2 in the PCDM splits a received WDM signal into its component wavelengths. Each of the signals output by the demultiplexer is transmitted over a respective optical communication line 101-10n to a respective section 81-8n of a subsea production control system (SPCS) 9. Alternatively, each of the signals output by the demultiplexer is converted (111-11n, Fig. 2) to an electrical signal and the electrical signals (131-13n, Fig. 2) are transmitted to separate sections of the SPCS. The PCDM also distributes power 7 from the power feeding line to each of the sections of the SPCS. The PCDM may include a power boost module 6 for stepping up the voltage of the power feed.

Description

Subsea power and communication distribution This invention relates to a power and communication distribution module for use 5 subsea and a method of distributing power and communication to a subsea production control system.

Background

In the oil and gas industry it is often necessary to communicate from a surface (topside) located control centre with a subsea production control system (SPCS) located at a subsea well on a seabed. Communication may take the form of commands to components of the SPCS, e.g. to open or close valves depending on production requirements. It may also be necessary to receive communication data from the SPCS, e.g. from sensors located on the well which measure temperature and / or production flow rate.

In addition to communication between the surface and the SPCS, it is often necessary to provide electrical power from the surface to the SPCS to power production control elements and sensors.

The provision of both power and communication is often fulfilled using a long offset umbilical cable which contains one or more optical fibre to carry optical communications between the surface and the seabed, and metal (e.g. copper) conductor to carry electrical power between the surface and the seabed.

To appropriately direct power and communications to the proper sections of the SPCS, a power and communications distribution module is normally located at the distal end of the umbilical cable. Such modules are well-known in the art.

The present invention is directed towards overcoming some of the drawbacks associated with prior art subsea power and communication distribution modules.

Summary of the Invention

In accordance with a first aspect of the present invention there is provided a power and communication distribution module for use subsea, comprising: an optical link for receiving from an umbilical cable an optical communication comprising signal carriers of different wavelengths and means for receiving electrical power from such an umbilical cable; a wave division multiplexer for receiving said signal carriers via said optical link and providing optical outputs each comprising a respective one of said carriers for communication with a respective one of a plurality of sections of a subsea production control system; and means for distributing electrical power from said umbilical cable to such sections of a subsea production control system.

In accordance with a second aspect of the present invention there is provided a method of distributing power and communication to a subsea production control system, the method comprising the steps of: receiving an optical communication from an umbilical cable, said optical communication comprising signal carriers of different wavelengths; receiving electrical power from said umbilical cable; applying said optical communication via an optical link to a wave division zo multiplexer to provide optical outputs each comprising a respective one of said carriers; using said optical outputs to communicate with respective ones of a plurality of sections of the subsea production control system; and distributing electrical power from said umbilical cable to such sections of a subsea production control system.

The power and communication distribution module could further comprise means for transmitting the optical outputs to respective ones of the sections of a subsea production control system.

Alternatively, the power and communication distribution module could further comprise electrical to optical data convertors (E0DCs) for converting respective ones of the optical outputs to electrical outputs for communication with respective ones of the plurality of sections of a subsea production control system.

The power and communication distribution module could further comprise a power boost module operable to increase the voltage of electrical power received from the umbilical cable.

Communication between the optical link and subsea production control system could be bi-directional.

Detailed description

The invention will now be described by way of example with reference to the accompanying drawings, in which: Fig. 1 schematically shows a block diagram illustrating a power and control distribution module according to a first embodiment of the invention; and Fig. 2 schematically shows a block diagram illustrating a power and control distribution module according to a second embodiment of the invention.

Fig. 1 Fig. 1 schematically shows a block diagram illustrating a power and control distribution module (PCDM) 1 according to a first embodiment of the invention. The PCDM 1 comprises a wavelength distribution module 2 connected to an optical link 3.

The optical link 3 is configured to receive communication data from, and provide communication data to, an umbilical cable 4. The umbilical cable 4 runs between a surface location (e.g. a topside control centre) and a location on a seabed. The umbilical cable 4 contains an optical fibre for connection with optical link 3 and an electrical conductor for supplying electrical power to an electrical conductor 5 of the PCDM 1.

The optical fibre carries an optical communication signal comprising signal carriers of different wavelengths Al, A2... An. The optical communication signal is received from the umbilical cable 4 via the optical link 3 and applied to the wavelength distribution module 2. The wavelength distribution module 2 is a passive system that does not need powering.

In the wavelength distribution module, the optical communication signal is converted into optical outputs each comprising a respective one of said signal carriers. A signal corresponding to a first wavelength Ai is output on a first optical communication link 101, a signal corresponding to a second wavelength Ai is output on a second optical communication link 102, and so on until a signal corresponding to the final wavelength An is output on an nth optical link 10n.

A subsea production control system (SPCS) 9 for monitoring and controlling the production of a subsea well is located on the seabed. The SPCS 9 comprises a plurality of sections 81, 82...8n. The optical links 101 to 10n are connected to respective ones of sections 81 to 8n of the SPCS 9.

A power boost module 6 of the PCDM 1 receives electrical power from the electrical conductor of the umbilical cable 4 via a conductor 5 and provides electrical power to each of the sections 81 to 8n of the SPCS 9. The power boost module comprises a transformer which is operable to increase the voltage of power received from the electrical conductor 5. If the electrical power received from the surface is AC power, the long offset of the umbilical cable 4 can cause the voltage to drop considerably and so a voltage increase will be required by the power boost module 6 to compensate for this. If the electrical power received from the surface is direct current the voltage drop will be smaller and usually no power boost will be necessary.

Fig. 2 schematically shows a block diagram illustrating a PCDM 1 according to a second embodiment of the invention. Like numerals from Fig. 1 have been retained where appropriate.

The embodiment of Fig. 2 differs from the embodiment of Fig. 1 in that the PCDM 1 further comprises a plurality of electrical to optical converters (EODCs) 111, 112...11n. A power supply 12 receives power from the power boost module 6 and supplies power to each of EODCs 111 to 11n.

The EODCs 111 to 11 n are configured to convert optical communication signals from the wavelength distribution module 2 into electrical communication signals. These electrical communications signals are transmitted to respective ones of sections 81 to 8n of the SPCS 9 over electrical links (e.g. copper links) 131, 132...13n.

The EODCs 111 to 11n are also configured to convert electrical communication signals from the SPCS 9 into optical communication signals of different respective wavelengths for transmission to the wavelength distribution module 2, and from the wavelength distribution module 2 to the optical link 3 and up the umbilical cable 4 to a surface location.

Advantages of the invention There are numerous advantages associated with the present invention. For example, it provides a simple and reliable configuration. There is no requirement for expensive, complex and potentially unreliable optical amplifiers, such as erbium-doped optical amplifiers or RAMAN amplifiers. Such optical amplifiers may also require qualification and ruggedisation for use in a subsea environment, and so it is desirable to provide a configuration which does not include them.

The present invention does not require a router, or an Ethernet router module, as it uses straightforward point-to-point independent optical links. Prior art PCDMs would need to use routing hardware / software to achieve the same functionality.

The embodiment shown in Fig. 1 is particularly advantageous as it uses only passive elements which are highly reliable.

The invention is not limited to the specific embodiments disclosed above, and other possibilities within the scope of the invention will be apparent to those skilled in the art.

Claims

Claims 1. A power and communication distribution module for use subsea, comprising: an optical link for receiving from an umbilical cable an optical communication comprising signal carriers of different wavelengths and means for receiving electrical power from such an umbilical cable; a wave division multiplexer for receiving said signal carriers via said optical link and providing optical outputs each comprising a respective one of said carriers for communication with a respective one of a plurality of sections of a subsea production control system; and means for distributing electrical power from said umbilical cable to such sections of a subsea production control system.
2. A power and communication distribution module according to claim 1, further comprising means for transmitting the optical outputs to respective ones of the sections of a subsea production control system.
3. A power and communication distribution module according to claim 1, further comprising electrical to optical data convertors (E0DCs) for converting respective ones of the optical outputs to electrical outputs for communication with respective ones of the plurality of sections of a subsea production control system.
4. A power and communication distribution module according to any preceding claim, further comprising a power boost module operable to increase the voltage of electrical power received from the umbilical cable.
5. A power and communication distribution module according to any preceding claim which is operable so that communication between the optical link and a subsea production control system is bi-directional.
6. A power and communication distribution module according to any preceding claim in conjunction with an umbilical cable and a subsea production control system.
7. A method of distributing power and communication to a subsea production control system, the method comprising the steps of: receiving an optical communication from an umbilical cable, said optical communication comprising signal carriers of different wavelengths; receiving electrical power from said umbilical cable; applying said optical communication via an optical link to a wave division multiplexer to provide optical outputs each comprising a respective one of said carriers; using said optical outputs to communicate with respective ones of a plurality of sections of the subsea production control system; and distributing electrical power from said umbilical cable to such sections of the subsea production control system.
8. A method according to claim 7, further comprising the step of providing electrical to optical data converters (E0DCs) to convert respective ones of the optical outputs to electrical outputs to communicate with respective ones of the plurality of sections of the subsea production control system.
9. A method according to claim 7 or 8, further comprising using a power boost module to increase the voltage of electrical power received from the umbilical cable.
10. A method according to any of claims 7 to 9, wherein communication between the optical link and subsea production control system is bi-directional.
11. A power and communication distribution module substantially as hereinbefore described with reference Figs. 1 and 2.
12. A method of distributing power and communication to a subsea production control system substantially as hereinbefore described with reference to the accompanying figures.