Morecambe gas fields
{{Short description|Gas field}}
{{Infobox oil field
|name=Morecambe South gas field
|coordinates={{Coord|53|50|48|N|3|34|51|W|display=inline,title|region:GB_type:waterbody}}
|country=United Kingdom
|region=Irish Sea
|locblocks=UK Block 110/2a and extends into Blocks 110/3a, 110/8a, 110/7a
|offonshore=offshore
|operators=Hydrocarbons GB Limited, British Gas E & P Ltd, Centrica plc, Spirit Energy|owner=Hydrocarbons GB Limited, British Gas E & P Ltd, Centrica plc, Spirit Energy
|discovery=September 1974
|startofproduction=January 1985
|producingformations=Triassic sandstone
|contractors=see text
|est_gas_bcm=150
| location_map = North West England#England
| location_map_text = Location in North West England##Location in England
| relief = y
}}
The Morecambe gas fields are two major natural gas producing fields in the Irish Sea, 27 km west of Blackpool and Morecambe Bay.
The fields
The Morecambe South field is in UK Block 110/2a and extends into Blocks 110/3a, 110/8a, 110/7a; Morecambe North is in Block 110/2a. The fields were discovered in September 1974 and February 1976 respectively.{{Cite book|last=Department of Trade and Industry|title=The Energy Report|publisher=HMSO|year=1994|isbn=0115153802|location=London|pages=73, 74, Map 3}} {{Cite book|last=More|first=Charles|title=Black Gold|publisher=continuum|year=2009|isbn=9781847250438|location=London|pages=165–6}} The fields are named after a light-ship station, they are sometimes erroneously called Morecambe Bay.
The gas reservoir is a Triassic sandstone and has the following characteristics.{{Cite book|last=Oilfield Publications Limited|title=The North Sea Platform Guide|publisher=Oilfield Publications Limited|year=1985|location=Ledbury|pages=526–39}} {{Cite web|title=The South Morecambe Gas Field, Blocks 110/2a, 110/3a, 110/7a and 110/8a, East Irish Sea|url=https://mem.lyellcollection.org/content/20/1/107|access-date=6 November 2021|website=lyellcollection.org}}
| class="wikitable"
|+Morecambe reservoir properties |Reservoir depth, feet |2,200 to 3,750 |
| Gas column, feet
|1,650 |
| Porosity, %
|12-15 |
| Nitrogen content, %
|7-8 |
| Pressure at depth
|1,875 psi @ 3,750 feet |
| Recoverable reserves, trillion cubic feet (1985)
|5. 2 |
| Recoverable reserves South billion cubic metres (1994)
|150.0 / 5.2 Tcf |
| Recoverable reserves North billion cubic metres (1994)
|35.0 / 1.2 Tcf |
Owner and operator
In 1985 the sole licensee of the field and the operator was Hydrocarbons GB Limited. This had become British Gas E & P Ltd by 1994, then Centrica plc in 1997. In 2017, Centrica launched Spirit Energy a joint venture with German energy and infrastructure company Stadtwerke München (SWM). Spirit Energy assumed ownership of the Morecambe gas fields.{{Cite web|title=Spirit Energy infrastructure|url=https://www.spirit-energy.com/media/1551/icop_morecambe-hub_final.pdfhttps://www.spirit-energy.com/media/1551/icop_morecambe-hub_final.pdf|access-date=6 November 2021|website=spirit-energy.com}}
Development
The Morecambe gas fields development was to provide peak UK demand for gas in the winter. Morecambe South was developed around a central drilling, production and accommodation complex. This comprised three bridge linked platforms plus a bridge-linked flare tower. Details of the platforms are as shown.
| class="wikitable"
|+Morecambe South central complex platforms !Platform !CPP1 !AP1 !DP1 |
| Type
|Steel jacket |Steel jacket |Steel jacket |
| Function
|Central processing |Accommodation for 176 |Wellhead drilling |
| Coordinates
|53°50’48”N 03°34’51”W |53.846667N 3.580556W |53.846861N 3.580556W |
| Water depth, metres
|26 |26 |26 |
| Design contractors
|Matthew Hall Eng. |Matthew Hall Eng. |Worley-Atkins |
| Topsides fabrication
|Wm Press, Wallsend | | |
| Topside installation
|March 1984 |June 1984 |1985 |
| Jacket fabrication
|RGC Offshore, Methil |RGC Offshore, Methil |McDermott, Ardesier |
| Jacket weight, tonnes
|11,754 |4,100 |5,500 |
| Jacket installation
|October 1983 |March 1984 |April 1984 |
| Legs
|8 |4 |4 |
| Piles
|32 |12 | |
| Wells
|– |– |16 (5-8 planned) |
| Startup
|January 1984 |– |1985 |
| Export to
|Barrow, 39 km 36-inch pipeline |– |CPP1 via bridge |
The central complex Flare tower (53.846667N 3.580556W) is linked by a bridge to the CPP1 platform. It is supported by a 3-leg jacket.
In addition to the central DP1 drilling and wellhead platform, four other wellhead platforms were installed in the field, each producing well fluids to the CPP1 platform.
| class="wikitable"
|+Morecambe South wellhead platforms !Platform !DP3 !DP4 !DP6 !DP8 |
| Type
|Steel jacket |Steel jacket |Steel jacket |Steel jacket |
| Function
|Wellhead drilling |Wellhead drilling |Wellhead drilling |Wellhead drilling |
| Coordinates
|53°49’00”N 03°33’37”W |53°52’34”N 03°39’39”W |53.867278N 3.616650W |53.891872N 3.622833W |
| Water depth, metres
|30 |30 |32 |32 |
| Accommodation
|6 |6 | | |
| Design contractors
|Worley-Atkins |Worley-Atkins | | |
| Topsides weight, tonnes
|5,200 |5,200 | | |
| Topside installation
|September 1983 |July 1984 | | |
| Jacket fabrication
|McDermott, Ardesier |Howard Doris, Kishorm | | |
| Jacket weight, tonnes
|5,500 |5,500 | | |
| Jacket installation
|July 1983 |July 1984 | | |
| Legs
|4 |4 | | |
| Wells
|16 (5-8 planned) |16 (5-8 planned) | | |
| Startup
|1985 |1985 |1985 |1985 |
| Export to
|CPP1, 3.5 km 24-inch pipeline |CPP1, 3.5 km 24-inch pipeline |CPP1, 3.2 km 24-inch pipeline |CPP1, 5.8km 24-inch pipeline |
Because the gas reservoir is shallow, and to avoid a large deviation of the wells, slant drilling is used. Two jack up drilling rigs were built to undertake 30 degree slant drilling. The rigs were Morecambe Flame and Bay Driller.
File:Morecambe North gas platform (DPPA).jpg
In 1984 a single drilling and production platform was installed in the Morecambe North field. {{Cite web|title=South Morecambe DP3-DP4 Decommissioning Environmental Appraisal|url=https://www.spirit-energy.com/media/1060/dp34-environmental-appraisal-1.pdf|access-date=6 November 2021|website=spirit-energy.com}}
| class="wikitable"
!Platform !Block !Coordinates !Water depth !Operational !Export |
| Morecambe North
|110/2a |53.960578N 3.670694W |29 metres |October 1994 |37 km pipeline to Barrow |
The Bains field was developed in 2002 by a single subsea wellhead producing well fluids to DP1 via a 8.3 km 8-inch pipeline.
The Bains field was developed in 2002 by a single subsea wellhead producing well fluids to DP1 via a 8.3 km 8-inch pipeline.
| class="wikitable"
!Field !Block !Coordinates !Water depth !Operational |
| Bains
|110/3c |53.875833N 3.465556W |18 metres |2002 |
The North Morecambe platform was modified to tie in the Millom East / West and Dalton fields, and in 2013 the addition of the Rhyl field.
Production
Well fluids from the wellhead platforms are piped to the CPP1 platform. Three phase separation into gas, condensate and water is undertaken. The gas is dehydrated using tri-ethylene glycol. Dry gas together with condensate is piped ashore.
Initial production from Morecambe South field in the winter of 1984-5 was 120 million standard cubic feet of gas per day (MMSCFD). This increased to 450 MMSCFD in the winter of 1985-6 and ultimately to 1,200 MMSCFD. The first year of peak production was 1993 when the South field produced 8.6 billion cubic metres per year.
The first year of peak production for the Morecambe North field was 1995 when the field produced 3.1 billion cubic metres of gas per year.
Decommissioning
The decommissioning of the DP3 and DP4 platforms is currently (2021) underway. {{Cite web|title=South Morecambe DP3-DP4 Decommissioning Programmes|url=https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/779729/Morecambe_DP3_DP4_Decommissioning_Programme.pdf|access-date=6 November 2021|website=gov.uk}}