Morecambe gas fields explained

Morecambe South gas field
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.[1] [2] 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.[3] [4]

Reservoir depth, feet
2,200 to 3,750
Gas column, feet1,650
Porosity, %12-15
Nitrogen content, %7-8
Pressure at depth1,875 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.[5]

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.

Morecambe South central complex platforms!Platform!CPP1!AP1!DP1
TypeSteel jacketSteel jacketSteel jacket
FunctionCentral processingAccommodation for 176Wellhead drilling
Coordinates53°50’48”N 03°34’51”W53.846667N 3.580556W53.846861N 3.580556W
Water depth, metres262626
Design contractorsMatthew Hall Eng.Matthew Hall Eng.Worley-Atkins
Topsides fabricationWm Press, Wallsend
Topside installationMarch 1984June 19841985
Jacket fabricationRGC Offshore, MethilRGC Offshore, MethilMcDermott, Ardesier
Jacket weight, tonnes11,7544,1005,500
Jacket installationOctober 1983March 1984April 1984
Legs844
Piles3212
Wells16 (5-8 planned)
StartupJanuary 19841985
Export toBarrow, 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.

Morecambe South wellhead platforms!Platform!DP3!DP4!DP6!DP8
TypeSteel jacketSteel jacketSteel jacketSteel jacket
FunctionWellhead drillingWellhead drillingWellhead drillingWellhead drilling
Coordinates53°49’00”N 03°33’37”W53°52’34”N 03°39’39”W53.867278N 3.616650W53.891872N 3.622833W
Water depth, metres30303232
Accommodation66
Design contractorsWorley-AtkinsWorley-Atkins
Topsides weight, tonnes5,2005,200
Topside installationSeptember 1983July 1984
Jacket fabricationMcDermott, ArdesierHoward Doris, Kishorm
Jacket weight, tonnes5,5005,500
Jacket installationJuly 1983July 1984
Legs44
Wells16 (5-8 planned)16 (5-8 planned)
Startup1985198519851985
Export toCPP1, 3.5 km 24-inch pipelineCPP1, 3.5 km 24-inch pipelineCPP1, 3.2 km 24-inch pipelineCPP1, 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.In 1984 a single drilling and production platform was installed in the Morecambe North field. [6] 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.

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. [7]

See also

Notes and References

  1. Book: Department of Trade and Industry. The Energy Report. HMSO. 1994. 0115153802. London. 73, 74, Map 3.
  2. Book: More, Charles. Black Gold. continuum. 2009. 9781847250438. London. 165–6.
  3. Book: Oilfield Publications Limited. The North Sea Platform Guide. Oilfield Publications Limited. 1985. Ledbury. 526–39.
  4. Web site: The South Morecambe Gas Field, Blocks 110/2a, 110/3a, 110/7a and 110/8a, East Irish Sea. 6 November 2021. lyellcollection.org.
  5. Web site: Spirit Energy infrastructure. 6 November 2021. spirit-energy.com.
  6. Web site: South Morecambe DP3-DP4 Decommissioning Environmental Appraisal. 6 November 2021. spirit-energy.com.
  7. Web site: South Morecambe DP3-DP4 Decommissioning Programmes. 6 November 2021. gov.uk.