Leman gas field

The Leman gas field is a natural gas field located in the North Sea northeast of Great Yarmouth, United Kingdom. Named after the Leman Sandbank beneath which it is situated, the gas reservoir is a long, wide, thick Rotliegendes sandstone reservoir at a depth of about.
Following its discovery in August 1966, the reservoir was divided into blocks 49/26 and 49/27 to facilitate the licensing of mineral rights. Block 49/26 has been licensed to Shell since the beginning, with Block 49/27 originally licensed to the Amoco-Gas Council joint venture before being transferred to Perenco UK Ltd. Production of natural gas and condensates began in 1968, with both products sent via pipeline systems to the Bacton Gas Terminal on the coast of Norfolk for international distribution.
The initial total proven reserves of the Leman gas field were around 11 trillion ft³, with a production rate of around 200 million ft³/day.

Development

The Shell Leman 49/26A installation began production in August 1968. It had initial recoverable reserves of 292 billion m³. It is connected to the Shell terminal at Bacton. Leman 49/26B and 49/26B began production in November 1970. Leman 49/26C began in February 1972. Leman 49/26D began in August 1974. Leman 49/26E started in August 1983. Leman 49/26F and 49/26G began in September 1987. The Leman complex of platforms are connected to Bacton via Leman 49/26A, which is east of the Hewett complex. A decommissioned 36-inch pipeline formerly delivered gas from Leman 49/26BT to Bacton. Gas and condensate is piped to Bacton via Leman 49/26A Complex.
The installations developed by Shell were:

Installation	Location Block	Platforms	Function	Type	Legs	Well slots	Installed	Production start	Production to
Leman A Complex	49/26	Leman AD1	Drilling	Steel jacket	12	20	June 1967	August 1968
Leman A Complex	49/26	Leman AD2	Drilling	Steel jacket	4	3	September 1969	1970
Leman A Complex	49/26	Leman AP	Production	Steel jacket	12	–	August 1967	August 1968	Bacton, Leman BT
Leman A Complex	49/26	Leman AK	Compression	Steel jacket	8	–	February 1975	1975
Leman B Complex	49/26	Leman BD	Drilling	Steel jacket	12	24	June 1969	November 1970
Leman B Complex	49/26	Leman BP	Production	Steel jacket	8	–	December 1969	November 1970	Leman BT
Leman C Complex	49/26	Leman CD	Drilling	Steel jacket	12	20	1971	February 1972
Leman C Complex	49/26	Leman CP	Production	Steel jacket	8	–	1971	February 1972	Leman BT
Leman D platform	49/26	Leman D	Drilling, production and accommodation	Steel jacket	12	19	1971/3	September 1974	Leman BT
Leman E platform	49/26	Leman E	Drilling, production and accommodation	Steel jacket	6	10	January 1982	September 1983	Leman BP
Leman F platform	49/26	Leman F	Drilling, production and accommodation	Steel jacket					Leman AP
Leman G platform	49/26	Leman G	Drilling, production and accommodation	Steel jacket					Leman F
Leman BT BK BH Complex	49/26	Leman BT	Field terminal	Steel jacket	6	–	June 1970		Bacton
Leman BT BK BH Complex	49/26	Leman BK	Compression	Steel jacket	8	–	February 1975	1975
Leman BT BK BH Complex	49/26	Leman BH	Accommodation	Steel jacket	4	–	February 1981	–	–

The Shell Leman 49/26A complex also receives gas from the Corvette CV installation via a 36.6 km, 20-inch pipeline.
Block 49/27 of the Leman field is licensed to, and operated by, Perenco UK Ltd, originally by the Gas Council-Amoco. BP took over the interests of Amoco in 1998 and operated as BP-Amoco, subsequently BP. Perenco UK Ltd took over the interests of BP in the Leman and Indefatigable fields and BP plant at Bacton in 2003. The field had initial recoverable reserves of 292 billion m³. It comprises the following installations, platforms and complexes: Leman 49/27A ; 49/27B ; 49/27C ; 49/27D ; 49/27E ; 49/27F ; 49/27G; 49/27H; and 49/27J. Gas is routed to Bacton via two 30-inch pipelines from Leman 49/27A and Leman 49/27B.
The Leman installations developed by Amoco, now owned by Perenco, were:

Installation	Location Block	Platforms	Function	Type	Legs	Well slots	Installed	Production start	Production to
Leman A Complex	49/27	Leman AD	Drilling	Steel jacket	8	12	August 1967	Easter 1969	Leman AP
Leman A Complex	49/27	Leman AP	Production	Steel jacket	6	–	July 1968	Easter 1969	Leman AC
Leman A Complex	49/27	Leman AC	Compression	Steel jacket	8	–	1975	October 1976	Bacton
Leman A Complex	49/27	Leman AQ	Accommodation	Steel jacket	4	–	March 1984	–	–
Leman A Complex	49/27	Leman AX	Compression	Steel jacket			1988	1989	Leman AC
Leman B Complex	49/27	Leman BD	Drilling	Steel jacket	8	12	May 1968		Leman BP
Leman B Complex	49/27	Leman BP	Production	Steel jacket	6	–	August 1968
Leman B Complex	49/27	Leman BT	Field Terminal	Steel jacket	6	–	April 1970		Bacton
Leman C Complex	49/27	Leman CD	Drilling	Steel jacket	8	12	1967	1969
Leman C Complex	49/27	Leman CP	Production	Steel jacket	6	–	1967	1969	Leman AP
Leman D Complex	49/27	Leman DD	Drilling	Steel jacket	8	12	1972	1973
Leman D Complex	49/27	Leman DP	Production	Jack up	6	–	1973	1973	Leman BT
Leman E Complex	49/27	Leman ED	Drilling	Steel jacket	8	12	1972	1974
Leman E Complex	49/27	Leman EP	Production	Steel jacket	4	–	1974	1974	Leman AP
Leman F Complex	49/27	Leman FD	Drilling	Steel jacket	8	12	1973	1975
Leman F Complex	49/27	Leman FP	Production	Jack up	6	–	1975	1975	Leman BT
Leman G platform	49/27	Leman G	Production	Steel jacket		12	1985	October 1985	Leman BT
Leman H platform	49/27	Leman H	Production	Steel jacket	4	4	1984	1985	Leman J
Leman J platform	49/27	Leman J	Production	Steel jacket	4	4	1984	1985	Leman A

The Perenco Leman 49/27A complex also receives gas from the Camelot CA installation via a 14.5 km, 12-inch pipeline.
In the mid-1990s the glycol dehydration facilities of several installations in the Inde and Leman fields was decommissioned. This enabled the installations to become normally unattended installations reducing manning costs and the risks to personnel.

Production

The Leman gas composition and properties are as follows.

Composition	%
Methane	95.05
Ethane	2.86
Propane	0.49
i-butane	0.08
n-butane	0.09
i-pentane	0.03
n-pentane	0.02
Hexanes	0.02
Heptanes plus	0.04
Nitrogen	1.26
Helium	0.02
Carbon dioxide	0.04
Hydrogen sulphide	Nil
Total sulphur	<0.5

Gas gravity	0.585%
Mean condensate content	1.13 bbl/cubic foot
Btu rating	1024 Btu/ cubic foot

The annual gas production from the Shell Leman field was:The annual gas production from the Amoco Leman field was: