L4-L7 gas fields
| L4-L7 gas fields | |
|---|---|
| Country | Netherlands |
| Region | North Sea |
| Location/blocks | L4 and L7 |
| Offshore/onshore | Offshore |
| Coordinates | 53°32′18″N 04°12′9″E / 53.53833°N 4.20250°E |
| Operator | Petroland BV, then Total |
| Owner | Petroland BV, then Total |
| Field history | |
| Discovery | 1973 |
| Start of production | 1977 |
| Peak of production | 135 MMSCFD |
| Production | |
| Recoverable gas | 1,470×109 cu ft (42×109 m3) |
The L4-L7 gas fields are significant natural gas producing fields in the Netherlands sectors L4 and L7 of the North Sea. They are operationally one complex which started producing gas from the L7 main platform hub in 1977 and was still partly operational in 2021.
The fields
[edit]The adjacent Block L4 and L7 gas fields are located in the Southern North Sea.[1][2] The L7 gas field was discovered in 1973 and the L4 field the following year.[3] The gas reservoirs are Upper Rotliegendes sandstones, L7 lies at a depth of 12,700 feet (3,900 metres).[4] The L7 field had recoverable reserves of 1.47 trillion cubic feet.[3]
Development
[edit]The L4-L7 reservoirs were developed by a number of offshore installations across both Blocks. The L7 main platform complex was the hub of the fields, it received gas from its bridge-linked drilling/wellhead (C) and compression (PK) platforms, from L7 Block satellite platforms, and from the adjacent Block L4.[3][5][6]
| Installation | Coordinates | Water depth | Platform | Function | Type | Legs | Well slots | Installed | Production start | Production to | Status |
|---|---|---|---|---|---|---|---|---|---|---|---|
| L7 main platform complex (bridge linked) | 53°32’18”N 04°12’9”E | 27.5 m | L7-C Platform | Drilling, production | Steel jacket | 4 | 6 | April 1976 | June 1977 | L7-P | Closed |
| L7-P Platform | Processing | Steel jacket | 8 | – | 1976 | June 1977 | L10 platform by 5.8 km 16-inch pipeline | Closed May 2017 | |||
| L7-Q Platform | Accommodation | Steel jacket | 4 | – | 1976 | – | – | Closed | |||
| L7-PK Platform | Compression | Steel jacket | 4 | – | June 1982 | 1983 | L7-P | Closed May 2017 | |||
| L7B Complex | 53°36’32”N 04°12’24”E | 34.7 m | L7-B Platform | Drilling, production | Steel jacket | 4 | 6 | July 1975 | 1977 | L7-P by 7.85 km 12-inch pipeline | Closed |
| L7-BB | Wellhead platform | Steel jacket | 4 | 6 | September 1978 | 1979 | Closed | ||||
| L7A Satellite | 53°36’01”N 04°05’01”E | 34.5 m | L7-A Platform | Drilling, production | Steel jacket | 4 | 2 | August 1984 | Late 1985 | L7-P by 9.8 km 10-inch pipeline | Closed |
| L7-H | 53.626389°N 4.144967°E | 36 m | L7-H Platform | Wellhead platform | Fixed steel | 1989 | Closed | ||||
| L7-N | 53.573944°N 4.176776°E | 32 m | L7-N Platform | Wellhead platform | Fixed steel | 1988 | Wells plugged 2015 | ||||
| L4-A | 53°43’32”N 04°05’56”E | 39.5 m | L4-A Platform | Drilling, production, accommodation | Steel jacket | 8 | 6 | Summer 1982 | 1983 | L7-P by 22.7 km 12-inch pipeline | Operating |
| L4-B | 53°40’36”N 04°00’06”E | 38.7 m | L4-B Platform | Drilling, production | Steel jacket | 4 | 2 | August 1984 | Late 1985 | L7-A by 10.6 k, 10-inch pipeline | Wells plugged 2015 |
| L4-G | 53.81009°N 4.15805°E | 42 m | L4-G | Wellhead | Subsea wellhead | 2006 | Operating | ||||
| L4-PN | 53.82341°N 4.0498°E | 41 m | L4-PN Platform | Production | Fixed steel | 1998 | Operating |
The peak production from the L7 field was 135 MMSCFD in 1978–9, and from the L4 field was 106 MMSCFD in 1983.[3] The design capacity of the process facilities on L7-P platform is 5.5 million m3/day.[3]
The field was initially operated by Petroland BV, then Total.[3][6]
Decommissioning
[edit]The status of the production facilities is given in the final column of the above table. The entire L7 field is now closed as is the L4-B Platform. Operations continue in parts of the L4 field.[6]
See also
[edit]- Helder, Helm and Hoorn oil fields
- Kotter and Logger oil and gas fields
- K13 gas fields
- K14-K18 gas fields
- L10 gas field
References
[edit]- ^ "Dutch Offshore Gas: a success story". Retrieved 10 October 2021.
- ^ Department of Trade and Industry (1994). The Energy Report. London: HMSO. pp. Map 3. ISBN 0115153802.
- ^ a b c d e f Oilfield Publications Limited (1985). The North Sea Platform Guide. Ledbury UK: Oilfield Publications Limited. pp. 423–33.
- ^ "Fact sheet L7" (PDF). Retrieved 10 October 2021.
- ^ "L7 gas fields". barellfull. Retrieved 10 October 2021.
- ^ a b c OSPAR (2017). "North Sea Offshore Installations". OSPAR. Retrieved 10 October 2021.