# L4-L7 gas fields

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

The adjacent Block L4 and L7 gas fields are located in the Southern North Sea. The L7 gas field was discovered in 1973 and the L4 field the following year. The gas reservoirs are Upper Rotliegendes sandstones, L7 lies at a depth of 12,700 feet (3,900 metres). The L7 field had recoverable reserves of 1.47 trillion cubic feet.

## Development

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.
L4-L7 Fields Offshore installations :
| 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 main platform complex (bridge linked) | 53°32’18”N 04°12’9”E | 27.5 m | L7-P Platform | Processing | Steel jacket | 8 | – | 1976 | June 1977 | L10 platform by 5.8 km 16-inch pipeline | Closed May 2017 |
| L7 main platform complex (bridge linked) | 53°32’18”N 04°12’9”E | 27.5 m | L7-Q Platform | Accommodation | Steel jacket | 4 | – | 1976 | – | – | Closed |
| L7 main platform complex (bridge linked) | 53°32’18”N 04°12’9”E | 27.5 m | 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 |
| L7B Complex | 53°36’32”N 04°12’24”E | 34.7 m | 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. The design capacity of the process facilities on L7-P platform is 5.5 million m$^3$/day.
The field was initially operated by Petroland BV, then Total.

## Decommissioning

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.