ORIGINAL CONSTRUCTION PROJECT
BUILDING THE INTERCONNECTOR

Work at the pipeline landfalls at Bacton in England and Zeebrugge in Belgium was completed over the 1996/7 winter period to minimise interference with recreational beach users. Each landfall comprised a cofferdam for the transition area between the sea and the beach and a winch platform above the high water mark containing all the equipment to provide the pulling force to bring the pipe string ashore.

At Bacton, a tunnel and shaft construction method was used to take the pipeline from the cofferdam to the clifftop where it is connected to the onshore line.

The Zeebrugge landfall site is adjacent to the “Fonteintjes” nature reserve which incorporates a fresh water lake. Here, the pipeline was installed beneath the reserve by directional drilling from the beach to the polder, which is below sea level. Key requirements were to avoid contamination of the fresh water lake and seepage of seawater into the polder. The onshore pipeline was then installed through the polder to the Zeebrugge terminal.

Dredging work started in December 1996 ahead of the pipelay. A total of two million cubic metres of material was removed by two of the largest and most modern trailing suction hopper dredgers in the world working in the open sea at water depths up to 60 metres. A further four million cubic metres was dredged in the approach to Zeebrugge where the route crosses the main sealane to Antwerp.

In March 1997 the deepwater semisubmersible laybarge Semac 1 anchored off Bacton. After the pipe had been successfully installed in the cofferdam, the Semac 1 laid 215 km of pipeline from Bacton to the tie-in point on the Belgian continental shelf.

At about the same time, the pipeline was pulled ashore from the flat bottomed shallow water laybarge Castoro 2 into the Zeebrugge cofferdam before laying 15 km out to the tie-in point.

Towards the end of May 1997 the Castoro 10 lifted the ends of both pipeline sections above water and performed the tie-in. After the weld was completed, it was tested and coated and the completed pipeline lowered on to the seabed. After laying, the pipeline was trenched into the seabed in order to minimise environmental impact and provide protection.

Preparatory work started at the Bacton compression facility in February 1997 and at the Zeebrugge reception terminal four months later. By May 1998 all major equipment had been delivered and the pipeline filled with low pressure gas. In August, gas was introduced into both terminals to enable commissioning to be carried out ready for start of operations in October 1998.

^^back to top

INTERCONNECTOR ACCESS
How to become a Shipper

TOOLS
Units converter
Site map

RSS feeds

|

LINKS
Related sites
Shippers