Safe pipeline construction, improved environmental outcome

The implementation of the technically complex pipeline construction concept developed by geologists, engineers and environmental experts was completed on schedule and was in full compliance with the strict environmental requirements imposed on the project teams engaged in this project in the Schleswig-Holstein Tidelands National Park.

2005: Trench in which the pipeline is to be laid  

On the ocean side, two 7.5-kilometre stainless steel pipelines were laid from the dike line at Friedrichskoog-Spitze through the tidal flats off the coast and on to Mittelplate Island. Behind the dike, the pipelines were extended over distance of approx. 2.8 kilometers to the Dieksand Land Station. One pipeline with a diameter of 250 mm is provided for transporting the crude oil from the island, and the second pipeline, with a diameter of 150 mm, serves as a return line for the reservoir water extracted in the water separators at the Land Station. On the island, this reservoir brine is re-injected into the reservoir to maintain internal pressure.

The pre-fabricated sections of submarine pipelines were drawn into two parallel horizontal boreholes drilled beforehand, with the entire offshore distance being divided into six sections.
The pipeline was buried at depths of up to 20 meters.
These depths are sufficient to allow the pipelines to pass safely underneath the tideways as well as the dike. Inside the six construction pits along the pipeline route, the piping runs were welded together at a depth of five meters.

The technical concept for laying the pipelines by means of directional horizontal drilling technologies confined the impact of construction on the tidal flats to a minimum. All construction activities out on the tidal flats, including de-installation along the pipeline route, as well as the pipeline construction of the onshore component and the connection of the pipelines to the Dieksand Land Station, were completed successfully and on time.
The pipeline went into operation at the end of October 2005.