Hydro services starts gas boring in the Netherlands

Hydro Soil Services NV (HSS), port and marine engineering specialist in the global DEME Group, has completed a rare double directional drilling for a pipeline which will connect the gas network of The Netherlands with gas produced in the UK.

Despite encountering surprising ground conditions, HSS drilled two 28-inch horizontal bores, each 1,250m long, from a man-made island in the centre of the Westerschelde river, between Belgium and the Netherlands, within the project's six-week schedule.

Difficulties arose when the bore heading north-east from the island met a 100m-long stretch of ground, 10m below the river bed, containing heavy timbers. The wooden beams, up to 15 cm square in cross-section, have not yet been identified but an early theory is that they are the remains of a settlement covered long ago by a change in the course of the river.

DEME Group partner Dredging International (DI) began the project in March by building the central cofferdam, using steel piles positioned by cranes mounted on the pontoon barges Diabolix and Bever, and material reclaimed by dredging from the river bed. HSS's large self-elevating platform, the Zeebouwer, was then attached to the 80m by 28m cofferdam to carry the drilling rigs.