Case Study: Offshore Windfarm Cable Ducts

Project Summary

AMS were commissioned to design and install the 2 cable landfall ducts form a cliff top compound required as part of the a Windfarm project in Aberdeen.

Prior to any works being undertaken a detailed mobilisation assessment was required due to the significantly restricted access available.

The scheme comprised the drilling and installation of the two cable ducts from a cliff top 20m above the north sea, exiting on the sea bed 550m offshore, 10m beneath mean low water level, Ground conditions consisted of Granite and Schist Rock formation with 4m of loose material above the bedrock on the seabed.

Both pilot drills were stopped short of punching out on the seabed to reduce fluid losses into the marine environment. Each pilot was then upsized to 20” using forward reaming techniques and flushed with water to drilling fluid before final punch out was carried out.

The pipes were proved and pigged onshore and fitted with a dynema rope before being capped and ballasted with water to reduce friction during the pipe pushing installation process. Drilling and duct  installations were completed ahead of programme

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Pipe pushing in progress
Pipe pushing in progress
Drill site overview
Drill site overview
Prime Drilling PD250 250t Drill Rig in position
Prime Drilling PD250 250t Drill Rig in position
Drilling in progress
Drilling in progress