Rock placement

Rock placement | Oil & gas

DEME Offshore is one of the world’s leading experts in subsea rock placement. Our high-tech DP2 subsea fallpipe vessels are the plant of choice and the fleet has a capacity for precision work and super smooth levelling abilities in depths in excess of 2,000 m. Rock placement is very accurate and we can operate in sea states of up to 3.5 m significant wave height.

Scour protection: absolutely sure
Pipeline related services include scour protection, pipeline protection / stabilisation against anchor damage or trawler boards, upheaval buckling prevention and the insulation of pipelines.

State-of-the-art ROV
Rock placements are executed with extremely high precision, even in extreme water depths. Therefore, an active heave-compensated Remote Operated Vehicle (ROV) is fixed below the fallpipe (vertical movement +/- 10 cm), facilitating precision steering.

Rock placement for renewables
DEME Offshore’s DP fallpipe vessels take positions close within 5 to 10 m of a wind turbine to carry out the job with high accuracy. If a wind farm incorporate 150 wind turbines, we do the trick 150 times in the same precise and safe way.

Safe and accurate
Rock placement calls for special skills and for intelligent modifications and innovations because every location is different, even in the North Sea. That is how we developed the Inclined Fallpipe system. Imagine a fallpipe that protrudes with an angle from the rear of the vessel. The rocks are then placed in the precise location directly next to the wind turbine foundation in an extremely controlled manner. That’s innovative. 

The same goes for our levelling-tool. Suspended beneath the ROV, this tool creates super smooth levelled areas of rock needed for installing concrete gravity based foundations.

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