Rock has been used for ports and coastal protection purposes for centuries – for dikes and breakwaters, groins and scour protection. Yet in the past several decades the uses of rock have taken on new dimensions in the execution of maritime infrastructure construction.
Previously referred to as rock dumping, today the term Subsea Rock Installation is more common, reflecting the advanced techniques that are being applied, in particular for the offshore oil and gas sector.
Two types of Subsea Rock Installation are distinguished: One for shallow water, up to 50 metres water depths, typically used for coastal and embankment protection works and for scour protection for offshore oil, gas and wind energy developments. The other at greater water depths, usually ranging from 50 to as deep as 2200 metres. This deep-sea rock installation is primarily used for pipeline and cable protection and stabilisation.
This newest Facts About describes these two types of Rock Installation, examining the specialised techniques and equipment like the SSDV (side-stone dumping vessel) vs. the DP-FFPV (dynamically positioned flexible fall pipe vessels), ROVs (remotely operated vehicles) and DGPS. The crucial role which dredging contractors play in Subsea Rock Installation for the offshore oil and gas industry is given special attention.
Good engineering practice considers the environmental conditions, technical feasibility and costs in order to select the most efficient and economical solution. The success of Subsea Rock Installation after three decades of use demonstrates that it is a competitive and reliable method to protect subsea structures and ensure their integrity from damages caused by waves, currents and human activities.
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Press release, September 4, 2012; Image: DONG Energy