Foundation design challenges of the MCR-A skirted gravity platform

The MCR-A platform is a skirted gravity base platform to be installed in the Caspian Sea offshore Turkmenistan in ground conditions composed of stiff clay Advanced 3D numerical analysis was required to adequately model the annular geometry and high environmental loading on the substructure. High suction pressures are needed to install the skirts to the depth necessary for foundation stability. The high suction pressures required a complex skirt stiffener arrangement and this posed challenges in quantifying the penetration resistance to be overcome in order to ensure the required skirt penetration could be achieved. In addition, the presence of spudcan footprint 'craters' in the direct vicinity of the platform resulting from previous jack-up operations required special design consideration. The approaches carried out to overcome these geotechnical design challenges are described in this paper.