Elevated pore pressures, commonly encountered in the shallow, unconsolidated section of the sedimentary column, present a significant hazard during the drilling and completion of offshore wells. The porosity of the ocean-floor sediments is high and a cover of low-permeability clay can prevent the underlying sediments from draining, even at very shallow depths below the seafloor. As further deposition loads the sediment, the entrapped fluids impede normal compaction by becoming pressurized. The lowered effective stress that results from the higher pore fluid pressure produces a proportional drop in the strength of non-cohesive sediments, resulting in very weak shallow sands. This weakness...

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