Abstract

Ultra-soft soils on the deep water sea bed affects he infrastructure placed on it to produce the oil and gas. In this study, a very soft clay soils with shear strengths less than 1 kPa were prepared and the shear strengths were quantified using a modified vane shear and CIGMAT (Center for Innovative Grouting Materials and Technology)Penetrometer. Also, the electrical resistivity of the soft clays was correlated to the shear strengths so it can be used for better monitoring in field. In addition, three different types of model anchors (steel, concrete and plastic) were tested for pull-out strength using different displacement rates. Pull-out skin friction development at ultimate strength was dependent on the anchor material type and rate of pullout. Hyperbolic model has been developed to correlate pullout skin friction to the normalized displacement rate. Ultimate pull-out skin friction was correlated to the undrained shear strength of the soil. Finite element method was used to numerically model the experiments.

Keywords:
loading, undrained shear strength, cigmat penetrometer, vipulanandan, correlation, skin friction, bentonite content, shear strength, resistivity, upstream oil & gas
Subjects:
Offshore Facilities and Subsea Systems
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2015. International Society of Offshore and Polar Engineers
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