Influence of Spud-Can-Soil Interaction Modeling and Parameters on the Reliability Index of Neka Drilling Jack-Up Platform

Abstract

In the present study, the influence of spud-can-soil modeling and parameters on the reliability index of jack-up platform is investigated. Neka platform is studied as a case, which is a three-leg drilling jack-up type platform located in water depth of about 91 m in the Caspian Sea region. Various spud-can-soil interaction models such as pinned, fixed-base, hyperelastic, and nonlinear elastoplastic spud-can models are applied. The soil type is varied from loose to dense sand and also from soft NC clay to very stiff OC Clay. The effect of bias and coefficient of variation (COV) of the spud-can-soil interaction modeling and also the soil parameters such as the effective interface soil friction angle and also the undrained shear strength of clayey soil are studied. The results showed that inclusion of spud-can-soil interaction may have a considerable effect on the reliability of the jack-up platform. In particular, the bias and COV of soil have shown to have more significant effect on the reliability of jack-up platform in loose sand and soft clayey type soils. It is also found that bias in strength modeling of jack-up itself has less profound effect on the reliability index of the jack-up-foundation-soil system. Importance factors of spud-can-soil modeling are found to be quite considerable. The key aspect is that the inclusion of jack-up-spud-can-soil interaction is more crucial with respect to the reliability of jack-up platform than the choice of interaction model itself.