A geomechanical model for gas hydrate-bearing sediments

Abstract

Gas hydrate-bearing sediments are generally present in marine continental margins and permafrost sediments worldwide. Methane release from gas hydrate-bearing sediments may have a negative impact on greenhouse effects. Furthermore, methane hydrate deposits can lead to large-scale submarine slope failures, blowouts, platform foundation failures and borehole instability. Gas hydrates also constitute an attractive source of energy as they are estimated to contain very large reserves of methane. This paper presents a constitutive model to simulate the mechanical behaviour of methane hydrate-bearing soils based on the concept of an hierarchical single-surface (Hiss) framework. The core of the proposed model includes the Hiss critical-state framework, subloading concepts and hydrate enhancement factors. The performance of the model was found to be very satisfactory when compared against experimental data from triaxial tests based on natural and synthesised core samples involving different hydrate saturations, hydrate morphology and confinements.