Geomechanical constitutive modelling of a chalk partly saturated by oil and water

Chalk in oil reservoir is generally saturated by two or more different fluids. In this paper, a constitutive law is proposed for the modelling of the mechanical behaviour of a chalk. The effects of the capillary pressure are taken into account. They are considered as an independent variable, as in the Barcelona’s basic model developed for unsaturated clay. On the other hand, internal friction and pore collapse are modelled as independent mechanisms. Eventually, the model predictions are compared with experimental results.