Geotechnical aspects of recovery processes in oil sands

Abstract

The geomechanical aspects of oil sand behaviour are important for the understanding of the thermal processes for bitumen recovery from oil sands. The paper describes the study of the geomechanical response of oil sand to fluid injection, which causes formation parting in oil sands. The behaviour of constitutive models in the low effective stress range is examined, and it is shown by modelling that the frictional properties at low effective stress control the development of the failure zone around injection wells and fractures. Based on the matching of laboratory data for the PetroCanada–CanOXY–Esso–JACOS (PCEJ) project, a generalized hyperbolic model is proposed. Modelling of a field design involving horizontal fracture shows that the stress paths and the amount of dilation experienced by the formation can be very different from those measured in standard laboratory tests. Laboratory measurements should be done at the very small stresses and along the stress paths expected in the field. These can be predicted by modelling. Key words : oil sands, constitutive models, fluid injection, hyperbolic model, sand dilation, horizontal fracture, oil sands modelling, bitumen recovery, sand failure.