Fracturing of shales via in-situ pore fluid pressurization by electromagnetic heating

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The research project relates to unconventional oil extraction with a focus on new technologies to limit the use of water in the in-situ recovery of oil from heterogeneous oil sand reservoirs containing interbedded shales. Interbedded shales are large lateral clay-like intrusions interspersed within the oil sand reservoir that hinder the propagation of steam in SAGD (Steam Assisted Gravity Drainage), and hence oil production. Inducing the failure of shale by steam injection would require high pressures and considerable water usage because of low permeability of the material. Instead, the water within the shale is thermally excited by penetration of an electromagnetic (EM) wave just as when cooking food in a domestic microwave oven. The main objective of the research is to develop a method for fracturing the shales and adjacent oil sand using an electromagnetic in-situ heating scheme that induces thermal pressurization of the pore fluid and frees up the unbound water from the clay particles. This will be achieved following an integrated approach involving lab experimental, constitutive and numerical modelling works through: (1) Understanding of thermo-poro-mechanical behaviour of shales in the presence of electromagnetic waves at three scales, i.e. macro-, meso- and micro-scales, (2) Lab triaxial testing in order to reproduce the in-situ pore fluid pressurization in a shale sample subjected to EM wave via an internal probe, and (3) Multi-scale numerical modelling of the fracturing phenomenon and implementation into a computational code to model the process at the reservoir scale. A granular description of shale will be used in which stacked clay platelets at the nano-scale form sub-micron clay aggregates grains that interact with each other through both short- and long-range forces. The proposed research will be undertaken in close collaboration with several leading industry partners in Calgary, namely, Computer Modelling Group Ltd., Imperial Oil Ltd., Husky Energy, and BitCan Inc. CMG Reservoir Simulation Foundation has also committed to financially support this strategic project.