Numerical Simulation of Interbedded Shale Failure in Oilsand Reservoirs by Electromagnetic Wave Excitation
Date
2019-09-13
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Abstract
This thesis work offers an exploratory study of selective heating and fracturing of a shale layer embedded into an oilsand material. A three phase (oil-water-steam) thermal-fluid flow formulation enriched with electromagnetic physics is developed to serve as a basic model to investigate whether selective heating is possible, and thereafter verify the mechanism of shale fracturing by solving a reservoir geomechanics problem. The finite element method is employed to solve numerically this highly nonlinear multiphysics (thermal/fluid/wave propagation) problem in porous media following a staggered scheme. This is coined as the EMTH (Electromagnetic-Thermo-Hydro) modeling framework. It has been found that the configuration of EM sources such as density in the form of interval distances between point-dipoles, and most importantly phase angle, control the electromagnetic field pattern and intensity that determine the efficacy of directing heating towards a specified target. The proper characterization of electrical properties of multiphasic-capillary-porous media is another outstanding issue to address for fully understanding the radiation and heating pattern of electromagnetic wave excitation. A synthetic reservoir geomechanics model for verifying the potential of fracturing is constructed and interfaced with the EMTH framework in a loosely coupled fashion. As such, the evolutions of temperature and pore pressure fields under electromagnetic excitation are treated as parametric inputs into the geomechanics model. Tensile failure within the interbedded shale as expected for fracturing is achieved at a specific combination of initial water/oil saturation setup. Other cases are investigated to help reveal a full image of correlations between electromagnetic excitation, temperature/pore pressure escalation, geomechanical constraints, and natural properties of reservoir.
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Keywords
finite element method, multiphase flow, electromagnetism, fracturing, multiphysics coupling
Citation
Shi, L. (2019). Numerical Simulation of Interbedded Shale Failure in Oilsand Reservoirs by Electromagnetic Wave Excitation (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.