--> The Discontinuity Layout Optimization Technique for SAGD Caprock Integrity Analysis

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The Discontinuity Layout Optimization Technique for SAGD Caprock Integrity Analysis

Abstract

Caprock integrity for reservoir containment is the key factor in determining if a SAGD can be used to extract in site bitumen. The common approach to determine caprock integrity is through a coupled (one way or two way) simulation where a reservoir simulation and mechanical simulation are used together and the stress state is assessed versus a failure criterion. This process is time consuming requiring expertise. The Discontinuity Layout Optimization (DLO) is a recently developed limit analysis procedure which provides a robust technique to solve the static geotechnical stability problems. With this new procedure, problems can be formulated entirely in terms of lines of discontinuity (e.g. slip or yield-lines). An extension of DLO towards factor of safety of the oil sands caprock is proposed in this paper, and the details of the DLO procedure is also presented. The performance of the DLO method is examined by a numerical simulation of a 2-D caprock integrity real case accomplished by using the traditional finite element method on a Mohr-Coulomb soil. The result shows that highly accurate solutions can be achieved, yet with less computing time.