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Modeling of coupled fluid-flow/geomechanical processes in stress-sensitive reservoirs has shown that different reservoir conditions yield different degrees of reservoir productivity reduction. Factors affecting the productivity of stress sensitive reservoirs include reservoir permeability, initial loading, aspect ratio, mechanical and physical properties of the reservoir and its surroundings, and fluid compressibility. The effects and interaction among these factors is complex and needs to be investigated if reservoir management is to be optimized. This study applies the statistical technique factorial design to investigate systematically and efficiently the interactions and effects that the above mentioned factors have on productivity index and cumulative production. To achieve these objectives, this study applies a 3D, finite difference, fully coupled, fluid-flow/rock deformation model.1 The model considers an inner and an outer domain representing the reservoir and its surroundings, respectively. The system is treated as a poro-elastic medium consisting of a deforming solid skeleton and a moving compressible pore fluid. Non-linear elastic deformation is assumed. Results indicate that the most important variables affecting reservoir productivity and cumulative production are reservoir permeability, aspect ratio, Young's modulus of the inner domain and fluid compressibility (the effect of fluid compressibility and Young's modulus of the inner domain are of the same order). This paper provides a deep discussion on the effect of these factors on both response variables: productivity index and cumulative production |
