Production/injection induced geomechanical issues in petroleum operations have been gaining more and more emphasis recently. Realistic modeling, monitoring, and controlling of flow-induced stresses are essential (and also present challenge) to reservoir management. This paper presents a numerical 2D finite-difference model incorporating the complex thermal/fluid-flow/geomechanical interactions. Non-isothermal effect (e.g., a cold-water flooding) is emphasized.

The paper describes (i) model development, (ii) model verification, (iii) simulation results, and (iv) practical implications and model limitations. Governing equations (heat flow, rock elastic deformation, and fluid flow) and the associated initial/boundary conditions are described. Control-volume-based numerical discretization/algorithm is outlined. Published analytical solutions are compared to verify the model. Effects of thermal and fluid-flow (pressurization) are isolated to show the relative importance of each mechanism.

Compared to the conventional isothermal or thermal reservoir simulators, describing flow- and thermal-induced evolution/distribution of reservoir stresses is the unique feature of the presented simulator. Simulation results indicate that thermal-induced stresses can alter reservoir stress anisotropy (in both magnitude and direction). The principal implication is that alteration and reorientation of permeability anisotropy could occur by two potential stress mechanisms: (i) permeability reduction by pore-volume compressibility effect, and (ii) permeability enhancement by flood-induced fracturing. Future work is to study the impact of the altered permeability on the sweep and recovery of a flooding project.

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