A Multiscale Thermo-Mechanical Framework for Geothermal Energy Applications

Abstract

Natural rocks in geothermal energy reservoir are heterogeneous and consist of fractures, solid and fluid phases that form complex structures at multiple scales. Explicit incorporation of multiple scales of fractures and heterogeneities into large-scale tightly coupled models is impractical and would cause tremendous computational costs. Therefore, efficient multi-scale and multi-physics strategies are necessary for capturing sub-grid-scale processes and their impacts on macroscopic behavior. In this work, we present a multiscale framework for coupled thermo-mechanical behavior of rocks in geothermal reservoir. The proposed approach allows for separate micro-constitutive laws, which provides an efficient way of capturing both large- and small-scale processes. The performance of the modeling framework in simulation of geothermal energy reservoir is demonstrated through numerical examples.