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Advances in Civil Engineering
Volume 2018, Article ID 1474320, 13 pages
https://doi.org/10.1155/2018/1474320
Research Article

Coupled Geomechanical-Flow Assessment of CO2 Leakage through Heterogeneous Caprock during CCS

Department of Earth Resources and Environmental Engineering, Hanyang University, Seoul 04763, Republic of Korea

Correspondence should be addressed to Kun Sang Lee; rk.ca.gnaynah@eelsnuk

Received 28 August 2017; Accepted 8 January 2018; Published 28 February 2018

Academic Editor: Arnaud Perrot

Copyright © 2018 Guan Woo Kim et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The viability of carbon capture sequestration (CCS) is dependent on the secure storage of CO2 in subsurface geologic formations. Geomechanical failure of caprock is one of the main reasons of CO2 leakage from the storage formations. Through comprehensive assessment on the petrophysical and geomechanical heterogeneities of caprock, it is possible to predict the risk of unexpected caprock failure. To describe the fracture reactivation, the modified Barton–Bandis model is applied. In order to generate hydro-geomechanically heterogeneous fields, the negative correlation between porosity and Young’s modulus/Poisson’s ratio is applied. In comparison with the homogeneous model, effects of heterogeneity are examined in terms of vertical deformation and the amount of leaked CO2. To compare the effects of heterogeneity, heterogeneous models for both geomechanical and petrophysical properties in coupled simulation are designed. After 10-year injection with petrophysically heterogeneous and geomechanically homogeneous caprock, CO2 leakage is larger than that of the homogeneous model. In contrast, heterogeneity of geomechanical properties is shown to mitigate additional escape of CO2. Vertical displacement of every heterogeneous model is larger than homogeneous model. The model with compressive tectonic stress shows much more stable trapping with heterogeneous caprock, but there is possibility of rapid leakage after homogeneous caprock failure.