Document Type
Article
Publication Date
9-1-2018
Abstract
Estimation of faults leakage potential is an essential component of CO2 storage integrity analysis. The selection of deep saline aquifers for CO2 storage in these settings mandates the modeling of fault-related fluid flow to estimate the most probable leakage rates. Faults usually have complex structures with heterogeneities and anisotropies over a range of scales because of which local capillary trapping becomes significantly important. We quantitatively investigate the implications of local capillary trapping for storage integrity and monitoring. Reservoir simulation results for a representative normal fault in a potential storage site in southern Louisiana with three possible damage zone configurations of homogenous, heterogeneous with fragmented core, and heterogeneous with intact core are presented. For each configuration, three cases are modeled to study the sensitivity of dissolution and local capillary trapping. Our results show that dissolution and local capillary trapping impede the upward migration of CO2, and may reduce leaked volume by more than 19% in some of the cases. It is also noted that presence of high permeability connected streaks may lessen the positive contributions of dissolution and local capillary trapping in reducing CO2 leakage. Moreover, capillary trapping significantly alters the pressure and saturation gradients locally and it may complicate monitoring strategies if extrapolation is required over larger length scales.
Publication Source (Journal or Book title)
International Journal of Greenhouse Gas Control
First Page
53
Last Page
61
Recommended Citation
Zulqarnain, M., Zeidouni, M., & Hughes, R. (2018). Implications of fault structure heterogeneities, dissolution and capillary trapping mechanisms for CO2 storage integrity. International Journal of Greenhouse Gas Control, 76, 53-61. https://doi.org/10.1016/j.ijggc.2018.06.013