Abstract:
To honor the Paris Agreement in decreasing greenhouse gas emissions, this thesis looks
into carbon dioxide (CO2) sequestration as an unavoidable path to lower these emissions
and limit rising global temperatures. After analyzing the subsurface characteristics of
more than fifty-one CO2 sequestration projects, two major problems seem to stir the
attention of the research community, notably storage low and heterogeneous
permeability conditions, and the destiny of injected CO2 over long periods.
Permeability, injection rate, and depth of storage are important indicators for the
longevity of the injection. Nevertheless, low permeability reservoirs have proven to be
very successful, notably with projects like Yanchang and CNPC Jilin in China (L.
Wang et al., 2017) having permeability in the order of 1 mD. We performed numerical
simulations using the TOUGH3 simulator, to assess the impact of permeability on the
CO2 sequestration process. The permeability range considered in this study is 0.1 to
1000 mD. On the other hand, five different heterogeneous structures were analyzed to
assess the impact of heterogeneity and permeability.
Injection scenarios involving injection over 30 years and 50 years, coupled with a post-injection observation over 1000 years were considered. CO2 occupied a percentage pore
volume ranging from 1 to 10% both benchmarked by the International Energy Agency
(IEA/EEC) report on CO2 Storage Capacity Assessment Methodologies for Saline
Aquifers (Gorecki et al 2009)
