Applicability of Vertically Integrated Models for Carbon Storage Modeling in Structured Heterogeneous Domains

Numerical modeling is an essential tool for investigating the potential of geologic carbon storage and evaluating storage sites. Many different modeling approaches can be applied to problems related to geologic carbon storage, with the choice of modeling approach usually based the type of questions being asked, available computational resources and familiarity with the approach. One option is the vertically-integrated modeling approach, where the three-dimensional governing equations of multiphase flow are integrated over the thickness of the formation. In this paper, we present initial results of a study investigating the applicability of vertically-integrated models for CO₂ and brine migration in the context of geologic carbon storage in heterogeneous domains. Results from a full three-dimensional model are compared to results from a vertically-integrated simulator for two test cases. One test case consists of a horizontally homogeneous, but vertically heterogeneous domain (i.e., a layered domain). The second test case has two intersecting vertically heterogeneous channels imbedded in a homogeneous background. The results show good agreement between the two approaches for both the depth-average CO₂ plume outline, as well as for the predicted vertical CO₂ saturation profiles. Overall, the results suggest that vertically-integrated modeling may be applicable for domains with vertical heterogeneity, such as formation created in fluvial deposition environments.