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Article
Challenging Geostatistical Methods to Represent Heterogeneity in CO2 Reservoirs Under Residual Trapping
Environmental and Engineering Geoscience
  • James R. Damico
  • Robert W. Ritzi, Wright State University - Main Campus
  • Naum I. Gershenzon, Wright State University - Main Campus
  • Roland T. Okwen
Document Type
Article
Publication Date
12-1-2018
Abstract

Geostatistical methods based on two-point spatial-bivariate statistics have been used to model heterogene­ity within computational studies of the dispersion of con­taminants in groundwater reservoirs and the trapping ofCO2 in geosequestration reservoirs. The ability of these methods to represent fluvial architecture, commonly oc­curring in such reservoirs, has been questioned. We challenged a widely used two-point spatial-bivariate sta­tistical method to represent fluvial heterogeneity in the context of representing how reservoir heterogeneity af­fects residual trapping of CO2 injected for geosequestra­tion. A more rigorous model for fluvial architecture was used as the benchmark in these studies. Both the geo-statistically generated model and the benchmark model were interrogated, and metrics for the connectivity of high-permeability preferential flow pathways were quan­tified. Computational simulations of CO2 injection were performed, and metrics for CO2 dynamics and trapping were quantified. All metrics were similar between the two models. The percentage of high-permeability cells in spanning connected clusters (percolating clusters) was similar because percolation is strongly dependent upon proportions, and the same proportion of higher per­meability cross-strata was specified in generating both models. The CO2 plume dynamics and residual trapping metrics were similar because they are largely controlled by the occurrence of percolating clusters. The bench­mark model represented more features of the fluvial ar­chitecture and, depending on context, representing those features may be quite important, but the simpler geosta­tistical model was able to adequately represent fluvialreservoir architecture within the context and within the scope of the parameters represented here.

DOI
10.2113/EEG-2116
Citation Information
James R. Damico, Robert W. Ritzi, Naum I. Gershenzon and Roland T. Okwen. "Challenging Geostatistical Methods to Represent Heterogeneity in CO2 Reservoirs Under Residual Trapping" Environmental and Engineering Geoscience Vol. 24 Iss. 4 (2018) p. 357 - 373 ISSN: 1078-7275
Available at: http://works.bepress.com/naum_gershenzon/72/