Stochastic layering effect on the upward migration ...

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XVI International Conference on Computational Methods in Water Resources (CMWR-XVI) Ingeniørhuset

Stochastic layering effect on the upward migration of anthropogenic CO2 sequestered in saline aquifers.
Paper
Author:Andrea Comerlati <andreac@dmsa.unipd.it> (University of Padova)
Alberto Bellin <alberto.bellin@ing.unitn.it> (University of Trento)
Massimiliano Ferronato <ferronat@dmsa.unipd.it> (University of Padova)
Giuseppe Gambolati <gambo@dmsa.unipd.it> (University of Padova)
Mario Putti <putti@dmsa.unipd.it> (University of Padova)
Pietro Teatini <teatini@dmsa.unipd.it> (University of Padova)
Presenter:Andrea Comerlati <andreac@dmsa.unipd.it> (University of Padova)
Date: 2006-06-18     Track: Special Sessions     Session: Geologic Sequestration of Carbon Dioxide
DOI:10.4122/1.1000000325
DOI:10.4122/1.1000000326

A widespread concern among the scientific community is the increase of the greenhouse gas emissions, especially CO2, which may yield an increase of earth's temperature. To reduce the CO2 released in the atmosphere an option which is attracting a growing attention is its sequestration in deep geologic formations. Deep saline aquifers may offer a great potential for the storage of large volumes of carbon dioxide. However, because of the relatively small practical experience with CO2 disposal in brine formations, more research is needed to assess the feasibility of the operation. In particular more studies are needed to identify aquifers sealed by continuous clay caprock over a regional scale. For this reason it is important to study the heterogeneous character of the sealing layers, i.e., the probability of having small fractures or zones of high permeability in the aquitards. In this paper we try to evaluate the effects of these potential heterogeneities on a CO2 sequestration problem. Aquitard properties are generated using a stochastic approach based on the binary field generation so that higher permeability inclusions are produced in the caprock with a given distribution. Montecarlo simulations are then needed to calculate the probability distribution of the escape of CO2 through a sequence of aquifer/aquitards that are representative of the Upper Adriatic system. Stochastic modeling appears to be a very powerful tool to take into account in a CO2 sequestration project the degree of continuity of the sealing aquitards. This issue is of importance to understand how potential discontinuities in the caprock can affect the upward migration of the injected carbon dioxide and to quantitatively assess the risk related to possible CO2 escape to the ground surface.