A preliminary numerical model of CO2 sequestration in a normally
consolidated sedimentary basin
A. Comerlati, G. Gambolati, M. Putti, P. Teatini
Dept. Mathematical Methods and Models for Scientific
Applications, University of Padova, Padova, Italy
ABSTRACT
A widespread concern among the scientific community is the
increase of the greenhouse gases, especially CO2, which may yield an
increase of earth's temperature. To reduce the CO2 emission into the
atmosphere an option which is attracting a growing attention is the
anthropogenic CO2 sequestration in deep geologic formations. Numerical
models help much in the design of the injection system, management and control
of the operations, and efficiency of the confinement. One major process to be
addressed is the dynamical simulation of the two phase flow
CO2-groundwater if CO2 is sequestered in deep saline aquifers.
Codes based on finite elements are developed to predict
a fundamental process underlying the CO2 subsurface confinement, i.e.
two-phase flow with dissolution of CO2 in the liquid phase.
Preliminary simulations of the injection from a point sink into a deep
aquifer located at about 1000 m depth in the normally consolidated sedimentary
Northern Adriatic basin shows the relative importance on the amount of the
sequestered CO2 of such factors as the actual nature of the gas (accounted
for by the CO2 supercompressibility), the formation anisotropy, the
injection pressure, the aquifer elastic storage and the CO2 solubility in
the groundwater. It turns also out the need for the accurate representation
of the dependence of the degree of saturation and the hydraulic conductivity
on the capillary pressure.
