Poro-mechanical modeling of CO2 sequestration on exploited gas fields
M. Ferronato, G. Gambolati, C. Janna, P. Teatini
Dept. Mathematical Methods and Models for Scientific
Applications, University of Padova, Padova, Italy
ABSTRACT
Injection of CO2 in an exploited faulted gas field is simulated
with the aim at investigating the poro-mechanical consequences of the
sequestration. A long-term injection until the initial reservoir pressure
is exceeded by as much as 40% over a period of 150 years is addressed. The process
is analyzed from a poro-mechanical point of view using a FE-IE
(Finite Element-Interface Element) model. The results show that the ground
surface rebound due to the overpressure generated by the CO2
storage partially mitigates the land subsidence experienced by the
area because of the previous gas field depletion. Activation of faults
lying close to the reservoir boundary occurs before being reached by the
CO2 plume, so there is little chance for a CO2 escape.
The caprock is shown to preserve its integrity with the shear stress
approaching the limiting state prone to the rock failure on a local scale
only, thus not jeopardizing the overall effectiveness of the sequestration.
