Applied Unsaturated Soil Mechanics in CO_2 Geo-Scquestration

摘要

Geo-sequestration (geological sequestration) is showing us the enormous potential of permanently storing CO_2 underground to reduce greenhouse gas emission from fossil fuels. Hydro-mechanical evaluations of the storing formations are essential to such CO_2 geo-sequestration projects. This paper focuses mainly on studying relationships between CO_2 saturation and pore pressure change of rocks during the dilatation process. In order to investigate how much the injected CO_2 can influence the pore pressure change of rocks when the dilatation phenomena happen, rock samples were treated with CO_2 saturated water under triaxial high pressure and compressive experiment conditions. In this paper, a time dependent porosity method was firstly put forward to study the dilatation process of rocks, and it was successfully implemented by a finite element method associated with multiphase characteristics. The results show that CO_2 saturated water plays a key role in the acceleration of dilatation process of rocks. The dissipation of pore pressure is seriously controlled by the porosity magnitude of rocks. If the rock has larger magnitude of the porosity, the rock behaves fast dissipation of the pore pressure.