Impact of capillary pressure on permeability impairment during CO2 injection into deep saline aquifers
来源期刊：中南大学学报(英文版)2013年第8期
论文作者：WANG Yuan(王媛) 刘阳
文章页码：2293 - 2298
Key words：permeability impairment; solid precipitation; capillary pressure; back flow; characteristic parameters
Abstract: During CO2 injection in deep saline aquifers, salt precipitation happens around the injection well because of capillary driven back flow, inducing permeability impairment. The permeability impairment affects CO2 injectivity and migration. Different values of three characteristic parameters for capillary pressure function (air entry pressure, empirical parameter m and liquid residual saturation) as well as input absolute value of maximum capillary are chosen in numerical simulation to figure out their effects on salt precipitation. Verma & Pruess model is then used for quantifying permeability impairment. Results show that permeability decreases with higher air entry pressure, larger liquid residual saturation, and especially smaller value of empirical parameter m. To enhance CO2 injectivity and avoid blocking of CO2 migration, a homogenous formation with large pore size should be chosen before CO2 injection into deep saline aquifer.
WANG Yuan(王媛)1, 2, LIU Yang(刘阳)1, 2
(1. Key Laboratory for Geomechanics and Embankment Engineering of Ministry of Education (Hohai University),
Nanjing 210098, China;
2. College of Civil and Transportation Engineering, Hohai University, Nanjing 210098, China)
Abstract:During CO2 injection in deep saline aquifers, salt precipitation happens around the injection well because of capillary driven back flow, inducing permeability impairment. The permeability impairment affects CO2 injectivity and migration. Different values of three characteristic parameters for capillary pressure function (air entry pressure, empirical parameter m and liquid residual saturation) as well as input absolute value of maximum capillary are chosen in numerical simulation to figure out their effects on salt precipitation. Verma & Pruess model is then used for quantifying permeability impairment. Results show that permeability decreases with higher air entry pressure, larger liquid residual saturation, and especially smaller value of empirical parameter m. To enhance CO2 injectivity and avoid blocking of CO2 migration, a homogenous formation with large pore size should be chosen before CO2 injection into deep saline aquifer.
Key words:permeability impairment; solid precipitation; capillary pressure; back flow; characteristic parameters
