Analytical model for CO2 storage with fines migration, salt precipitation and partial miscibility

Well injectivity decline and low storage capacity can be a significant challenge to successful geological CO 2 storage in deep saline aquifers. Here we concentrate on formation damage induced by fines migration, salt precipitation and account for mutual brine-CO 2 solubility. Advancing water-gas menisci mobilise the reservoir fines; salt precipitates due to water evaporation into the injected CO 2 . We develop the mathematical model for two-phase flow accounting for fines migration, salt precipitation, and partial miscibility for water-CO 2 fluid and derive a novel analytical model for one-dimensional displacement of brine by CO 2 . The analytical model covers horizontal linear and radial flows, and linear flow in inclined reservoirs. We found that despite fines migration and salt precipitation yield well injectivity decline, it results in sweep efficiency increase. The most influential parameters on sweep and injectivity are the concentrations of detachable fines, salt drop-out and formation damage coefficients. The analytical model shows that the formation damage by fines migration and salt precipitation stabilises the displacement of brine by CO 2 by decreasing the mobility ratio on the displacement front, enhancing the CO 2 storage capacity. • Analytical model for 1D radial CO2 injection into aquifer • Accounting for fines migration, partial brine-CO2 miscibility and salt precipitation • Salt precipitant concentration is found from mass balance on full evaporation front • Fines migration and salt dropout decrease injectivity but improve sweep • Formation damage by fines migration decreases mobility ratio and stabilises flow