Carbon dioxide sequestration in saline formations: Part I—Review of the modeling of solubility trapping

Sequestration of carbon dioxide in saline aquifers has emerged as the preferred method of permanently storing CO2 in subsurface formations because of the abundance and potential storage capacity of such sites. The key to the successful design and implementation of a sequestration operation is the ability to predict the spread of CO2 within the aquifer. This requires an understanding of the fundamental flow processes within a complex geologic environment that depend on the interaction of the trapping mechanisms related to capillarity, dissolution and mineralization. Due to the complex nature of this interaction, previous studies have dealt with the modeling of each of the trapping mechanisms individually, under idealized conditions. These studies have focused on the spread of the gravity current of supercritical CO2, enhanced dissolution due to natural convection and the process of mineralization involving the formation of carbonate precipitates. The objective of the current two part review is to provide a perspective on the progress made thus far towards the modeling of solubility trapping in part I and aspects of multiphase flow modeling related to CO2 sequestration in part II. The reviews are an attempt to facilitate the development of an integrated model for the prediction of practical problems as well as the identification of areas that need attention.