Reservoir engineering issues in the geological disposal of carbon dioxide

Injection into geological formations is one of the leading options for disposing of the large amounts of carbon dioxide generated in operations such as natural gas processing. A variety of factors influence the effectiveness of this form of storage in particular geological formations. The phase behaviour of carbon dioxide as a function of temperature and pressure is the most basic of these. Depending on the mineralogy, dissolution of the reservoir rock may lead to local changes in permeability in the short term, while precipitation reactions may influence the capacity for long term sequestration. The spread of the injected gas will also depend on the combined effect of viscous fingering, gravity override, the heterogeneity of the formation and the possibility of preferentially leaching out high permeability paths. The purpose of this work [as part of the Australian Petroleum Cooperative Research Centre's (APCRC's) GEODISC program] is to review the interaction between these factors and their integration in a coupled flow model, with a particular emphasis on the role of heterogeneity.