Appraisal of global CO2 storage opportunities using the geomechanical facies approach

Abstract

Different tectonic settings exert different depositional process controls within the tectonic basin which influence CO2 storage site suitability in terms of basin architecture, caprock architecture, reservoir quality, stress state, mechanical characteristics, fractures, burial depth, geothermal gradient, risk of orogenic modification, structural stability and preservation potential. We apply the concept of geomechanical facies; where deposits are grouped together on the basis of engineering parameters that fulfil a specific role within the storage system, e.g. reservoir, caprock, overburden; to provide an assessment of CO2 storage suitability for seven different tectonic settings. The geomechanical facies data were analysed using two different multiple attribute decision analysis methodologies and the results show that foreland basins are likely to be the most suitable for CO2 storage, followed by passive continental margins, terrestrial rift basins, Strike-slip basins, Back-arc basins, with oceanic basins, forearc basins and trench basins expected to be the least suitable. The geomechanical facies approach was compared with two current storage projects (Sleipner and In Salah) and a natural CO2 storage analogue (Miller) to build confidence in the methodology. Finally the global distribution of the most likely CO2 storage basins based on their geomechanical facies was mapped and correlated with CO2 emission sources.