Integration of the comprehensive Gorgon CO₂ surveillance program for history matching of the Dupuy reservoir model

Abstract

The Gorgon CO₂ project (The Gorgon Project is operated by Chevron Australia and is a joint venture of the Australian subsidiaries of Chevron (47.3%), ExxonMobil (25%), Shell (25%), Osaka Gas (1.25%), Tokyo Gas (1%) and JERA (0.417%)) is the world’s largest operational Carbon Capture and Storage (CCS) project dedicated to greenhouse gas abatement. Since starting injection in 2019 it has successfully sequestered more than 7.5 million tonnes of CO₂ equivalent (as at 31 January 2023). A comprehensive surveillance program – including reservoir pressure monitoring, 4D seismic, microseismic monitoring, distributed temperature and acoustic sensing, and InSAR surface displacement measurement – provides a wealth of data for developing history-matched static, dynamic and geomechanical models that are instrumental in the operation and development planning of the field. In comparison to modelling of conventional hydrocarbon reservoirs, in which maximising production and ultimate recovery are typically the focus, developing and selecting a suite of representative CCS models requires consideration of an additional set of factors. These factors include modelling CO₂ plume movement, managing reservoir pressure at key locations and accommodating geomechanical constraints. This paper will explore these differences, and how the various sources of surveillance data have been integrated into the modelling process to better understand and predict the dynamic behaviour of the Dupuy reservoir.