Towards Maximum Utilization of CO2 Storage Resources

AbstractLarge scale deployment of CO2 capture and storage (CCS) has the potential to be an important part of the effort to mitigate climate changes. If large scale CCS is to be realised the storage resources of saline aquifers should be utilised to their full potential by maximising the storage performance of each aquifer. This can not be performed without water production to control and relieve the induced pressure increase from CO2 injection. Large scale CO2 injection with a large number of injection wells will hence require a large number of water production wells. For offshore aquifers wells are one of the main cost drivers and pressure control by water production in CO2 storage operations will increase the number of wells. However, water production will also utilize storage resources better, reduce the area of impact and hence reduce the need for monitoring, give better control on the sub-surface by the increased numbers of observation points and may reduce the future liability of the operator. This study investigates strategies for optimal design of well patterns, inter-well distances, optimal injection rates and average injection period for each well as function of storage characteristics such as areal size, thickness, porosity and safe pressure increase. The main focus is on inverted five spot well patterns in tilted reservoirs and the asymmetry in well positions required due to the tilting. Much of the work is based on simulations reported for similar well patterns in models without tilt in an accompanying paper which will be presented at this conference [1]