Prospective Saline Aquifer CO2 Storage Resource Estimates in Data Lean Regions

CO2 storage in geological formations is widely agreed to be a key carbon abatement technology. Whilst CO2 can be stored in depleted fields for which there will be abundant subsurface data to calculate storage resource, these calculations will be more difficult for saline aquifers which will often lack data since they may lie outside traditional petroleum systems considerations. Therefore, there is a two-fold challenge: Firstly, to screen for potential saline aquifer storage units rapidly and cost-effectively in any given basin close to point sources of CO2 production.Secondly, for those rock units so identified, to calculate the potential prospective storage resource (PSR) estimate (Mt CO2/km2), both at the gross fairway level and to high-grade areas within the fairway where storage resource is likely to be greatest, or where it meets given thresholds. Such calculations allow potential saline aquifers to be ranked within a region/basin, providing a focus for further data gathering and study. We have approached this problem by developing workflows for spatial screening that use simple regional geological parameters to identify suitable rock units, and then maximize limited subsurface data to provide an estimate of storage resource. To illustrate this approach, we have used the Cretaceous Shuaiba Formation of the Middle East as an example. The Shuaiba Formation is an established carbonate reservoir in super-giant fields such as Bu Hasa, Shaybah, and Safah (van Buchem et al., 2010; Droste, 2010). It includes bioherm, lagoonal, and more distal facies. Whilst within the industry there is abundant data concerning the Shuaiba Formation, we have limited ourselves to only the data available in the public domain – thus providing a proxy for genuinely data lean rock units. Furthermore, the results, whilst data limited, provide insight into the storage potential of the Shuaiba Formation which is likely to form a key CO2 storage unit in the Middle East.