Carbon dioxide (CO2) geological storage potential of the Bass Basin

Abstract

Evaluation of the Bass Basin's suitability for CO2 storage has been undertaken by analysing several key basin analysis elements, including seal capacity and integrity, reservoir quality, petroleum systems modelling and CO2 migration and storage modelling. Seal geometry, capacity and integrity of the Demons Bluff Formation has been investigated to evaluate CO2 containment in the basin. The study revealed good to excellent sealing capacity for the Demons Bluff Formation and for the intraformational seals within the Eastern View Group (EVG). Faults traversing the reservoir/regional seal boundary, as well as faults intersecting the top of the regional seal were evaluated for future risk of reactivation. There is some risk of reactivation associated with N-E striking faults, fortunately these faults are mostly confined to the margins of the basin. Reservoirs of the Upper EVG generally have high porosity and permeability. Hydrocarbon migration and accumulation in the basin were simulated, to examine the petroleum potential of specific reservoirs within the basin. Migration models suggest most of the trapped hydrocarbons occur in the reservoir sands of the Middle EVG. Reservoirs of the Upper EVG were have received little hydrocarbon charge, except for the northeastern part of the basin. CO2 migration paths within reservoirs of the Upper EVG were simulated based on a buoyancy driven migration model. Migration pathways within the Upper EVG and CO2 accumulations under the regional seal were identified. In addition, total available pore volumes for CO2 storage associated with structural traps was calculated at > 2 billion m3. © 2011 Published by Elsevier Ltd.