CO2 for enhanced oil recovery in North sea chalk oil fields - can the CO2 be permanently stored?

The proposed project focuses on processes that may facilitate or endanger large scale permanent storage of CO2 injected to enhance oil recovery in Norwegian oil producing chalk fields. Recent results based on interpretation of the geological record, theor y and nanoscale experiments have established a new, emerging understanding of the chemistry and mechanics of chalk: High porosity chalks are protected from reaction with reservoir fluids by a passivating organic material. The chalk may be activated by por e fluid changes or by fracture growth due to stress changes and become highly reactive. This may result in rapid compaction and complete collapse of the reservoir and escape of stored CO2. The project details how to develop new fundamental knowledge by co mbining experiments, geological observations and computer simulations. The research will explicitly treat the state of passivation of calcite surfaces in the chalk matrix and focus on the detailed micro and nanoscale mechanisms of deformation and fluid-ch alk reactions. The development and proper application of this new fundamental knowledge can facilitate self healing of the reservoir chalk and ensure permanent storage of hundreds of Mton of CO2.