http://www.sciencedirect.com/science/article/pii/S175058361500184X
Modelling CO2 migration in aquifers; considering 3D seismic property data and the effect of site-typical depositional heterogeneities Anja Sundal Rohaldin Miri Per Aagaard Highlights • Recent 3D seismic data and a revised geological model for The Johansen Fm., North Sea Norway form the basis for new models and reservoir quality evaluation for CO2 storage. The Johansen Fm. appears suitable for long term CO2 storage, providing low risk of deterioration of producing gas fields (Troll). • Simulations of CO2 injection and migration predict limited lateral reaches of fluid migration, low pressure build-up and high potentials for residual and dissolution trapping, which is shown to be further enhanced by adjustment of well location and injection scheme. • A suite of scenario models illustrate the effect of site-typical geological heterogeneities such as non- and semi-permeable layers and directional permeability anisotropy. A workflow is presented for combining 3D seismic property data with a conceptual geological model, applicable for layered, sloping aquifer reservoirs. • Layered plume migration is likely in geological systems and relevant in evaluating trapping potentials and leakage paths. Implementation of discrete layers and zones with differentiated relative permeability curves according to porosity alternative or preferred migration paths. Abstract Geological sequestration is one proposed measure for greenhouse gas mitigation; and deep, saline aquifers are considered to hold large storage potentials for CO2. The Johansen Formation has been suggested by Norwegian authorities as a potential reservoir candidate due to its relative proximity to land and point sources for CO2. Reservoir evaluations must consider the given premise of zero interference with ongoing gas production in the Troll Field, providing geographical constraints. Recent data contributions; new 3D seismic data, attribute analyses, and revision of the depositional model form the basis of this modelling study. Porosity distributions were generated from quantified relations with acoustic impedance. The reservoir quality varies according to sedimentary facies, and differentiated relative permeability curves were assigned accordingly. Effects of directional anisotropy and site-typical geological heterogeneities were considered through scenario-modelling. The potential for dissolution and residual trapping of CO2 varies according to migration paths; and was estimated to 50–80% of injected CO2 after 150 years. Immobilisation was more efficient with increased sweep through reservoir zones with high irreducible gas fractions, and in scenarios where plume separation occurred. The main determinant, however, for improving trapping efficiency is the well location and injection scheme. Keywords CO2 storage, Fluid flow modelling, Reservoir characterisation, Reservoir modelling, Facies modelling, Parameterisation, North Sea, Sandstone, Geological heterogeneity, Trapping mechanisms, Attribute analysis, Saline aquifers -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/geoengineering. For more options, visit https://groups.google.com/d/optout.
