Numerical Aspects of Using Vertical Equilibrium Models for Simulating CO2 Sequestration
Storage of CO2 in deep saline aquifers is considered an important means to reduce anthropogenic CO2 in the atmosphere. Assessing the risk of storage operations requires accurate modeling of migration of injected CO2. However, since potential injection sites typically are very large and time-scales long, flow simulation with traditional methods from the petroleum industry is often not feasible. Also, CO2 is very mobile and the flow is usually confined to thin layers, which put severe requirements on the vertical grid resolution. Using a vertical equilibrium assumption, the flow of a layer of CO2 can be approximated in terms of its thickness to obtain a 2D simulation model. Although this approach reduces the dimension of the model, important information of the heterogeneities in the underlying 3D medium is preserved. In this paper, we consider the Johansen formation, a candidate for CO2 sequestration, to compare the use of 3D simulations to simulations with a vertical equilibrium 2D model. We discuss numerical aspects of using the different methods, and demonstrate that the vertical equilibrium model provides more accurate results when the vertical grid resolution is low. Moreover, we investigate how averaging of parameters influences the accuracy of the vertically equilibrium solution.
- Ingeborg Ligaarden
- Halvor Møll Nilsen
- SINTEF Digital / Mathematics and Cybernetics
ECMOR XII - 12th European Conference on the Mathematics of Oil Recovery
06.09.2010 - 09.09.2010
European Association of Geoscientists and Engineers (EAGE)