Next we apply the multi-phase fluid flow simulations of Lengler et al. (2010) to account for the lateral variability in the petrophysical properties of the storage formation at Ketzin. Lengler et al. (2010) performed simulations on multiple realizations of the Ketzin reservoir using a stochastic Monte Carlo approach in order to take into account the high degree of uncertainty in the reservoir characterization at the scale required for fluid flow simulations. In this paper, we use a similar approach, but this time to investigate the impact of the reservoir temperature on the fluid migration and, in turn, on the 4D seismic data. Hydrogeological studies at the Ketzin site (Norden et al., 2010) have shown that a 2D radially symmetric model of the upper part (33 m) of the Stuttgart Formation can be used to interpret the 3D data acquired near the injection well (Fig. 7). This model accounts for the presence of channel sandstones in the reservoir that are the most favorable for CO2 migration and contains effective porosities in the range of 20–25% (Förster et al., 2010). As known from core and log analysis of the injection well Ktzi201/2007 and the first observation well Ktzi200/2007, the reservoir is composed of two high porosity sandstone layers. These layers are separated by a thin strongly cemented sandstone layer (Norden et al., 2010). Since the thickness of this layer is in the decimeter range, it cannot be detected with the seismic wavelengths typically available from surface-seismic measurements. However, this layer is known to be a significant constraint to fluid migration due to its low permeability (Wiese et al., 2010).
upper part
33 m
m
channel sandstones
effective porosities
20–25%
%
high porosity sandstone layers
two