Geostatistical characterization of a complex semi-permeable layer

Presents a study to quantify the lithofacies distribution of a complex semi-permeable layer consisting of fluvial and organic deposits. In a small study area in the central Rhine-Meuse delta a large number of drillings were made in a semi-permeable layer overlying shallow permeable aquifers. Detailed cross sections and semivariogram analysis are used to quantify the spatial variability of fluvial overbank deposits in the semi-permeable layer and to determine minimal drilling distances for detailed mapping of the lithofacies. Conditional indicator simulation is applied to obtain simulated stochastic images of the semi-permeable layer. These images may serve as analogues for similar layers found at greater depths. -Authors