A novel surface-based approach to represent aquifer heterogeneity in
sedimentary formations
Abstract
Sedimentary formations that compose most aquifers are difficult to model
as a result of the nature of their deposition. Their formation generally
involves multiple processes (alluvial, glacial, lacustrine, etc.) that
contribute to the complex organization of these deposits. Representative
models can be obtained using process-based or rule-based methods.
However, such methods have several drawbacks: complicated
parametrization, large computing time, and challenging, if not
impossible, conditioning.
To address these problems, we propose a new hierarchical surface-based
algorithm, named EROSim. First, a predefined number of stochastic
surfaces are simulated in a given order (from older to younger). These
surfaces are simulated independently but interact with each other
through erosion rules. Each surface is either an erosive or a deposition
surface. The deposition surfaces represent the boundaries of
depositional events, whereas the erosive surfaces can remove parts of
the previously simulated deposits. Finally, these surfaces delimit
sedimentary regions that are filled with facies. The approach is quite
simple, general, flexible, and can be conditioned to borehole data. The
applicability of the method is illustrated using data from
fluvio-glacial sedimentary deposits observed in the Bümberg quarry in
Switzerland.