MAPPING PERMEABILITY IN HETEROGENEOUS AQUIFERS USING HYDROLOGIC AND SEISMIC DATA

A new method is presented for identification of the permeability distribution in near-surface aquifers. In addition to using the usual sparsely sampled pressure and permeability data, the method incorporates densely sampled seismic data, as obtained from a reflection or tomography survey, along with empirical relationships between seismic and hydraulic properties. The procedure is to first estimate by hydrologic inversion a pressure field. Then the velocity-permeability-pressure relationship is used to map the inverted pressure and measured seismic data to multivalued estimates of the permeability. Of those, the most probable value, based on the hydrologic inversion, is selected. In synthetic case studies the tremendous increase in coverage offered by the seismic data leads to dramatically better results in terms of both accuracy and resolution. An appealing feature is the use of relatively easy to acquire pressure data; a second is the incorporation of geophysical data which can sample an entire aquifer remotely without the need for an expensive and invasive drilling program.