Application of Cross-hole Seismic Tomography in Characterization of Heterogeneous Aquifers

Detailed characterization of subsurface geological heterogeneities which control fluid flow and transport is still an unresolved challenge in the geoscience community. While surface geophysical methods have helped in obtaining large scale parameter distributions, the decrease of resolution with depth limits their application for delineating heterogeneities at high resolution. This limitation has encouraged the use of cross-hole geophysical techniques such as cross-hole seismic tomography. Cross-hole seismic tomography which involves measuring travel times of seismic ray paths between two or more boreholes in order to derive an image of seismic velocities between the wells offers an approach for characterizing geological heterogeneities at a high resolution. Its application range from near surface aquifer studies, geothermal, to deep oil and gas reservoirs (Sainkov et al 2005; Tselentis et al 2011). Becht et al., (2007), evaluated the use of cross-hole seismic tomography for high resolution aquifer characterization. In this study, we present a case application of cross-hole seismic tomography for a high resolution characterization of the Prakla-Seismos field test site. Detailed velocity distributions are correlated with available borehole geological data to better delineate subsurface heterogeneity which provide useful information for an improved groundwater flow and contaminant transport modeling in the area.