High-resolution 2D landstreamer vibroseis applied in groundwater mapping of miocene deposits

The Miocene succession in central and southern Jylland was formed during four phases of shoreline progradation into the basin that covers present-day Denmark. The deposits comprise several aquifers with potential drinking water resources and have been investigated by drilling and acquisition of seismic data integrated with sedimentology and biostratigraphy. The multi-disciplinary approach and an exclusively large dataset of 1200 km high-resolution 2D onshore seismic data and 150 boreholes, 100-400 m deep, has formed the basis for an extensive mapping of the Miocene succession. One of the cornerstones has been the generally very high data quality of the seismic data acquired in the past 10 years using the landstreamer vibroseis method. A detailed interpretation of the seismic data has been performed, focussing on mapping the extent of sand-rich bodies, by identifying top and base of separate delta lobes and fluvial deposits. The result of the investigations is a dynamic 3D geological model that reflects the basin development and the depositional processes as well as the palaeogeographical development during the Miocene. The model is intended to serve as a geological database of lithological and stratigraphical information and provides a better understanding of the geological architecture of the aquifers than traditional lithofacies models.