3D-Borehole Radar - A Routine Tool for The Detailed Imaging of Salt Structures

During the last decade, the 3D-borehole radar technique has demonstrated to be a valuable tool for the localization of the edges and for the investigation of the internal structure of salt domes. This methodology evolved to an integral component of the standard investigation program for new cavern development projects at many salt dome sites in Europe. A 3D-borehole radar probe, which runs within a vertical drill-hole through the salt formation, emits omni-directional radar signals. To map the 3D spatial coordinates of radar wave reflectors (geological interfaces) within the salt, the directions of the incoming radar signal reflections are determined apart from the distance of the probe to the reflector. A so called cross loop antenna as receiver unit in the probe allows for the recording of three separate signal shares. Together with the knowledge of the probe’s orientation the incoming angle of each signal can be clearly set and thus the coordinates of reflectors in the 3D space can be determined