Mapping Hydraulically Permeable Fractures Using Directional Borehole Radar and Hole-to-Hole Tomography With a Saline Tracer

摘要

Reflection-mode borehole radar and transmission-mode radar tomograms image heterogeneity in the electromagnetic properties of rock. Heterogeneity may be produced by interfaces between different rock types, foliation, and fracturing. In crystalline rock, hydraulic flow is primarily through fracture networks rather than through the rock matrix. Borehole radar methods have been applied to help map flow paths in crystalline rock. Correlation of features identified in borehole radar reflection records and tomograms with hydraulic flow paths is generally uncertain because the records show responses to heterogeneity of all kinds, not just to hydraulically permeable features.