Single-hole GPR reflection imaging of solute transport in a granitic aquifer

Abstract

Identifying transport pathways in fractured rock is extremely challenging as flow is often organized in a few fractures that occupy a very small portion of the rock volume. We demonstrate that saline tracer experiments combined with single-hole ground penetrating radar (GPR) reflection imaging can be used to monitor saline tracer movement within mm-aperture fractures. A dipole tracer test was performed in a granitic aquifer by injecting a saline solution in a known fracture, while repeatedly acquiring single-hole GPR sections in the pumping borehole located 6 m away. The final depth-migrated difference sections make it possible to identify consistent temporal changes over a 30 m depth interval at locations corresponding to fractures previously imaged in GPR sections acquired under natural flow and tracer-free conditions. The experiment allows determining the dominant flow paths of the injected tracer and the velocity (0.4-0.7 m/min) of the tracer front.

References in corpus (1)

• Fracture imaging within a granitic rock aquifer using multiple-offset single-hole and cross-hole GPR reflection data

Cited by in corpus (4)

• Inferring transport characteristics in a fractured rock aquifer by combining single-hole GPR reflection monitoring and tracer test data
• Conditioning of stochastic 3-D fracture networks to hydrological and geophysical data
• Hydrogeophysical characterization of transport processes in fractured rock by combining push-pull tracer tests and single-hole ground penetrating radar
• Effective modeling of ground penetrating radar in fractured media using analytic solutions for propagation, thin-bed interaction and dipolar scattering