2.5-D discrete-dual-porosity model for simulating geoelectrical experiments in fractured rock

Victor Caballero Sanz (1) , Delphine Roubinet (2) , Serdar Demirel (1) , James Irving (1)

1 UNIL - Université de Lausanne = University of Lausanne
2 Géosciences Montpellier

Previous work has demonstrated that geoelectrical measurements, acquired either along the Earth’s surface or in boreholes, can be sensitive to the presence of fractures. However, a lack of numerical approaches that are well suited to modelling electric current flow in fractured media prevents us from systematically exploring the links between geoelectrical measurements and fractured rock properties. To address this issue, we present a highly computationally efficient methodology for the numerical simulation of geoelectrical data in 2.5-D in complex fractured domains. Our approach is based upon a discrete-dual-porosity formulation, whereby the fractures and rock matrix are treated separately and coupled through the exchange of electric current between them. We first validate our methodology against standard analytical and finite-element solutions. Subsequent use of the approach to simulate geoelectrical data for a variety of different fracture configurations demonstrates the sensitivity of these data to important parameters such as the fracture density, depth, and orientation.

Mots clés: Electrical properties; Fracture and flow; Electrical resistivity tomography (ERT); Fourier analysis; Numerical modelling; Numerical solutions

Domaines: Géophysique [physics.geo-ph]

Victor Caballero Sanz, Delphine Roubinet, Serdar Demirel, James Irving. 2.5-D discrete-dual-porosity model for simulating geoelectrical experiments in fractured rock. Geophysical Journal International, 2017, 209 (2), pp.1099-1110. ⟨10.1093/gji/ggx080⟩. ⟨hal-01622151⟩