Probabilistic inference of fracture-scale flow paths and aperture distribution from hydrogeophysically-monitored tracer tests

JOURNAL OF HYDROLOGY

卷:567

Article

Shakas, A.¹  Linde, N.¹  Le Borgne, T.²  Bour, O.² 

[1] Univ Lausanne, Inst Earth Sci, Appl & Environm Geophys Grp, CH-1015 Lausanne, Switzerland

[2] Univ Rennes, Geosci Rennes, CNRS, UMR 6118, F-35000 Rennes, France

关键词: Fractured rock;    Hydrogeophysics;    Fracture aperture distribution;    Flow channeling;    Dispersion;   

DOI  :  10.1016/j.jhydrol.2018.10.004

来源: Elsevier

【 摘 要 】

Fracture-scale heterogeneity plays an important role in driving dispersion, mixing and heat transfer in fractured rocks. Current approaches to characterize fracture scale flow and transport processes largely rely on indirect information based on the interpretation of tracer tests. Geophysical techniques used in parallel with tracer tests can offer time-lapse images indicative of the migration of electrically-conductive tracers away from the injection location. In this study, we present a methodology to invert time-lapse ground penetrating radar reflection monitoring data acquired during a push-pull tracer test to infer fracture-scale transport patterns and aperture distribution. We do this by using a probabilistic inversion based on a Markov chain Monte Carlo algorithm. After demonstration on a synthetic dataset, we apply the new inversion method to field data. Our main findings are that the marginal distribution of local fracture apertures is well resolved and that the field site is characterized by strong flow channeling, which is consistent with interpretations of heat tracer tests in the same injection fracture.

【 授权许可】

Free