PhD 9 : Geophysical signatures of spreading and mixing

Objectives: Upscale transport processes to scales resolved by geophysics and test spreading and mixing theories

Expected Results: Geophysical time-lapse inversions provide upscaled estimates of temporal changes in bulk properties that may provide constraints on dispersion (spreading), but they have never been used to-date to infer statistics of mixing, which controls (fast) chemical reactions. We suggest that simultaneous acquisition of geophysical data and concentration fields by means of millifluidic experiments will enable novel and fundamental insights that will ultimately influence hydrogeophysical research at the field scale. Millifluidic experiments in artificial media of varying complexity (developed by ESR 12) will provide high-resolution images of the concentration field during tracer experiments. Simultaneous acquisitions of geophysical data (representing effective upscaled properties at the scale of the sample) in the form of electrical resistance and self-potential (i.e., the electro-diffusive contribution) will be influenced by pore scale and meso scale heterogeneities of the salinity and liquid phase. These combined data sets will be used to develop new theory and experimentally demonstrate how spreading and mixing of solutes in heterogeneous porous media, manifest themselves in geophysical data. These findings can then be used to make inferences about the statistics (not the actual salinity distribution) of spreading and mixing in porous media.

Supervisors: UNIL Lausanne / Co-Supervisors: CNRS Rennes, CSIC Barcelona
Contact : Niklas Linde Niklas.Linde(at)unil.ch

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