PhD 6: Active Fiber-Optic DTS methods to monitor subsurface flow dynamics

Objectives: Combining active and passive DTS methods for quantifying flow distribution in i) borehole applications under periodic and interference hydraulic tests and ii) in-situ buried cable in heterogeneous sandy aquifers, saline wedges and hyporheic zones.

Expected Results: Fiber Optic Distributed Temperature Sensing (FO-DTS) is an innovative tool that allows continuous temperature monitoring with an excellent spatial resolution. Recent applications demonstrate the utility of passive FO-DTS for characterizing flows and monitoring thermal tracer tests in heterogeneous media. Passive methods are however often limited to qualitative information about flow distribution. Active methods, which consists in using heated cables or local thermal sources showed very promising results to quantify distributed flow velocities. The first objective of the ESR will be to adapt these recent developments in various hydraulic conditions (cross-borehole interference tests, periodic hydraulic tests and ambient conditions) to develop an innovative hydraulic tomography approach in fractured media (Ploemeur and Äspö sites) based on distributed data on flows and temperature changes. The second objective of the ESR will be to develop similar active DTS methods in buried cables within saturated porous media in order to quantify in-situ fluxes within sandy aquifers (Hermalle site), saline wedges (Argentona site) and/or within the hyporheic zones (River Selke site). The obtained data and the results of inversion will be compared and combined with data and/or inversion scheme developed by ESR 2, 3, 4, 7, 11 and 14

Supervisors: CNRS Rennes/ Co-Supervisors: CSIC Barcelona, OSU Oregon, SILIXA
Contact: Olivier Bour olivier.bour(at)univ-rennes1.fr

To apply : use our Recruitment Form !