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Reference : UMR7327-MARROU0-004
Workplace : ORLEANS
Date of publication : Wednesday, January 08, 2020
Type of Contract : FTC Scientist
Contract Period : 24 months
Expected date of employment : 1 April 2020
Proportion of work : Full time
Remuneration : Gross salary 2617-3017 €/month
Desired level of education : PhD
Experience required : 1 to 4 years
The ISTO laboratory, as part of its commitment to scientific research projects accelerating the energy transition, has developed with its industrial partners (Adionics, Electricity of Strasbourg Geothermal, Fonroche) and the BRGM an ambitious project (Therma'Li) of valorization of the geothermal brines of the Rhénan graben. The ISTO's scientific contribution is to study the key stages of dissolution reactions - precipitation of minerals at different temperatures (25 - 160°C) and pressures (5 - 20 bar). The geothermal brine (100 g/l) contains attractive lithium concentrations (155 - 200 mg/l). The scientific challenge is the mechanistic understanding of the thermokinetic processes involved in the dissolution – precipitation of minerals in the surface geothermal exchangers and the near well bore of the re-injection of the valorized brine (extraction of heat and lithium).
The mission of the research associate comes in two major tasks. First, he / she will design and perform laboratory experiments (batch type closed systems) and interpret the results from numerical models in order to deduce the reaction mechanisms at the origin of the mineral deposits. This first stage of the project focuses on the cooling-heating steps (simulating different steps of the geothermal loop) of the brine from its initial temperature (200°C) to its return to the geothermal reservoir at low temperature (80°C). A precise thermodynamic diagnosis of the geothermal fluids aiming identifying the family of precipitating minerals (i.e., carbonates, sulphates, sulphides, silica, etc.) will be made. The laboratory experiments, in closed systems, will use geothermal brine samples and will be achieved at temperatures between 25 and 160°C. Fluid analyzes and fine characterizations of precipitated solids are the input for thermodynamic and kinetic modeling. In a second step, reactive column experiments (open systems) will be carried out simulating the behavior of the cooled/valorized fluids pathways when it is reinjected into the reservoir. The reinjected brine is strongly out of thermal and chemical equilibria. This will generate abrupt fronts in the reservoir: i) moving thermal fronts associated to the cold bubble in the geothermal field; ii) reactive fronts due to the thermodynamic imbalance introduced by cooling, partial extraction of certain salts, etc. The impact of these moving fronts on the injection index must be evaluated. Flowing through experimental columns of cooled fluid using reservoir cores (plugs or reconstituted cores from drilling debris) will be performed. An analysis before / after experiments will highlights the consequences of the dissolution-precipitation reactions of minerals in the porosity and / or the fractures network. These results will provide key observable data for reactive transport numerical simulations.
- Skills for measuring physical, chemical, hydrothermal and multiphase hydrogeochemical systems (with different interacting phases: rock - water that can be highly salty - complex gases) at high temperature - high pressure
- Knowledge of laboratory techniques for the conceptualization of innovative experiments for tackling scientific locks upstream of technological and industrial locks
- Strength knowledge on thermodynamic approaches and kinetic mechanisms of mineral dissolution-precipitation reactions with a strong scientific curiosity to deepen the theoretical analysis of the acquired results and identifying the key mechanisms for interpretation the experimental observables
- Strong curiosity to interact with specialists of related fields (or interfaces) and industrialists to be able to work in a transverse team
- Hydrogeological and hydrogeochemical field knowledge will be appreciated
- Ease of writing scientific articles for publication of the scientific results
- English language: B1 to B2
The researche associate, joining the Therma'Li project team from the ISTO researchers and engineers, will exchange regularly with the other project partners (including BRGM and Adionics). He/she has in charge the development and implementation of the experimental approach to the study of coupled thermokinetic and reactive transport phenomena and the interpretation of the results and their scientific valorization by scientific publications and presentations in specialized international conferences.
Constraints and risks
Reactive geochemistry, numerical modeling and couplings (THMC) in predictive geosciences, fluid mechanics, hydrogeology, solid physics and physic-chemistry of hydrogeological systems.
Beginning of the contract: 3rd quarter 2019 (postdoc for 2 years). This position is open till July 15.
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