Laboratory of Thermodynamics and Energetics of Complex Fluids

• The Transport Properties group, person in charge : Guillaume GALLIERO, strengthened its expertise in the measurement of densities up to very high pressures (140 MPa et 130°C). The experimental results (density and viscosity) concerned mixtures of hydrocarbons and alcohol, refrigerant and lubricant, adipates and some stereoisomers. These measurements were systematically analysed through predictive models, some of which were developed in the laboratory. The group also possesses an original piezo-rheometer to study the viscoelastic properties of heavy oils. A major effort has also been made to develop dynamic molecular simulation so as to assess thermophysical properties, particularly in mixtures, in situations where it is difficult to conduct the experiment.

• The main research topics of the Colloïds and Interfaces group, managed by Christophe DICHARRY, deal with the experimental characterisation and modelling of liquid/liquid, gas/liquid and gas/liquid/liquid interfacial properties for bulk or confined systems in porous media. Oscillating pendant drop tensiometers, an ellipsometer, a Langmuir-Blodgett trough and an X-ray microtomograph are used to study these properties; some of these experiments can be carried out under pressure. Emulsion formation, stability and breaking issues as well as multiphasic flows in porous media are being studied. Concerning modelling, the gradient theory has been coupled with the SAFT-VR Mie theory so as to assess the interfacial properties of water/oil/gas systems in bulk or confined conditions. Monte-Carlo simulations of these properties in porous media are also being developed, and a third approach, the density fluid theory for inhomogeneous fluids, is currently under development.

  The study of gas hydrates is another important research topic developed by the team. Phase equilibria, inhibition and promotion, and capture of acidic gases by gas hydrate crystallisation are studied. High pressure laboratory pilots with adequate instrumentation and analysis capacities allow us to investigate gas hydrate issues up to 2900 psi.

• One of the key challenges of the Geomechanics group is the assessment of the tightness of storage facilities or the enhancement of the production capacities of non conventional reservoirs.  We aim at a proper understanding of the various mass transfer mechanisms of the fluid-solid interactions and of the mechanical response of the solid phase. Our research focuses on fluid flow in submicron- and micro-porous materials with evolving microstructure (with pores under 2nm and between 2 and 50 nm, respectively). We follow multidisciplinary and multi-scale approaches that encompass the physics and chemistry of surfaces and interfaces, poromechanics, acoustics, fluid mechanics and thermodynamics and associate theoretical models to experiments at different scales. We develop robust poromechanical failure models that combine nonlocal mechanics with a proper account of fluid confinement effects and/or phase changes and multicomponent saturation conditions. Significant progress can be achieved by combining molecular dynamics or Monte Carlo simulations and macroscopic density functional theories. Our aim is to relate such studies into comprehensive macroscopic models for more robust descriptions of complex and multicomponent systems.

CROSS-DISCIPLINARY THEMES

• The Heavy Oils theme, person in charge : Patrice CREUX, took an interest in macromolecules of asphaltene which are responsible for the high viscosity of oils. On these systems it has highlighted a surprising phenomenon of organic compound occlusion and a totally new rheologic behaviour of these particles. It also developed a microscopic approach to analyse the production of bubbles in conditions representing those of oil reservoirs. The numerical results obtained were confirmed by several experimental results obtained by different teams. Finally, it identified a key parameter for cold extra-heavy oil recovery.

• The cross-disciplinary theme Acid Gases led by Daniel BROSETA is related to CO2 capture and geological storage. In the field of CO2 capture, a promising method based on gas hydrates is being examined. In this method, CO2 capture is realized under large pressures, and it is therefore suited to the treatment of production gases when CO2 is to be reinjected in a geological formation. In the field of CO2 geological storage, the interfacial properties that control the sealing efficiency of the caprock, namely the brine/CO2 interfacial tension and the wettability of caprock minerals in presence of brine and CO2, are being investigated. A methodology to characterize the relevant caprock petrophysical properties has been devised and implemented on caprock samples from the ROUSSE depleted gas field, where the first CO2 storage pilot in France is taking place.