Simulation Numérique D'écoulements Diphasiques Compositionnels Thermiques en Milieux Poreux Et Ses Applications À la Géothermie Haute Énergie

Download or read book Simulation Numérique D'écoulements Diphasiques Compositionnels Thermiques en Milieux Poreux Et Ses Applications À la Géothermie Haute Énergie written by Laurence Beaude and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The study of the subsurface flows is important for various applications such as energy or nuclear waste storage. This thesis, performed in collaboration with the French Geological Survey (BRGM), is dedicated to the simulation of non-isothermal compositional two-phase flows in porous media and its applications to high-energy geothermal fields and more precisely to the Bouillante field (Guadeloupe, French West Indies). First of all, two persistent variable formulations are compared in terms of implementation and numerical convergence. In these two formulations, the choice of the principal variables is based on with the extension of the phase molar fractions by the one at thermodynamic equilibrium with the present phase. It results that the set of principal variables and equations does not depend on the set of present phases. It also has the advantage to express the thermodynamic equilibrium as complementarity constraints, which allows the use of semi-smooth Newton methods to solve the non-linear systems. Moreover, this thesis presents a new methodology to combine a node-centered discretization (the Vertex Approximate Gradient scheme - VAG) and a face-centered discretization (the Hybrid Finite Volume scheme - HFV) on arbitrary subsets of cells or faces in order to choose the best-suited scheme in different parts of the mesh. Indeed, hybrid meshes composed of different types of cells are best suited to discretize the geology and geometry of the different parts of the geothermal system. Then, the scheme is adapted locally to the type of mesh/ cells and to petrophysical properties. The convergence analysis is performed in the gradient discretization framework over second order diffusion problems and the convergence is checked numerically on various types of hybrid three-dimensional meshes. Then, the VAG-HFV discretization is extended to non-isothermal compositional liquid-gas Darcy flows and is applied on the two dimensional cross-section of the Bouillante high temperature geothermal reservoir. Another important aspect of the geothermal flows modelling consists in considering the interactions between the porous medium and the atmosphere. Since the coupling between the porous medium and the 2D surface of 3D atmospheric flows is not computationally realistic at the space and time scales of a geothermal flow, the soil-atmosphere interaction is modelled using an advanced boundary condition accounting for the matter (mole) and energy balance at the interface. The model considers an atmospheric boundary layer with convective molar and energy transfers (assuming the vaporization of the liquid phase in the atmosphere), a liquid outflow condition at seepage surfaces, as well as the heat radiation and the precipitation influx. This boundary condition is assessed using a reference solution coupling the Darcy flow to a full-dimensional gas free flow. Then, it is studied numerically in terms of solution and convergence of the Newton-min non-linear solvers on several geothermal test cases including two-dimensional simulations of the Bouillante geothermal field. In addition is presented the collaborative project which took place during the CEMRACS summer school 2016. The project consisted in adding a multibranch thermal well model into the ComPASS code, a new geothermal simulator based on unstructured meshes and adapted to parallel distributed architectures with the ability to represent fractures.