Numerical formulation for a simulator (CODE_BRIGHT) for the coupled analysis of saline media

Abstract

IntroductionSalt rocks are being considered as potential recipients for geologic disposal of nuclear waste because of their favourable hydraulic and mechanical properties. In essence, processes controlling the behaviour of salt rocks are similar to those occurring in other media, except that they take place at unusually fast rates. The high solubility of salt in water is one of the causes of these high rates. In fact, creep deformation of wet salts takes place much faster than under dry conditions. This can be explained by means of a mechanism of creep deformation based on salt dissolution, molecular diffusion and precipitation at the pore scale caused by stress concentration [1,2].The high hygroscopic character of salt facilitates condensation of water in the mineral surface which in turn causes dissolution. These phase change processes are associated with release or uptake of energy. Another phenomenon that can occur in saline materials is the migration of brine inclusions through the crystalline structure [3,4]. These inclusions may disappear in grain boundaries or come into existence in contacts where brine films are entrapped. Therefore, porosity may undergo changes caused not only by deformation but also due to dissolution/precipitation or, perhaps with a lesser influence, by brine inclusions production/annihilation.The complex behaviour of saline media requires new theoretical and numerical developments. The study of the basic mechanisms has revealed that coupling between thermal, hydraulic and mechanical problems may be required in some cases. We have developed[5] the governing equations for nonisothermal multiphase flow of brine and gas in deformable saline media. These include mass balance equations for the species in the system (salt, water and

Two-phase flow effects on the CO2injection pressure evolution and implications for the caprock geomechanical stability

“…Thus, the outer boundary condition does not influence the results and the storage formation in our model is an infinitely acting aquifer. We simulate CO 2 injection in a deep saline formation using the finite element code CODE_BRIGHT [33,34], extended for CO 2 injection [25]. CO 2 density is calculated using the cubic Redlich-Kwong equation of state with the parameters proposed for CO 2 by Spycher et al [6].…”

Probabilistic Analysis of a Rock Salt Cavern with Application to Energy Storage Systems

“…During last four decades, tens of different constitutive models are introduced to simulate the thermo-mechanical behaviour of rock salt through mathematical equations. Among the others, one may mention studies of Hansen & Carter (1983); Olivella et al (1996); Hou (2003) Cristescu & Hunsche (1998)). In the following, three well established constitutive models in both industrial and research communities are presented and subsequently applied to study the response of the cavity.…”

“…However, as the main focus of this thesis is proposing a probabilistic approach to face with such complex application dealing with a significant amount of uncertainties, and in the sake of simplicity, the thermal interactions are neglected and the numerical simulation is done at constant ambient temperature T=298 K. GID software models the salt cavern with the above mentioned simplified geometry. GID is used as the pre-processor and post-processor of the Code-Bright finite element solver (Olivella et al, 1996).…”

Simulation aided testing of hydro-mechanical processes on clay

“…A series of numerical computations have been performed to simulate the equalisation curve presented in Figure 3 using the fully coupled thermo-hydro-mechanical finite element code CODE_BRIGHT [1]. The main challenge of the simulation is to compute numerically the important changes in axial strain and its evolution with time and verify if suction stabilises at the elapsed time used in the experimental procedure.…”