Speaker: Ever-Dennys Coarita-Tintaya
Date: Thursday 28th of October 2021, 1:15 pm.
Abstract:
Context of this work is related to underground hydrogen storage in salt caverns. The operational phase (injecting and extracting, according to daily or seasonal cycles) can affect stability of the cavern and initiate development of fractured zones. This can modify the transport properties and therefore potentially cause hydrogen leakage problems around the cavern.
Based on the mechanical and hydromechanical behaviour of salt rock known from experimental data, as well as on the rheological models available for this material, we propose a model that considers the short-term and long-term behaviour of salt rock. In the short-term behaviour we have a macroscopic elastoplastic and damage constitutive model. In the long-term behaviour, the three creep types are considered: (i) transient (or primary) creep; (ii) steady-state (or stationary) creep; and (iii) acceleration (or tertiary) creep. Thus, this model describes the key mechanisms of salt rock behaviour.
To evaluate and validate the numerical implementation in Comsol Multiphysics®, triaxial tests were simulated and the results obtained correlate well with the theoretical criteria. The application of the proposed model was evaluated on salt caverns where hydromechanical simulations were carried out under saturated conditions. The analysed scenarios were shallow and very depth caverns, as well as seasonal and daily hydrogen operating cycles.