Starting from the ‘50s, underground storage of nuclear wastes, hydrocarbons, as well as CO2 sequestration, are becoming more and more widespread techniques for managing the growing energy demand in industrialized countries and mitigating the related environmental impact. Currently, these techniques are strategic, on one hand to improve the efficiency of the consumption of mineral and energy resources toward a sustainable use of fossil fuels, on the other to ensure the disposal of high activity radioactive wastes to be as safe as possible. The role of underground repositories of gas is of main relevance for industrial countries in order to obtain significant economic savings, supplying these resources during spring-summer time and withdrawing the unavailable volumes during fall-winter. Conversely, underground storage of hazardous wastes is fundamental for environmental rather than economic issues. Finally, storage of carbon dioxide is a useful tool to help reduce the environmental impact of fossil fuels and prepare the transition to system based on renewable energies.
The most significant issues concerning natural or artificial repositories are, on one hand, macro- scale effects, e.g. surface displacements (uplift or subsidence), sinkholes or fault activation, on the other, leakages or transport of the stored materials through conducting rocks, i.e. assessment of the tightness of the storage facilities. The first class of problems is related to field-scale effects, the second one to micro/nano-scale effects. The role of poromechanics in the design, management and abandonment of underground repositories for addressing the issues above has been progressively recognized to be more and more relevant.
The aim of this mini-symposium is to present an up-to-date overview of the state of the art in the understanding and modeling of processes related to the storage of fluids underground, and emphasize the most recent advances in the field. Moreover, this mini-symposium can help create links between investigators operating in adjacent fields, such as theoretical modeling, lab and in-situ experimentation, and numerical implementation, sharing the most significant results. The covered topics include, but are not limited to: