The Integrated GeoModeling Analysis System (GeoSIAM) has previously been used by RSE for the simulation of CO₂ production and storage processes, for addressing a wide range of geothermal site analyses, including those with a strong presence of CO₂ in gaseous form, and for solving issues related to the production and storage of natural gas in geological reservoirs. In recent years, a module has been added to interface with a finite element geomechanics code to study the effect of fluid dynamics, analyzed with GeoSIAM, on the geological formations within the examined domain.

Recently, the need arose to simulate the management of depleted methane reservoirs used as geological storage for hydrogen. This required a complete overhaul of the MethodRdS pre- and post-processing module and the 3D fluid dynamics simulator Tough2RdS, with the inclusion of new modules and state equations capable of treating hydrogen as an additional component. Another adjustment factor was the simultaneous integration of the 3D spatial heterogeneity model developed by RSE with version 4.0.1. The updated modules, in version 4.0.2, have been included in GeoSIAM version 2.1. As a result of this restructuring, it became necessary to update the user manuals for the modules and GeoSIAM.

The user manual was therefore updated and integrated, with particular attention given to the innovative aspects not yet documented, especially those related to the restructured modules. These updates were integrated with the essential operational instructions for the unchanged modules, to provide the system’s end user with a practical, easily consultable, and self-contained manual. The manual described in this document, which also includes the necessary instructions for installing the system and preparing the input data, serves as a tool to accelerate all phases of analysis, reduce the likelihood of errors, and functions as an indispensable guide for users using GeoSIAM for the first time in its current version 2.1.