As part of the development of the large-scale hydrogen supply chain, the role of underground hydrogen storage is gaining ever more importance and represents a technological challenge at an international level – and can still be considered a little-researched topic.
The activities’ goal is to carry out a preliminary assessment of the suitability of the caprock-reservoir systems on Italian territory for the geological storage of hydrogen. In detail, an in-depth geological study is carried out on the real conditions (in terms of temperatures, pressures, and lithology) of the systems investigated for the safety of hydrogen storage activities as far as corrosion phenomena and leakage from the storage facilities triggered by chemical and biochemical reactions are concerned.
The activities carried out were divided into different phases, which include:
1. Bibliographic research on the conditions that favor or inhibit corrosion reactions in geological reservoirs;
2. Following the results of the bibliographic analysis, definition of the “sensitive” parameters to be used for the database analysis and of “risk classes”;
3. Development of the investigation methodology, analysis of the data in the databases already available in RSE relating to geothermal wells and wells built for the exploration and production of hydrocarbons, and summary of the first results obtained from the analysis of the geothermal wells database;
4. Development of a laboratory activity based on the real process simulation and aimed at carrying out hydrogen injection tests (pure or in a H2NG mixture) on lithologically different rock samples to evaluate (at laboratory scale) the stability of the system caprock-reservoir at the temperature and pressure conditions defined as suitable according to the previous research phases.
In brief, the work carried out represents a preliminary and preparatory approach to the development of a real “Hydrogen Laboratory” while performing the activities; based on experimental laboratory tests and possible pilot studies, said laboratory should lead to testing the technical feasibility of underground hydrogen storage by analyzing the conditions of geological reservoirs, chemical and biochemical reactions, and the behavior of materials (e.g., cements and well packers).