Skills to efficiently and safely approach the design, the operations and the monitoring of underground storage systems: - Knowledge of the specificities of different underground storage types. - Good understanding of the phenomena and mechanisms taking place when injecting natural gas, CO2, or hydrogen underground. - Quantitative evaluation of storage/sequestration capacity under simplified assumptions. - Awareness of the requisites of storage sites to contain fluids. - Quantitative evaluation of main aspects concerning the safety of storage systems. - A critical approach to review real data for site assessment and monitoring. Understanding of the technical and safety challenges affecting the process plants used for underground fluid injection and withdrawal. Communication skills, ability to use and understand the technical language and terminology adopted worldwide in the industries. Ability in increasing knowledge by selecting the appropriate technical and scientific literature.

Students should have the background provided by the following courses: Fluid Mechanics in Porous Media; Reservoir Engineering; Reservoir Geomechanics; Fundamentals of process plants and Thermodynamics.

The course consists in two main moduli: 1) Design, operations and monitoring of underground storage systems modulus: - Purposes of the storage activity for CH4, H2 and CO2 - Thermodynamic behavior of CH4, and H2 and CO2 - Characterization of depleted reservoirs, deep saline aquifers and salt caverns from the geological and fluid-flow perspectives. Necessary laboratory and field data. - Interaction between hosting formations, their saturated fluids, and the injected gases - Storage capacity - CO2 trapping mechanisms - Monitoring and safety assessment of underground and sequestration storage systems - Numerical simulation of fluid-flow system (black oil and compositional approaches) for storage and sequestration activities - Practical exercises 2) Process plants for underground fluid injection and withdrawal: - Process plants; operational and safety issues - Main safety issues of storage systems and monitoring techniques - Practical exercises

The main part of the course aims at addressing the scientific, technical, and operational aspects of underground fluid storage (51 hours). A complementary part provides the fundamentals of the process plants needed to manage injection into and production from deep geological formations, including operational and safety issues, applied to fluid storage (9 hours). Around 70% of the total hours are dedicated to lecture, 30% to exercises. Exercises are meant for the students to approach practical problems by applying the theory and methods discussed during the lectures: 1) Equations of State 2) storage capacity for depleted reservoirs and aquifers, 3) investigation of the sealing efficiency of cap rock formation, 4) induced ground movements, 5) plan of storage and sequestration strategies. Only for some exercises specified by professors and introduced during class, students are required to prepare a booklet containing the solutions. The booklet must comply with the following requirements: • Written in Word; • Equations must be written using the Math Editor; • Plots must be created in MATLAB or Excel; • Plots must be pasted as images; • File name format: “FamilyName_StudentID.docx” or “FamilyName_StudentID.pdf”; • The file must be uploaded to the “Elaborati” page of the course; • Upload deadline: one week before the final examination. For the process plants, two study cases about the re-use of the topside infrastructures and depleted reservoirs are developed. The first study case proposes the injection and production of a CH4–H2 mixture for temporary underground storage in a depleted reservoir to meet strategic energy supply. The second study case addresses the storage of the CO2 captured from the atmosphere in a depleted reservoir to reduce the atmospheric concentration of greenhouse gases from anthropogenic emissions. A focus on CO2-related safety issues completes the last study case.

Reports from international agencies and organizations. Scientific papers.

Lecture slides;

Exam: Written test;

The ability to critically examine a technical problem, also by integrating knowledge gained in other courses and contexts if needed, to select the appropriate models and methods and to correctly calculate the solution is expected. The exam is related to theoretical and applicative aspects and comprises true/false options, multiple choice questions, open questions, and mostly problem-solving. The exam is closed notes and closed books. Each answer will be assigned marks depending on the complexity of the question. The score is attributed by taking into account the correctness and completeness of the answers to the questions, the ability to elaborate the topics presented and discussed in class for problem-solving; the ability to support the discussion with a correct nomenclature and clear form and with graphs (when relevant/required).

In addition to the message sent by the online system, students with disabilities or Specific Learning Disorders (SLD) are invited to directly inform the professor in charge of the course about the special arrangements for the exam that have been agreed with the Special Needs Unit. The professor has to be informed at least one week before the beginning of the examination session in order to provide students with the most suitable arrangements for each specific type of exam.