Switzerland’s CITru project is the country’s first attempt to test the feasibility of CO2 injection, via an existing exploration borehole at Trüllikon in northern Canton Zürich, targeting the Schinznach Formation (Upper Muschelkalk). A 2023 feasibility study (Diamond, Alt-Epping, Brett, Aschwanden, and Wanner; Report 2023-7, submitted to swisstopo, Rock Water Interaction group, University of Bern) assessed the reservoir properties at Trüllikon needed to determine whether injection was viable.
My contribution to this report was the discrete fracture network (DFN) analysis and the creation of permeability scenarios — computing reservoir permeability from a combination of rock-matrix properties, vertical drill hole fracture logs, a horizontal fracture log from a nearby borehole, and hydraulic test results. This multidisciplinary approach gave the project a more robust basis for evaluating exploration for both CO2 storage sites and geothermal energy in Switzerland, and reinforced how much subseismic-scale fracture and fault knowledge gaps can affect reservoir permeability — by orders of magnitude — motivating the subsequent FReMUK project.