At ETH Zürich, we successfully completed a core-scale laboratory experiment that studied the chemical reactivity of CO2-rich mixtures towards rock formations in Switzerland that could potentially be used for CO2 geological sequestration and/or CO2-based geothermal energy extraction. For this, we exposed two rock specimens from the Muschelkalk and the Gipskeuper formations (one reservoir rock and one caprock) to water-saturated CO2 under elevated pressure and temperature conditions for several weeks. Before starting the experiment and upon completion, a wide range of high-resolution techniques, such as scanning electron microscopy, x-ray computed tomography, x-ray diffraction, among others, were employed to characterize the evolution of the morphology, petrophysical properties, and chemical composition of the samples. This experimental investigation represents a critical step toward establishing the long-term security and technical feasibility of deploying CCS and CO2-based geothermal energy systems.

Additionally, during Nicolas’ secondment at RWTH Aachen, we have been working on the deterministic and stochastic modeling of various types of deep geothermal systems. Several reservoir models (e.g., open-loop vs. closed-loop configurations & water-based vs. CO2-based extraction) have been constructed in order to establish their comparative techno-economic performance for heat and electrical power generation. For our reservoir modeling, we have used stochastic methods and Machine Learning tools that allowed us to efficiently consider a wide range of reservoir properties and operating conditions. This modeling study aims to answer the question: What is the most cost-effective strategy to develop geothermal energy pervasively using today’s reservoir engineering and drilling technology?