Work

Scenario-based sensitivity analysis of petrophysical parameter influence on geomechanical stability during CO2-based thermo-mechanical subsurface energy storage

Year: 2026

Type: article

Abstract: Decarbonising the energy system requires dependable energy storage solutions to buffer the intermittent production of renewable electricity. Geological energy storage offers significant potential, but safe operations depend on a robust understanding of the geomechanical system behaviour. This study ranks the impact of petrophysical reservoir parameters on the geomechanical performance of a gas-based thermo-mechanical energy storage approach, exemplarily for a supercharged hybrid gas-based energy storage (SH-GES). For this a three-dimensional thermo-hydro-mechanically coupled numerical parameter study was carried out, modelling 1.5 years of CO2 cushion gas injection followed by 5 years of cyclic injection and production of CO2. A total of 270 parameter combinations were evaluated by varying permeability, Young’s modulus, Poisson’s ratio, thermal expansion coefficient, and Biot coefficient of the reservoir. Geomechanical integrity was assessed using Mohr-Coulomb-based safety factors for the reservoir, bounding formations, and a fault, as well as minimum effective principal stress to identify possible tensile failure. A machine learning-based sensitivity analysis employing SHAP-values was used to rank parameter influence. The results show that transient thermoelastic stress redistributions dominate the geomechanical response. Young’s modulus and thermal expansion coefficient are identified as the primary controls on shear and tensile stability, affecting both reservoir and bounding formations. Early stages of CO2 cushion gas injection represent the most critical operational phase. Fault stability remains uncompromised for the investigated scenarios. These findings emphasise the need for thorough petrophysical characterisation and time-dependent coupled numerical studies in the geomechanical assessment and design of gas-based subsurface energy storage systems.

Source: Geomechanics for Energy and the Environment

DOI: 10.1016/j.gete.2026.100870

Authors: Daniel Bücken, Tobias Backers, Thomas Heinze

Institution: Ruhr University Bochum

Language: English

Topic: CO2 Sequestration and Geologic Interactions

Subfield: Environmental Engineering

Field: Environmental Science

Domain: Physical Sciences

SDGs: Climate action, Affordable and clean energy

Open Access status: hybrid

Estimated APC paid: $3,050