3D thermo‐hydro‐mechanical simulation of the behaviour of a naturally fractured petrothermal reservoir in deep Upper Jurassic carbonates of the Bavarian Molasse Basin – Case study Geretsried

• Published in: Geomechanik und Tunnelbau 2022-02, Vol.15 (1), p.48-57
• Main Authors: Meneses Rioseco, Ernesto, Dussel, Michael, Moeck, Inga S.
• Format: Article
• Language: eng ; ger
• Subjects: 3D reservoir modelling; Carbonates; coupled thermoporoelastic effects; deep Upper Jurassic carbonates; Felsmechanik; Flow rates; Flow velocity; Fluid dynamics; Fluid flow; Fluid injection; Fractured reservoirs; fracture‐controlled petrothermal reservoir; Geologie; Geology; Geophysics; Geophysik; Heat transport; Hydrologie; Hydrology; induced thermal stresses; Injection; Intake temperature; Jurassic; Mechanical properties; numerical simulation; Reservoir performance; Reservoirs; Rock mechanics; Simulation; slip and dilation tendency analysis; Thermal stress; Three dimensional models
• ISSN: 1865-7362; 1865-7389
• DOI: 10.1002/geot.202100083

Based on multi‐scale and multi‐disciplinary measured data, gathered at the Geretsried geothermal site, a 3D reservoir model of the deep and fracture‐controlled Upper Jurassic carbonates in the North Alpine Foreland Basin is generated in this work. An efficient methodology is developed to numerically simulate the coupled reservoir processes of fluid flow, heat transport and thermoporoelastic stresses resulting from possible geothermal doublet operating schemes with cold fluid injection and production profiles in an enhanced naturally fractured reservoir. A variety of numerical experiments is conducted to study the reactivation potential and dilation tendency of the fracture and fault system. Simulation results show the spatiotemporal evolution of the thermoporoelastic stresses and the zone affected after 50 years of geothermal doublet operation. From these simulations, the thermoelastic response of a geothermal doublet operating with 60 °C fluid injection temperature and 20 l/s flow rate translates into a maximum induced thermal stress of around 49.4 MPa near the injection well. In terms of a long‐term reservoir performance and fault and fracture reactivation potential, the findings reveal a negligible risk to a sustainable geothermal doublet operation.