An Analogue Approach to Characterize the Basement-Sediment Transition Zone as a Geothermal Reservoir
Abstract
The development of geothermal exploitation in the Upper Rhine Graben for heat and power generation requires detailed knowledge of the subsurface in order to mitigate associated geological risk and streamline exploitation techniques. In this area, several industrial projects have targeted the basement-sediment transition zone as a permeable reservoir. This is because the zone is located at a depth range where the temperature reaches values between 120 and 200 °C, which is economically exploitable for industrial heat or electricity. However, this zone is complex. Additionally, its geothermal potential is strongly affected by different types of heterogeneities, such as lithology, fracture networks and/or the geometry. Multidisciplinary and multiscale approaches are used on various sites (deep and shallow boreholes and quarries) to characterize the transition zone: structural analysis of the fracture network that constitutes the deep fluid pathway, geophysical investigations to image the geometry of this zone, fluid-rock interaction studies and petrophysical characterization to reconstruct paleo-fluid circulations and identify the most efficient fluid pathways. The various results are gathered into a conceptual model of the hydraulic behaviour of the transition zone for the sites and then used to develop new models to inform geothermal energy exploitation in this context.
Origin : Files produced by the author(s)
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