Scaling in fractured geothermal carbonate reservoir rocks: An experimental approach

•Experimentally induced dissolution and precipitation processes in fractured carbonates document changes relevant to geothermal subsurface reservoirs and storage approaches.•Inducing new pathways affects fluid migration through a geothermal rock reservoir in a manner that differs from natural fluid pathways.•Hydrothermal fluid-rock interaction related to temperature and pressure changes enhances dissolution-reprecipitation rates, increasing scaling risk.•Optical and (isotope) geochemical tools quantify the dissolution and precipitation processes and offer tools for monitoring programmes. Mineral precipitates along thermal fluid pathways (scaling) and clogging by unconsolidated grains inversely affect the efficiency of geothermal systems. An experimental approach is presented to quantify dissolution-precipitation processes in fractured, geologically complex carbonate rocks of Devonian age. The outcome suggests that the dissolution-precipitation processes must be placed in the context of different fluid properties and pressure conditions between the injection and the production well. A geochemical monitoring program documenting the processes in the carbonate aquifer rocks is presented. Experimental work must be combined with field and modelling approaches to unfold its full strength.