Review on chemical stimulation techniques in oil industry and applications to geothermal systems

The Enhanced Geothermal Systems (EGS) are dedicated to the exploitation of the heat present in deep hot rocks of limited permeability. But this extraction is only feasible if the reservoir permeability is sufficient to ensure a fluid circulation between injection and production wells. Economic exploitation of enhanced geothermal systems is dependant on natural or induced mineral precipitation and associated decrease in permeability of the system. This may inhibit fluid flow in well casings or in rock fractures and
therefore decrease the heat extraction from the system. One solution to this problem consists in injecting a reacting fluid into the wells, in order to dissolve the secondary minerals scaled on the casing or partially sealing the fractures, to increase the permeability and hence to develop the reservoir.