The effect of hot water injection on sandstone permeability

• We address permeability change in sandstone due to heating from 20 °C to 70–200 °C.
• Literature analysis was combined with short-term permeability experiments.
• Physical and physico-chemical mechanisms were investigated.
• Permeability reduction occurred in sandstones containing the clay mineral kaolinite.

Seasonal energy storage can be achieved by hot water injection in geothermal sandstone aquifers. We present an analysis of literature data in combination with new short-term flow through permeability experiments in order to address physical and physico-chemical mechanisms that can alter permeability when sandstones are heated from 20 °C to 70–200 °C. The pore surface area per unit pore volume was used to normalise permeability data, so that the temperature effect on samples with different pore size could be compared. In sandstones containing the clay mineral kaolinite, heating reduced permeability, suggesting that the observed permeability reduction was due to kaolinite mobilisation. The effect was partly reversible.