Chemical Impact of Elevated CO2 on Geothermal Energy Production

Abstract

Numerical simulations have shown that the use of supercritical CO2 instead of water as a heat transfer fluid yields significantly greater heat extraction rates for geothermal energy. If this technology is implemented successfully, it could increase geothermal energy production and offset atmospheric emissions of greenhouse gases. However, the impact of geochemical reactions between acidic waters in equilibrium with supercritical CO2 and the reservoir rock have not been evaluated. At issue are enhanced rock-water interactions that may reduce reservoir porosity and permeability and may exacerbate downstream scaling.

The publications included in this submission aim to assess the geochemical impact of CO2 on geothermal energy production by analyzing the geochemistry of existing geothermal fields with elevated natural CO2, to measure realistic rock-water rates for geothermal systems using laboratory and field-based experiments, and to develop reactive transport models using the filed-based rates to simulate production scale impacts.