18.10.2014: Pressure management in CO2 storage reservoirs by brine production
Nowadays, water and gas storage in porous sandstones at depth is state-of-the-art. However, any storage in the geological underground increases the pressure in the pores of the storage formation rocks. Consequently, saline formation water present in the pores is displaced by the injected fluid. Furthermore, pore pressure elevation often results in ground surface uplift. One approach to tackle this problem is formation water extraction to generate void for the stored fluid.
A present study carried out by an international team of scientists including Thomas Kempka (GFZ German Research Centre for Geosciences) investigated how a targeted extraction of formation fluids from the storage formation can reduce these negative impacts. Based on coupled numerical simulations, it was demonstrated that pore pressure elevation in the storage formation can be mitigated by formation water extraction, so that ground surface uplift is reduced by up to 37 % at the injection and completely avoided at the production wells.
The extracted deep formation water is warm, and thus further studies focus on feasibility of heat extraction from that fluid. Synergetic utilization of underground storage formations can increase the geothermal heat recovery efficiency.
Thomas Kempka et al.: “Coupled Hydro-Mechanical Simulations of CO2 Storage Supported by Pressure Management Demonstrate Synergy Benefits from Simultaneous Formation Fluid Extraction”, Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles, 14.10.2014