Potential assessment of CO2 injection for heat mining and geological storage in geothermal reservoirs of China

• Published in: Applied energy Vol. 122; pp. 237 - 246
• Main Authors: Zhang, Liang, Ezekiel, Justin, Li, Dexiang, Pei, Jingjing, Ren, Shaoran
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-06-2014; Elsevier
• Subjects: Applied sciences; Carbon dioxide; Crude oil, natural gas and petroleum products; Crude oil, natural gas, oil shales producing equipements and methods; Energy; Enhanced oil recovery methods; Exact sciences and technology; Fuels; Geothermal reservoir; Heat mining potential; Prospecting and production of crude oil, natural gas, oil shales and tar sands; Reservoir simulation; Storage capacity; Asia; China; Storage capacity; Heat mining potential; Carbon dioxide; Geothermal reservoir; Reservoir simulation; Storage; Simulation; Enhanced recovery; Carbon dioxide injection
• ISSN: 0306-2619; 1872-9118
• DOI: 10.1016/j.apenergy.2014.02.027

•Three types of geothermal reservoir are potential sites suitable for CO2 injection.•Artificially created HDR reservoirs will not provide much CO2 storage potential.•Sedimentary geothermal reservoirs have large pores which benefit for heat mining.•A simple method is presented for calculating recoverable geothermal potential China.•HDR reservoir selection and CO2 loss to surrounding formation need further studies.
Supercritical CO2 has good mobility and certain heat capacity, which can be used as an alternative of water for heat recovery from geothermal reservoirs, meanwhile trapping most of injected CO2 underground to achieve the environmental benefits. In this paper, different types of geothermal resources are assessed to screen reservoirs suitable for heat mining and geological storage by CO2 injection, in terms of geological properties, heat characteristics, storage applicability, and development prospects, etc. Hot dry rock, deep saline aquifer, and geopressured reservoir are selected as the potential sites for this study, mainly due to their relatively positive geological conditions for CO2 circulation and storage. Reservoir simulations are conducted to analyze the heat extracting capacity and storage efficiency of CO2 in the promising geothermal reservoirs. A simple calculation method is presented to estimate the potentials of heat mining and CO2 storage in the major prospective geothermal regions of China. The preliminary assessment results show that the recoverable geothermal potential by CO2 injection in China is around 1.55×1021J with hot dry rocks as the main contributor. The corresponding CO2 storage capacity is up to 3.53×1014kg with the deep saline aquifers accounting for more than 50%. CO2 injection for geothermal production is a more attractive option than pure CO2 storage due to its higher economic benefits in spite of that many technological and economic issues still need to be solved in the future.