Influence of thermal compensation of geothermal reservoir rock formation on CO2 plume geothermal system performance
【Abstract】Carbon dioxide plume geothermal system (CPGS) can be used to exploit geothermal energy and realize carbon dioxide geological sequestration simultaneously. The thermal compensation from the rock formation around the geothermal reservoir is one of the important factors that affect the performance of CPGS. Based on a three dimensional base and cap rocks enclosed heat reservoir model, the influences of the thermal compensation on the temperature evolutionary process of the rock and fluid in the geothermal reservoir and the heat collection performance of CPGS were studied. The distribution of geothermal reservoir temperature and the temperature of production fluid were compared with those without consideration of the thermal compensation. The results showed that the thermal compensation reduced both the production fluid temperature variation along the vertical direction and its temperature decreasing rate in the later period of system operation, and therefore extended the lifetime of CPGS and gains better heat collection performance. With consideration of the thermal compensation, the heat production was improved significantly. The results also showed that the thermal compensation of the base rocks was stronger than that of the cap rocks.
【Keywords】 rock formation; geothermal reservoir; thermal compensation; carbon dioxide; geothermal system; porous media; numerical simulation;
(Translated by LIANG T)
 HOLLOWAY S. Storage of fossil fuel-derived carbon dioxide beneath the surface of the Earth [J]. Annual Review Energy Environment, 2001, 26: 145–166.
 WEST J M, PEARCE J, BENTHAM M, et al. Issue profile: environmental issues and the geological storage of CO2 [J]. European Environment, 2005, 15: 250–259.
 GENTZIS T. Subsurface sequestration of carbon dioxide—an overview from an Alberta (Canada) perspective [J]. International Journal of Coal Geology, 2000, 43: 287–305.
 GOUGH C. State of the art in carbon dioxide capture and storage in the UK: an experts’ review [J]. International Journal of Greenhouse Gas Control, 2008, 2: 155–168.
 HOLLOWAY S. Underground sequestration of carbon dioxide—a viable greenhouse gas mitigation option [J]. Energy, 2005, 30: 2318–2333.
 METZ B, DAVIDSON O R, BOSCH P R, et al. Contribution of working group Ⅲ to the fourth assessment report of the intergovernmental panel on climate change [R]. Cambridge: Cambridge University Press, 2007.
 BROWN D. A hot dry rock geothermal energy concept utilizing supercritical CO2 instead of water [C] //Proceedings of the Twenty-Fifth Workshop on Geothermal Reservoir Engineering, Stanford, 2000: 233–238.
 PRUESS K. Enhanced geothermal systems (EGS) using CO2 as working fluid—a novel approach for generating renewable energy with simultaneous sequestration of carbon [J]. Geothermics, 2006, 35: 351–367.
 PRUESS K. Enhanced geothermal systems (EGS) comparing water with CO2 as heat transmission fluids [R]. Lawrence Berkeley National Laboratory, 2007.
 PRUESS K. On the feasibility of using supercritical CO2 as heat transmission fluid in an engineered hot dry rock geothermal system thirty-first workshop on geothermal reservoir engineering: SGP-TR-179 [R]. California: Stanford University, 2006.
 PRUESS K. On production behavior of enhanced geothermal systems with CO2 as working fluid [J]. Energy Conversion and Management, 2008, 49 (6): 1446–1454.
 MAJER E L, BARIA R, STARK M, et al. Induced seismicity associated with enhanced geothermal systems [J]. Geothermics, 2007, 36: 185–222.
 GLANZ J. Deep in bedrock, clean energy and quake fears [N]. New York: New York Times, 2009-06-23 (1).
 RANDOLPH J B, SAAR M O. Coupling geothermal energy capture with carbon dioxide sequestration in naturally permeable, porous geologic formations: a comparison with enhanced geothermal systems [J]. GRC Trans., 2010, 34: 433–438.
 RANDOLPH J B, SAAR M O. Combining geothermal energy capture with geologic carbon dioxide sequestration [J]. Geophys Res. Lett., 2011, 38 (10): 415–421.
 RANDOLPH J B, SAAR M O. Coupling carbon dioxide sequestration with geothermal energy capture in naturally permeable, porous geologic formations: implications for CO2 sequestration [J]. Energy Procedia, 2011, 4: 2206–2213.
 ZHANG L, EZEKIEL J, LI D X, et al. Potential assessment of CO2 injection for heat mining and geological storage in geothermal reservoirs of China [J]. Applied Energy, 2014, 122: 237–246.
 XU T F, FENG G H, SHI Y. On fluid–rock chemical interaction in CO2-based geothermal systems [J]. Journal of Geochemical Exploration, 2014, 144: 179–193.
 CHEN J L, LUO L, JIANG F M. Thermal compensation of rocks encircling heat reservoir in heat extraction of enhanced geothermal system [J]. Chinese Journal of Computational Physics, 2013, 30 (6): 862–870 (in Chinese).
 CHEN J L, JIANG F M. A numerical study on heat extraction performance of enhanced geothermal systems [J]. Renewable Energy Resources, 2013, 31 (12): 111–117 (in Chinese).
 FENG G H, LI J Q, XU T F, et al. Effects of property of reservoir on heat extraction in CO2 plume geothermal system [J]. Renewable Energy Resources, 2013, 31 (7): 85–92 (in Chinese).
 WEI M C, YANG B, XU T F, et al. Effects of well spacing and reservoir permeability on heat extraction in CO2 plume geothermal system: a case study of Songliao basin [J]. Geological Science and Technology Information, 2015, 34 (2): 188–193 (in Chinese).
 REN S R, CUI G D, LI D X, et al. Development of geothermal energy from depleted high temperature gas reservoir via supercritical CO2 injection [J]. Journal of China University of Petroleum (Edition of Natural Science), 2016, 40 (2): 91–98 (in Chinese).
 GARAPATI N, RANDOLPH J B, JOSE L, et al. CO2-plume geothermal (CPG) heat extraction in multi-layered geologic reservoirs [J]. Energy Procedia, 2014, 63: 7631–7643.
 GARAPATI N, RANDOLPH J B, SAAR M O. Brine displacement by CO2, energy extraction rates, and lifespan of a CO2-limited CO2-Plume Geothermal (CPG) system with a horizontal production well [J]. Geothermics, 2015, 55: 182–194.
 SHI Y, WANG F G, YANG Y L, et al. Use of a CO2 geological storage system to develop geothermal resources: a case study of a sandstone reservoir in the Songliao basin of northeast China [M] //HOU M Z, XIE H P, WERE P. Clean Energy Systems in the Subsurface: Production, Storage and Conversion. Berlin: Springer, 2013: 89–103.
 ADAMS B M, KUEHN T H, BIELICKI J M, et al. On the importance of the thermosiphon effect in CPG (CO2 plume geothermal) power systems [J]. Energy, 2014, 69: 409–418.
 ADAMS B M, KUEHN T H, BIELICKI J M, et al. A comparison of electric power output of CO2 Plume Geothermal (CPG) and brine geothermal systems for varying reservoir conditions [J]. Applied Energy, 2015, 140: 365–377.
 CHEN J L, JIANG F M. A numerical study of EGS heat extraction process based on a thermal non-equilibrium model for heat transfer in subsurface porous heat reservoir [J]. Heat and Mass Transfer, 2016, 52: 255–267.
 JIANG F M, CHEN J L, HUANG W B, et al. A three-dimensional transient model for EGS subsurface thermo-hydraulic process [J]. Energy, 2014, 72: 300–310.
 CHEN J L, JIANG F M. Designing multi-well layout for enhanced geothermal system to better exploit hot dry rock geothermal energy [J]. Renewable Energy, 2015, 74: 37–48.
 CAO W J, HUANG W B, JIANG F M. Numerical study on variable thermophysical properties of heat transfer fluid affecting EGS heat extraction [J]. International Journal of Heat and Mass Transfer, 2016, 92: 1205–1217.
 FAGERLUND F F, NIEMI A, ODEN M. Comparison of relative permeability–fluid saturation–capillary pressure relations in the modelling of non-aqueous phase liquid infiltration in variably saturated, layered media [J]. Advances in Water Resources, 2006, 29 (11): 1705–1730
 YANG Y L, JING J, WANG F G, et al. Optimal design of well spacing on CO2 enhanced geothermal [J]. Acta Energiae Solaris Sinica, 2014, (7): 1130–1137 (in Chinese).
 ZHANG J H, LIU J. Probe into the optimal design of coal-bed methane well network [J]. Sci-tech Information Development & Economy, 2008, (10): 210–212 (in Chinese).