Present status and remaining problems of HDR/HWR system design

Abé, Hiroyuki; Duchane, David V.; Parker, R. H.; Kuriyagawa, Michio

doi:10.1016/s0375-6505(99)00029-2

Cited by 12 publications

(5 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Numerical simulation results presented in this paper confirm advantages of CO 2 over water as heat transmission fluid for enhanced geothermal systems (EGS), predicting larger energy extraction rates for CO 2 for the same applied pressures in injection and production wells. The mobility (= density/viscosity) of CO 2 depends in complicated fashion on both temperature and pressure, which gives rise to unusual features in the time dependence of mass flow and heat extraction rates.…”

Section: Discussionsupporting

confidence: 59%

“…As pointed out by Brown, CO 2 has certain thermophysical and chemical properties that could make it attractive as a heat transfer medium. Water losses present a serious obstacle to commercialization of water-based EGS [2], while fluid losses in an EGS operated with CO 2 could achieve geologic storage of CO 2 as an ancillary benefit. An additional motivating factor for exploring CO 2 as working fluid is that water-based EGS face significant technical difficulties from mineral dissolution and precipitation, due to strong chemical interactions between rocks and aqueous fluids at geothermal temperatures [3][4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

On production behavior of enhanced geothermal systems with CO2 as working fluid

Pruess

2008

Energy Conversion and Management

225

View full text Add to dashboard Cite

Numerical simulation is used to evaluate mass flow and heat extraction rates from enhanced geothermal injection-production systems that are operated using either CO 2 or water as heat transmission fluid. For a model system patterned after the European hot dry rock experiment at Soultz, we find significantly greater heat extraction rates for CO 2 as compared to water. The strong dependence of CO 2 mobility (= density/viscosity) upon temperature and pressure may lead to unusual production behavior, where heat extraction rates can actually increase for a time, even as the reservoir is subject to thermal depletion. We present the first-ever three-dimensional simulations of CO 2 injection-production systems. These show strong effects of gravity on mass flow and heat extraction, due to the large contrast of CO 2 density between cold injection and hot production conditions. The tendency for preferential flow of cold, dense CO 2 along the reservoir bottom can lead to premature thermal breakthrough. The problem can be avoided by producing from only a limited depth interval at the top of the reservoir.-2 -

show abstract

Section: Discussionsupporting

confidence: 59%

Section: Introductionmentioning

confidence: 99%

On production behavior of enhanced geothermal systems with CO2 as working fluid

Pruess

2008

Energy Conversion and Management

225

View full text Add to dashboard Cite

show abstract

“…For conventional EGS projects, water is used as the circulating fluid to extract thermal energy (ie, H 2 O‐EGS). However, H 2 O‐EGS projects are associated with some problems, with regard to the amount of water loss, forming scale in ground conveying pipes, and heat exchange equipment . Thus, the use of supercritical CO 2 (SCCO 2 ) instead of water as the heat extraction fluid was proposed .…”

Section: Introductionmentioning

confidence: 99%

Effects of injection parameters on heat extraction performance of supercritical CO₂ in enhanced geothermal systems

Liu

et al. 2019

Energy Science & Engineering

View full text Add to dashboard Cite

Supercritical CO 2 (SCCO 2 ) is considered as a promising alternative heat extraction fluid in the enhanced geothermal system (EGS) which can reduce atmospheric CO 2 emissions and water waste. However, the heat extraction performance of SCCO 2 is greatly affected by its thermophysical properties, which are high sensitivity to temperature/pressure. In this study, by considering the impacts of temperature and pressure on thermophysical properties of SCCO 2 , a thermo-hydro-mechanical coupling numerical model was established to investigate the effects of the initial reservoir temperature as well as the SCCO 2 injection pressure and temperature on heat extraction. The variations of reservoir permeability and mass productivity as well as the net heat extraction rate (HER) were simulated by implementing the model into COMSOL Multiphysics, which showed a good consistency compared with the hightemperature/pressure triaxial seepage experiments. Simulation results indicate that there are three distinct stages in mass productivity including the slow decline stage, the rapid increase stage, and the stabilization stage. Increasing the initial reservoir temperature or the injection temperature will reduce the net HER to varying degrees.Appropriate increase of the injection pressure and injection temperature can extend Stage 2 duration which can subsequently enhance the mass productivity and the net HER. Meanwhile, the higher injection pressure or the lower injection temperature will inhibit heat compensation within rock masses and accelerate the reservoir heat depletion. This study provides guidance for optimizing the injection parameters of CO 2 -EGS and aims to enhance the net HER while ensuring a reasonable reservoir production life. K E Y W O R D S enhanced geothermal system, heat extraction experiment, high temperature/pressure, numerical simulation, supercritical CO 2 How to cite this article: Li P, Wu Y, Liu J-F, et al. Effects of injection parameters on heat extraction performance of supercritical CO 2 in enhanced geothermal systems. Energy Sci Eng. 2019;7:3076-3094. https ://doi.

show abstract

“…Conventional EGS uses water as the heat-carrying medium, and there are a lot of researches on this technology at home and abroad [8][9][10][11]; it is found that the heat extraction of H 2 O-EGS has great advantages in the presence of in situ fluid in the reservoir [12]. However, some scholars pointed out that the use of H 2 O-EGS will cause a lot of water resource loss [13] and also cause a series of problems that are not conducive to the operation and maintenance of geothermal system [14][15][16][17]. To solve these problems, in 2000, Brown first proposed that it can use supercritical CO 2 (SCCO 2 ) instead of water as a heat-carrying medium [18].…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation on Heat Recovery Efficiency of Different Working Fluids in High-Temperature Rock Mass

Geng

Guan

et al. 2021

Geofluids

View full text Add to dashboard Cite

It is of great significance for the sustainable development of global energy to develop hot dry rock (HDR) geothermal resources by using enhanced geothermal system (EGS) technology. Different working fluids in EGS have different heat recovery efficiencies. Therefore, this paper takes water and CO2 as the heat-carrying media and establishes a thermal hydraulic mechanical coupling model to simulate the heat recovery process in high-temperature rock mass. By considering the different confining pressures, rock temperature, and injection pressure, the advantages of H2O-EGS and CO2-EGS are obtained. The results show that with the increase of confining pressure, the heat recovery efficiency of water is significantly higher than that of CO2, but at higher reservoir temperature, CO2 has more advantages as a heat-carrying medium. The net heat extraction rate will increase with the increase of injection pressure, which indicates that the mass flow rate plays a leading role in the heat recovery process and increases the injection pressure of fluid which is more conducive to the thermal recovery of EGS. This study will provide a technical guidance for thermal energy exploitation of hot dry rock under different geological conditions.

show abstract

Present status and remaining problems of HDR/HWR system design

Cited by 12 publications

References 0 publications

On production behavior of enhanced geothermal systems with CO2 as working fluid

On production behavior of enhanced geothermal systems with CO2 as working fluid

Effects of injection parameters on heat extraction performance of supercritical CO₂ in enhanced geothermal systems

Numerical Simulation on Heat Recovery Efficiency of Different Working Fluids in High-Temperature Rock Mass

Contact Info

Product

Resources

About

Present status and remaining problems of HDR/HWR system design

Cited by 12 publications

References 0 publications

On production behavior of enhanced geothermal systems with CO2 as working fluid

On production behavior of enhanced geothermal systems with CO2 as working fluid

Effects of injection parameters on heat extraction performance of supercritical CO2 in enhanced geothermal systems

Numerical Simulation on Heat Recovery Efficiency of Different Working Fluids in High-Temperature Rock Mass

Contact Info

Product

Resources

About

Effects of injection parameters on heat extraction performance of supercritical CO₂ in enhanced geothermal systems