A simplified model for heat extraction by circulating fluid through a closed-loop multiple-fracture enhanced geothermal system

2016 ◽  
Vol 183 ◽  
pp. 1664-1681 ◽  
Author(s):  
Bisheng Wu ◽  
Xi Zhang ◽  
Robert G. Jeffrey ◽  
Andrew P. Bunger ◽  
Shanpo Jia
Keyword(s):  
Closed Loop ◽  
Heat Extraction ◽  
Simplified Model ◽  
Geothermal System ◽  
Enhanced Geothermal System ◽  
Multiple Fracture

scholarly journals Performance Analysis of Single-Well Enhanced Geothermal System for Building Heating

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Haijun Liang ◽  
Xiaofeng Guo ◽  
Tao Gao ◽  
Lingbao Wang ◽  
Xianbiao Bu
Keyword(s):  
Volume Flow Rate ◽  
Water Reservoir ◽  
Hot Water ◽  
Heat Extraction ◽  
Geothermal System ◽  
Enhanced Geothermal System ◽  
Artificial Reservoir ◽  
Reservoir Volume ◽  
Thermal Output ◽  
Single Well

Deep borehole heat exchanger (DBHE) technology does not depend on the existence of hot water reservoir and can be used in various regions. However, the heat extraction from DBHE can hardly be improved due to poor thermal conductivity of rocks. Here, a single-well enhanced geothermal system (SWEGS) is proposed, which has a larger heat-exchange area of artificial reservoir created by fracturing hydrothermal technology. We find that, due to heat convection between rocks and fluid, the extracted thermal output for SWEGS is 4772.73 kW, which is 10.64 times of that of DBHE. By changing the injection water temperature, volume flow rate, and artificial reservoir volume, it is easy to adjust the extracted thermal output to meet the requirement of building thermal loads varying with outdoor air temperature. Understanding these will enable us to better apply SWEGS technology and solve the fog and haze problem easily and efficiently.

scholarly journals Numerical evaluation of building heating potential from a co-axial closed-loop geothermal system using wellbore–reservoir coupling numerical model

2019 ◽  
Vol 38 (3) ◽  
pp. 733-754 ◽  
Author(s):  
Tianfu Xu ◽  
Zixu Hu ◽  
Bo Feng ◽  
Guanhong Feng ◽  
Fengyu Li ◽  
...  
Keyword(s):  
Geothermal Energy ◽  
Closed Loop ◽  
Heating System ◽  
Coupling Model ◽  
Production Performance ◽  
Heat Extraction ◽  
Geothermal System ◽  
Renewable Energy Resources ◽  
Practical Engineering ◽  
System Maintenance

Geothermal energy is one of the most potential renewable energy resources. How to efficiently extract and utilize geothermal energy has been a worldwide hot topic. Co-axial closed-loop geothermal system is a novel method using a continuously closed wellbore without water exchange with. It is more suitable for reservoirs with medium or low temperature and permeability because many problems could be avoided such as lack of in situ groundwater or low infectivity of the reservoir. Many companies and research institutes have applied closed-loop geothermal system in building heating engineering and some fine results have been gained. However, in practical engineering construction, the area of a closed-loop geothermal system heating system is a very important parameter. It directly determines the cost accounting and initial design of the project. Accurate and reliable estimation of heating capacity becomes very important. In this study, a wellbore–reservoir coupling model is established, which is calibrated using measured data from a short-term field trial operation. We have carried out mixed convective–conductive fluid-flow modeling using a wellbore flow model for TOUGH2 called T2Well to investigate the heat extraction performance of closed-loop geothermal system. The system evolution and the effect of flow rate and injection temperature on heat production performance are discussed. The result shows that the intermittent production cycles are more beneficial for heat extraction and system maintenance, and the temperature recovery between two heating seasons is enough to maintain system heating. And we can calculate that a geothermal well can ensure heating of buildings of 10,000–20,000 m2 and the heating area of intermittent operation is 4000 m2 more than continuous operation. Besides, the sensitivity analysis of parameters is also carried out.

Numerical investigation on heat extraction performance of a CO2 enhanced geothermal system with multilateral wells

Energy ◽  
2018 ◽  
Vol 163 ◽  
pp. 38-51 ◽  
Author(s):  
Yu Shi ◽  
Xianzhi Song ◽  
Zhonghou Shen ◽  
Gaosheng Wang ◽  
Xiaojiang Li ◽  
...  
Keyword(s):  
Numerical Investigation ◽  
Heat Extraction ◽  
Geothermal System ◽  
Enhanced Geothermal System ◽  
Extraction Performance

scholarly journals An Approximate Solution for Predicting the Heat Extraction and Preventing Heat Loss from a Closed-Loop Geothermal Reservoir

Geofluids ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-17 ◽  
Author(s):  
Bisheng Wu ◽  
Tianshou Ma ◽  
Guanhong Feng ◽  
Zuorong Chen ◽  
Xi Zhang
Keyword(s):  
Closed Loop ◽  
Dominant Role ◽  
Approximate Solutions ◽  
Injection Rate ◽  
Geothermal Reservoir ◽  
Heat Extraction ◽  
Geothermal System ◽  
Fluid Viscosity ◽  
Vertical Wells ◽  
Output Performance

Approximate solutions are found for a mathematical model developed to predict the heat extraction from a closed-loop geothermal system which consists of two vertical wells (one for injection and the other for production) and one horizontal well which connects the two vertical wells. Based on the feature of slow heat conduction in rock formation, the fluid flow in the well is divided into three stages, that is, in the injection, horizontal, and production wells. The output temperature of each stage is regarded as the input of the next stage. The results from the present model are compared with those obtained from numerical simulator TOUGH2 and show first-order agreement with a temperature difference less than 4°C for the case where the fluid circulated for 2.74 years. In the end, a parametric study shows that (1) the injection rate plays dominant role in affecting the output performance, (2) higher injection temperature produces larger output temperature but decreases the total heat extracted given a specific time, (3) the output performance of geothermal reservoir is insensitive to fluid viscosity, and (4) there exists a critical point that indicates if the fluid releases heat into or absorbs heat from the surrounding formation.

Improving heat extraction performance of an enhanced geothermal system utilizing cryogenic fracturing

Geothermics ◽  
2020 ◽  
Vol 85 ◽  
pp. 101816
Author(s):  
Hongyuan Zhang ◽  
Zhongwei Huang ◽  
Shikun Zhang ◽  
Zheqi Yang ◽  
John D. Mclennan
Keyword(s):  
Heat Extraction ◽  
Geothermal System ◽  
Enhanced Geothermal System ◽  
Cryogenic Fracturing ◽  
Extraction Performance
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