Impacts of fracture network geometries on numerical simulation and performance prediction of enhanced geothermal systems

Liu, Gang; Zhou, Chunwei; Rao, Zhenghua; Liao, Shengming

doi:10.1016/j.renene.2021.02.070

Cited by 55 publications

(5 citation statements)

References 40 publications

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“…Many EGS fracturing test results indicated that the permeability of the fractured geothermal reservoir was heterogeneous. Generally, the reservoir permeability around the wellbore was greatly larger than that in the far well area [44,45]. This phenomenon has also Energies 2023, 16, 7202 6 of 16 been observed during hydraulic fracturing in the Gonghe Basin EGS site [46], as shown in Figure 3.…”

Section: Model Geometry and Numerical Discretizationmentioning

confidence: 59%

“…The heat conductivity and specific heat of the rock were 3 W/(m• • C) and 980 J/(kg• • C), respectively. For the fractured reservoir, the permeability in the outermost (k f1 ), middle (k f2 ) and innermost (k f3 ) fractions were assumed to be 50 mD, 75 mD, and 100 mD, respectively [44]. The porosity in the fractured reservoir was assumed to be 0.5.…”

Section: Model Parametersmentioning

confidence: 99%

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Heat Production Performance from an Enhanced Geothermal System (EGS) Using CO2 as the Working Fluid

Zhao,

Yuan,

Jing

et al. 2023

Energies

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CO2-based enhanced geothermal systems (CO2-EGS) are greatly attractive in geothermal energy production due to their high flow rates and the additional benefit of CO2 geological storage. In this work, a CO2-EGS model is built based on the available geological data in the Gonghe Basin, Northwest China. In our model, the wellbore flow is considered and coupled with a geothermal reservoir to better simulate the complex CO2 flow and heat production behavior. Based on the fractured geothermal reservoir at depths between 2900 m and 3300 m, the long-term (30-year) heat production performance is predicted using CO2 as the working fluid with fixed wellhead pressure. The results indicate that the proposed CO2-EGS will obtain an ascending heat extraction rate in the first 9 years, followed by a slight decrease in the following 21 years. Due to the significant natural convection of CO2 (e.g., low viscosity and density) in the geothermal reservoir, the mass production rate of the CO2-EGS will reach 150 kg/s. The heat extraction rates will be greater than 32 MW throughout the 30-year production period, showing a significant production performance. However, the Joule–Thomson effect in the wellbore will result in a drastic decrease in production temperature (e.g., a 62.6 °C decrease in the production well). This means that the pre-optimization analyses and physical material treatments are required during geothermal production using CO2 as the working fluid.

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Section: Model Geometry and Numerical Discretizationmentioning

confidence: 59%

Section: Model Parametersmentioning

confidence: 99%

Heat Production Performance from an Enhanced Geothermal System (EGS) Using CO2 as the Working Fluid

Zhao,

Yuan,

Jing

et al. 2023

Energies

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“…Figures 10, 11 jointly reveal that geothermal research started with concept establishment, geophysical exploration, and geochemical exploration in the early stages (Studt and Thompson, 1969;Ólafur and Saemundsson, 1993;Tanaka, 2004) and then focused on the utilization and improvement of the thermal performance of hydrothermal geothermal resources (Qin et al, 2005;Han et al, 2010;Aneke et al, 2011;Saar, 2011). In recent years, mathematical statistics and big data analytics have been combined to generate numerical simulations and system optimizations of geothermal resources to attain the use and development of hot dry rock resources (Zeng et al, 2017;Song et al, 2018;Zhou et al, 2019;Liu et al, 2021;Aliyu and Archer, 2021;Zinsalo et al, 2021) and promote the establishment of geothermal power stations.…”

Section: Theme Evolutionmentioning

confidence: 99%

Visualization Analysis on the Current Status and Development Trend of Geothermal Research: Insights Into the Database of Web of Science

2022

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Geothermal energy is considered a renewable, clean, and environmentally friendly energy source. In addition, it is efficient and relatively cost effective. Therefore, the demand for the development and utilization of geothermal resources is increasing annually. To understand the current status and developments within the context of geothermal research, quantitative and qualitative analyses were carried out by combining two visualization software applications, namely, VOSviewer and CiteSpace; this analysis also entailed the secondary development of R language. The results showed that the USA, China, and Germany are the main contributors to geothermal research. We also found that geothermal research hot spots encompass five geothermal research clusters, such as renewable energy utilization, heat flow, numerical simulation, geochemistry, and groundwater. In addition, the strategic diagram and thematic structure revealed how geothermal research has evolved over time. Finally, the timeline view and burst term highlight the possible frontiers of geothermal power generation, enhanced geothermal systems, and ecological environment protection. These insights will provide scholars and policymakers with a systematic understanding of the current research and directions for future studies.

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“…This process aims to establish pathways for fluid flow and heat exchange within deep geothermal reservoirs, enabling the extraction of high-quality heat for direct utilization in urban heating or power generation. Thus, the overall heat production of an EGS strongly relies on the efficient connection of the fracture systems [3]. A single fracture serves as the basic component of the fracture network and is critical for simulation, analysis and evaluation [4].…”

Section: Introductionmentioning

confidence: 99%

Study on Flow and Heat Transfer in Single Rock Fractures for Geothermal Heat Extraction

Li,

Liu,

Liao

2024

Processes

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A full understanding of the fluid flow and heat transfer behaviors within a single fracture is important for geothermal heat extraction. In this study, models of single fractures with varying aperture and inner surface roughness (characterized by fractal dimension) are constructed, and a compound fracture aperture (CFA) is proposed to describe the coupled effect of fracture aperture and inner surface roughness. The effect of the fluid flow Reynolds number on heat transfer was investigated as it ranged from 4.84 to 145.63. The results show that the overall heat transfer coefficient (OHTC) in a single fracture significantly increases with the rise in fluid velocity and the compound fracture aperture. Particularly, the OHTC in a single fracture with an inner surface fractal dimension of 2.09 can be up to 1.215 times that of a parallel flat fracture when the flow velocity reaches 0.18 m/s. Moreover, for a fracture with a smaller CFA, enhancing the fracture aperture plays a decisive role in increasing the OHTC. Aperture emerges as a more sensitive optimization parameter for efficient heat extraction compared to the flow velocity. Meanwhile, based on simulation results, a convective heat transfer correlation equation is derived to provide more accurate estimates of the OHTC in rock fractures with different geometries and morphological features.

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Impacts of fracture network geometries on numerical simulation and performance prediction of enhanced geothermal systems

Cited by 55 publications

References 40 publications

Heat Production Performance from an Enhanced Geothermal System (EGS) Using CO2 as the Working Fluid

Heat Production Performance from an Enhanced Geothermal System (EGS) Using CO2 as the Working Fluid

Visualization Analysis on the Current Status and Development Trend of Geothermal Research: Insights Into the Database of Web of Science

Study on Flow and Heat Transfer in Single Rock Fractures for Geothermal Heat Extraction

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