Article
Green & Sustainable Science & Technology
Yu Wu, Pan Li, Yang Hao, Ayal Wanniarachchi, Yan Zhang, Shuhua Peng
Summary: The study investigated the heat extraction and CO2 storage in hot dry rock using CO2-EGS technology through a series of experiments. The findings revealed the mechanism of CO2 storage and its potential applications in the future.
Article
Energy & Fuels
Marco Taussi, Andrea Brogi, Domenico Liotta, Barbara Nisi, Maddalena Perrini, Orlando Vaselli, Miller Zambrano, Martina Zucchi
Summary: This study conducted a detailed investigation on the diffusion degassing of CO2 in the geothermal system of Tuscany, Italy. By measuring soil temperature and fracture parameters, it was found that soil degassing is controlled by multiple transport mechanisms, and areas with high CO2 emissions are consistent with the distribution of fractures and characteristics of rock formations, indicating major upflow areas through deep-reaching permeable fault zones.
Article
Green & Sustainable Science & Technology
Chunwei Zhou, Gang Liu, Shengming Liao
Summary: Successful enhanced geothermal systems depend on fluid flow in fractured reservoir with good fissure connectivity. The study proposes a fuzzy inversion model to explore the location of the predominant flow area. The model achieves good inversion results, reduces dependence on initial guess area and property, and has good anti-interference ability.
JOURNAL OF CLEANER PRODUCTION
(2023)
Article
Energy & Fuels
Ryota Takahashi, Jiajie Wang, Noriaki Watanabe
Summary: Chemical stimulation using eco-friendly chelating agents for selective mineral dissolution has been proposed as a complement to hydraulic stimulation in geothermal reservoirs. This study investigates the permeability enhancement and optimum pH during stimulation experiments on fractured granite using GLDA at different pH levels. The results show that the highest permeability enhancement occurs at pH 4 due to preferential flow paths formed by selective dissolution of biotite. Silica precipitation and suppressed selective dissolution of biotite at lower and higher pH values, respectively, result in decreased permeability enhancement. The combination of pH 4 and pH 8 results in more than a 2-fold permeability enhancement in 4 hours. These findings strengthen the possibility and effectiveness of the chemical stimulation method for enhanced geothermal systems worldwide.
Article
Engineering, Chemical
Yuchao Zeng, Fangdi Sun, Haizhen Zhai
Summary: The vertical permeability heterogeneity in stratified formations significantly influences the electricity generation performance of enhanced geothermal systems, affecting water production rate, electric power, reservoir impedance, and pump power. However, vertical permeability heterogeneity is not the main factor affecting injection pressure and energy efficiency in the system.
Article
Green & Sustainable Science & Technology
Gaosheng Wang, Xiaodong Ma, Xianzhi Song, Gensheng Li
Summary: The enhanced geothermal system plays a key role in developing deep geothermal resources, and understanding the flow and heat transfer in fractures is crucial for its efficient operation.
JOURNAL OF CLEANER PRODUCTION
(2022)
Review
Green & Sustainable Science & Technology
Zhennan Zhu, Shengqi Yang, Pathegama Gamage Ranjith, Wenling Tian, Hong Tian, Jun Zheng, Guosheng Jiang, Bin Dou
Summary: This research analyzed and determined the changes in the mechanical characteristics of granites after various thermal shocks through a comprehensive review of research. The change mechanisms of the mechanical responses of granites after various thermal shocks were revealed by microstructural observations. The macroscale deterioration of the mechanical parameters of various granites after thermal shocks is closely associated with the initiation, development, and coalescence of microcracks.
JOURNAL OF CLEANER PRODUCTION
(2023)
Article
Energy & Fuels
Wentao Zhao, Yilong Yuan, Tieya Jing, Chenghao Zhong, Shoucheng Wei, Yulong Yin, Deyuan Zhao, Haowei Yuan, Jin Zheng, Shaomin Wang
Summary: This study builds a CO2-EGS model based on geological data in the Gonghe Basin of Northwest China to predict the long-term heat production performance. The results show an increasing heat extraction rate in the first 9 years and a slight decrease in the following 21 years. Due to the natural convection of CO2 in the geothermal reservoir, the CO2-EGS achieves a mass production rate of 150 kg/s and a heat extraction rate greater than 32 MW throughout the 30-year production period. However, the Joule-Thomson effect in the wellbore causes a drastic decrease in production temperature, requiring pre-optimization analyses and physical material treatments.
Article
Geochemistry & Geophysics
Haopeng Jiang, Annan Jiang
Summary: This study investigated the seepage characteristics of cut-through fractured rocks under different temperatures, analyzing the influence of temperature on permeability and fractured state. A theoretical formula for fractured seepage calculation was introduced, and numerical calculations showed good agreement with experimental results, providing guidance for research on high-temperature effects on rock fissure permeability evolution in fire tunnels.
Article
Energy & Fuels
Qi-Le Ding, Peng Wang, Zheng Cheng
Summary: This research demonstrates the significant impact of high-temperature treatments and different confining pressures on the permeability of granite. The increase in temperature has a crucial effect on crack generation and permeability, which shows three stages of change with temperature. Additionally, increasing confining pressure reduces the rate of permeability decrease.
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2022)
Article
Green & Sustainable Science & Technology
Satuk Bugra Akdas, Mustafa Onur
Summary: This study presents novel analytical solutions for predicting and optimizing energy extraction from hot-dry rock or hot-wet rock through multistage hydraulically fractured horizontal well doublet. The solutions, obtained using Laplace transformation, were validated against commercial simulator results. Sensitivity analysis was conducted to investigate the impact of parameters on heat recovery and electricity production in an EGS system stimulated by an MHFWD.
Article
Energy & Fuels
Tian Fang, Quanlin Feng, Rui Zhou, Chaobin Guo, Siqi Wang, Kun Gao
Summary: Understanding fluid flow in fractured porous media under coupled thermal-hydrological-mechanical (THM) conditions is crucial for geothermal energy extraction. This study developed a fully coupled THM model to investigate the process in fractured porous reservoirs, focusing on the importance of fracture orientation and hydraulic fracture permeability on fluid trajectories and heat extraction efficiency. Simulation results showed that hydraulic fractures govern fluid channels and thermal exchange, and interconnected natural fractures enhance water migration into the reservoir, highlighting the role of fracture connectivity in optimizing heat extraction efficiency.
JOURNAL OF PETROLEUM EXPLORATION AND PRODUCTION TECHNOLOGY
(2023)
Article
Energy & Fuels
Pan Li, Yu Wu, Ji'an Luo, Hongxue Zhang
Summary: This study established the relationship between rock thermal conductivity and temperature, proposed a local average heat transfer coefficient, and investigated the effects of confining pressure, rock sample temperature, SCCO2 injection pressure, and injection temperature on outlet temperature and local average HTC through experiments. The results provided valuable information for increasing the heat extraction rate in HDR reservoirs.
Article
Multidisciplinary Sciences
Anna Jentsch, Walter Duesing, Egbert Jolie, Martin Zimmer
Summary: This study investigated how natural gas emissions react sensitively and quickly to changes within a deep hydrothermal system, with results showing that gas emissions respond to changes in reinjection rates within 24 hours.
SCIENTIFIC REPORTS
(2021)
Article
Thermodynamics
Xianbiao Bu, Zhipeng Guo, Lingbao Wang
Summary: The proposed SDEGS enhances geothermal energy extraction by fracturing low yield hydrothermal systems to increase permeability and volume flow rate. With the ability to adjust volume flow rate and injection water temperature, it can provide heating for buildings and meet thermal load requirements under different outdoor ambient temperatures, promoting rapid development of geothermal energy and effectively solving the smog problem.
CASE STUDIES IN THERMAL ENGINEERING
(2021)