Article
Energy & Fuels
Hongwei Wang, Hejuan Liu, Dongfang Chen, Haidong Wu, Xianpeng Jin
Summary: To efficiently exploit geothermal energy, it is important to have a reasonable configuration of fracture networks that minimize water loss, while maintaining high flow rates, high production temperatures, and good connectivity between injection and production wells. The study establishes a THM coupling model to analyze the influence of factors such as formation stress, injection pressure, fracture surface roughness, fracture intersection angle, and fracture connectivity on fluid seepage pressure and outlet temperature. Comprehensive consideration of multiple parameters is crucial for the development of EGS projects and their commercial viability.
Article
Geosciences, Multidisciplinary
Feng Xiong, Chun Zhu, Gan Feng, Jun Zheng, Hao Sun
Summary: Three-dimensional fluid flow and thermal transport modeling in discrete fracture networks (DFNs) is crucial for enhanced geothermal systems (EGSs). A coupled thermo-hydro (T-H) model based on the Galerkin finite element method was developed, considering nonlinear fluid flow models and a simplified thermal transport model. The proposed method was validated using experimental, analytical, and numerical solutions, and applied to simulate heat extraction in a Habanero EGS reservoir. The results showed that injection pressure and temperature had different effects on power generation and reservoir lifespan.
Article
Environmental Sciences
Zitong Zhou, Delphine Roubinet, Daniel M. Tartakovsky
Summary: A method for inferring fracture density and fractal dimension of fractured rocks from thermal experiments data is presented. This method shows that fracture density can be well constrained by data, while fractal dimension is harder to determine. Adding nonuniform prior information related to fracture network connectivity improves the inference of fractal dimension parameter.
WATER RESOURCES RESEARCH
(2021)
Article
Thermodynamics
Xueling Liu, Lisha Zhong, Jiansheng Wang
Summary: A hot dry rock compressed air energy storage system is proposed in this paper, which utilizes the cracks of hot dry rock as the storage place for compressed air, solving the strict site requirement and fossil fuel consumption issues. The performance of the system is evaluated through thermodynamic and wellbore models, and the results indicate that the production temperature increases with the mass flow rate, while the recharge pressure has little effect on it. Moreover, the consumption of valley electricity increases with the mass flow rate and decreases with the recharge pressure. The round trip efficiency of the system fluctuates between 48.59% to 54.88%, which is much better than the traditional compressed air energy storage system.
ENERGY CONVERSION AND MANAGEMENT
(2023)
Article
Green & Sustainable Science & Technology
Musa D. Aliyu, Rosalind A. Archer
Summary: This paper presents a new three-dimensional numerical model of a hot dry rock geothermal reservoir and analyzes two case studies to determine the impact of different factors on reservoir performance, showing that wellbore placement significantly affects reservoir performance.
Article
Thermodynamics
Xueling Liu, Jintao Niu, Jiansheng Wang, Huipeng Zhang, Liwei Dong
Summary: This study investigated the coupling mechanism of a double-stage Organic Rankine Cycle (ORC) power generation system, finding that the double-stage ORC system can increase net output power while decreasing thermal efficiency, showing promising results for utilizing dry hot rock resources.
CASE STUDIES IN THERMAL ENGINEERING
(2021)
Article
Thermodynamics
Manojkumar Gudala, Suresh Kumar Govindarajan, Bicheng Yan, Shuyu Sun
Summary: This study proposes an improved mathematical model to investigate the temperature variations and mechanical strain in the Puga geothermal reservoir. It is found that there are low-temperature regions within the fractures, and the number of hydraulic fractures and well patterns significantly influence the rock and fluid properties. The proposed mathematical model can effectively evaluate and predict the changes in the reservoir.
Article
Computer Science, Interdisciplinary Applications
Zhijun Wu, Wenjun Cui, Lei Weng, Quansheng Liu
Summary: This study develops a coupled thermal-hydraulic-mechanical (THM) formulation based on the 2D combined finite-discrete element method (FDEM) to investigate the rock deformation and fracturing behavior. The formulation consists of three subsolvers for hydraulic, thermal, and mechanical properties, and is verified through benchmark problems. The results demonstrate the potential of the numerical tool in modeling THM process-driven deformation and fracturing of rock mass.
COMPUTERS AND GEOTECHNICS
(2022)
Article
Engineering, Geological
Qingxiang Meng, Haoyu Xue, Xiaoying Zhuang, Qiang Zhang, Chun Zhu, Benguo He, Gan Feng, Timon Rabczuk
Summary: A novel two-dimensional fractal discrete fracture network (DFN) generation method based on the iterative function system (IFS) was proposed for fluid flow and transport simulations. A refinement technique was presented to achieve a fine mesh for the DFN model by removing short edges and small gaps. The injection pressure of hydraulic fracture had three phases: sudden increase, rapid drop-off, and stabilization, and the fractal DFN significantly affected the injection pressure evolution and fracture propagation compared to the traditional linear DFN model. Fracture aperture variation was found to be an important factor influencing hydraulic fracturing in the rock mass. The effects of mesh sensitivity and fracture aperture size were analyzed based on two-dimensional simulation results.
ENGINEERING GEOLOGY
(2023)
Article
Engineering, Geological
Jiayao Chen, Hyungjoon Seo, Chengzhan Gao, Qian Fang, Dingli Zhang, Hongwei Huang
Summary: A comprehensive method for evaluating similarity between 2D fracture maps is proposed, including five evaluation indicators and similarity calculation based on grouping matching of trace lines. The results show that grouping similarity indicators are more rigorous and suitable for engineering modeling. The proposed method effectively solves the difficulty of comprehensive distribution similarity evaluation and achieves more objective evaluation of position and density indicators. The established evaluation system is applied to real tunnel construction, improving the accuracy of fracture modeling.
ROCK MECHANICS AND ROCK ENGINEERING
(2023)
Article
Construction & Building Technology
Shengai Cui, Enqi Cui, Wei Xia, Huijiao Zeng, Pin Liu, Meng He
Summary: This study explored the impact of surrounding rock temperature on fracture parameters of concrete through experiments. The results show that the fracture energy, initial fracture toughness, and crack extension resistance of concrete are influenced by the surrounding rock temperature, displaying different trends with temperature variations.
CONSTRUCTION AND BUILDING MATERIALS
(2021)
Article
Geosciences, Multidisciplinary
Chen Zuo, Xu Guoqing, Zhou Jian, Liu Jiankun
Summary: The study systematically analyzed the essential characteristics, rock mechanics and in-situ stress characteristics of a hot rock mass. By applying different technologies in the field, including low displacement for enhancing thermal cracking and gel fluid for expanding fracture, complex fractures were successfully formed, leading to over 3 million cubic meters of stimulation volume for heat exchanging. These research results are vital in enhancing geothermal systems and achieving breakthroughs in power generation.
ACTA GEOLOGICA SINICA-ENGLISH EDITION
(2021)
Article
Thermodynamics
Wei Zhang, Zenglin Wang, Tiankui Guo, Chunguang Wang, Fengming Li, Zhanqing Qu
Summary: This study conducted integrated research on heat mining and EGS fracturing to accurately predict EGS productivity in the HDR fracturing stage and the EGS heat mining stage. The results showed that SCO2 fracturing can reduce fracture connection time, increase damage area, and synchronous fracturing can save fracturing time and increase fracture surface area. Moreover, increasing the horizontal stress difference enhances the heat mining rate.
APPLIED THERMAL ENGINEERING
(2022)
Article
Engineering, Civil
Hongyun Fan, Liping Li, Peijun Zong, Hongliang Liu, Lanjie Yang, Jing Wang, Peng Yan, Shangqu Sun
Summary: An advanced stability analysis of surrounding rock is crucial for ensuring safe construction in tunnels. However, traditional analysis methods inaccurately treat the geometric information of rock mass discontinuities as infinitely expanded planes in numerical simulations. In this study, a control network and image stitch method were used to improve the accuracy of a geometric model, and a more accurate method based on digital photogrammetry was proposed to obtain the geometric information of rock mass discontinuities. The simulation results confirmed the specific location of collapse disasters on the tunnel face, which is significant for tunnel support design and verified the accuracy of this method in advance stability analysis.
Article
Computer Science, Interdisciplinary Applications
Yulong Liu, Zixu Hu, Tianfu Xu, Bo Feng, Yilong Yuan, Pengju Xing
Summary: A seismic-fracturing model with a discrete fracture network (DFN) was developed to study how to increase stimulated reservoir volume (SRV) while reducing seismic risks at the FORGE site in Utah. The study found that the fluid channeling effect between each segment is the main reason for uneven fracture growth in horizontal wells. To solve these problems, a novel hydraulic fracturing method with a differentiated-stage, variable-injection volume suitable for multi-fracturing of horizontal wells in hot dry rock (HDR) was proposed.
COMPUTERS AND GEOTECHNICS
(2023)
Article
Energy & Fuels
Tiankui Guo, Yuelong Zhang, Lin Shen, Xuewei Liu, Wenguang Duan, Hualin Liao, Ming Chen, Xiaoqiang Liu
Summary: This study conducted a detailed numerical simulation research on the factors affecting reservoir fracture propagation, revealing characteristics such as low permeability in low formations, minimal SC-CO2 loss, large fracture length and width, and complex fracture networks. These findings provide valuable references for construction design.
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2022)
Article
Engineering, Geological
Ming Chen, Tiankui Guo, Yushi Zou, Shicheng Zhang, Zhanqing Qu
Summary: A proppant transport simulator coupled with multi-planar 3D fracture propagation has been developed to examine the proppant distribution among multiple hydraulic fractures during multi-cluster fracturing in a horizontal well. The model considers factors such as multi-fracture stress interaction, fluid leak-off, and proppant settling, and results show that injection schedules, proppant sizes, density, and fluid viscosity all impact proppant distribution.
ROCK MECHANICS AND ROCK ENGINEERING
(2022)
Article
Energy & Fuels
Ming Chen, Tiankui Guo, Zhanqing Qu, Mao Sheng, Lijun Mu
Summary: A fully coupled fracture model is proposed to interpret the mechanism of fracture initiation and breakdown pressures. Sensitivity analysis demonstrates the dependence of initiation pressure and peak pressure on rock properties and injection conditions. A method to determine fracture initiation pressure is presented.
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2022)
Article
Energy & Fuels
Xian Shi, Weiqiang Song, Hongxing Xu, Tiankui Guo, Qihong Feng, Sen Wang, Shu Jiang
Summary: Variable density in-plane perforations in a horizontal well can create transverse fractures and prevent fracture propagation, with the in situ stress and treatment parameters significantly influencing fracture morphology and breakdown pressure.
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2022)
Article
Energy & Fuels
Ming Chen, Tiankui Guo, Shicheng Zhang, Zhanqing Qu, Yushi Zou
Summary: Understanding the interaction between hydraulic fractures (HFs) and frictional discontinuities (FDs) is crucial for interpreting microseismic events and fracture propagation. This study presents a new numerical model using a complementarity algorithm to accurately describe and determine the contact modes of FDs in HF-FD interaction. Parametric studies show that increasing the friction coefficient and strength can reduce FD slippage and increase FD opening, while increasing fluid pressure facilitates HF crossing FDs.
GEOMECHANICS AND GEOPHYSICS FOR GEO-ENERGY AND GEO-RESOURCES
(2022)
Article
Energy & Fuels
Yunkai Ji, Timothy J. Kneafsey, Jian Hou, Jianlin Zhao, Changling Liu, Tiankui Guo, Bei Wei, Ermeng Zhao, Yajie Bai
Summary: The water-gas relative permeability in hydrate-bearing porous media is crucial for understanding multiphase flow characteristics. Experimental results reveal that increasing hydrate saturation reduces the effective permeability of water and gas. However, the effect of hydrate saturation on the water-gas relative permeability differs from its effect on the effective permeability.
Article
Energy & Fuels
Xian Shi, Haoyong Huang, Bo Zeng, Tiankui Guo, Shu Jiang
Summary: Understanding the behavior of hydraulic fracture propagation and its impact on gas production is crucial for the successful development of shale gas reservoirs. This study combines hydraulic fracturing with reservoir modeling to gain insight into the complex fracture paths and consider factors such as the Langmuir isotherm effect and non-Darcy flow. It is found that the actual hydraulic fracture path has a significant impact on shale gas output, and simultaneous fracturing design schemes result in more complex fracture propagation compared to sequential hydraulic fracturing design schemes. Coupling curved hydraulic fracture stimulation with shale gas reservoir production modeling is recommended for simultaneous fracturing design schemes.
GEOMECHANICS AND GEOPHYSICS FOR GEO-ENERGY AND GEO-RESOURCES
(2022)
Article
Thermodynamics
Wei Zhang, Zenglin Wang, Tiankui Guo, Chunguang Wang, Fengming Li, Zhanqing Qu
Summary: This study conducted integrated research on heat mining and EGS fracturing to accurately predict EGS productivity in the HDR fracturing stage and the EGS heat mining stage. The results showed that SCO2 fracturing can reduce fracture connection time, increase damage area, and synchronous fracturing can save fracturing time and increase fracture surface area. Moreover, increasing the horizontal stress difference enhances the heat mining rate.
APPLIED THERMAL ENGINEERING
(2022)
Article
Energy & Fuels
Zhanqing Qu, Jiacheng Fan, Tiankui Guo, Xiaoqiang Liu, Jian Hou, Meijia Wang
Summary: A large-size phase change proppant was developed for hydraulic fracturing in marine NGH reservoirs. The emulsification process was optimized to control the particle size and prevent cementation, resulting in cured proppants with regular structure and good compressive strength, and emulsion proppants with good transport capacity.
Article
Energy & Fuels
Mingkun Lv, Zhanqing Qu, Tiankui Guo, Ming Chen, Yuanhang Zhang, Xuliang Jia, Xiaoqiang Liu, Yiwen Liu
Summary: Hydraulic fracturing is crucial for tapping into unconventional oil and gas resources. Understanding the transport characteristics of granular materials such as temporary plugging agents (TPA) and proppants within fractures is essential for optimizing the fracturing process and achieving better results. The study found that using different fracturing fluids and concentrations of floating agents can improve the filling of fractures when injecting different sizes of TPA. Additionally, the use of coated quartz sand enhances its transport capacity and reduces the amount of sand needed. This research has important implications for the effectiveness of hydraulic fracturing operations.
Editorial Material
Engineering, Chemical
Tiankui Guo, Ming Chen
Article
Engineering, Petroleum
Mingkun Lv, Tiankui Guo, Zhanqing Qu, Ming Chen, Caili Dai, Xiaoqiang Liu
Summary: The filling of proppants within complex fractures is crucial for the effectiveness of volumetric fracturing in shale. This study used a visual simulation equipment to analyze the transport of proppants within complex fractures. The experiments showed that factors such as perforation, fluid flow velocity, proppant concentration and size, and injection techniques all affect proppant transport. Additionally, the shape, flow rate, and inclination of the fractures also play a role in proppant transport.
Article
Energy & Fuels
Jia-Cheng Fan, Zhan-Qing Qu, Tian-Kui Guo, Ning Qi, Ming Chen, Jian Hou, Ji-Jiang Ge, Xiao-Qiang Liu, Ji-Wei Wang
Summary: Hydraulic fracturing is critical for the economic development of unconventional oil and gas reservoirs. The performance of proppants plays a key role in fracture propping and reservoir stimulation. Traditional proppants face limitations in migration within deeper reservoirs, highlighting the need for proppants with good transportation capacity and fracture propping effects. A novel self-generated proppant based on toughened low-viscosity and low-density epoxy resin was developed, demonstrating good migration capacity due to the low resin density.
Article
Energy & Fuels
Tian-Kui Guo, Zhi-Lin Luo, Jin Zhou, Yuan-Zhi Gong, Cai-Li Dai, Jin Tang, Yang Yu, Bing Xiao, Bao-Lun Niu, Ji-Jiang Ge
Summary: This study investigates the migration and placement of proppants within complex fractures by considering fracture wall roughness using computational fluid mechanics-discrete element method (CFD-DEM). The results show that proppant placement non-uniformity and migration capacity are enhanced in rough fractures compared to smooth fractures. The injection rate and fracturing fluid viscosity have a significant impact on proppant migration and placement.
Article
Materials Science, Multidisciplinary
Tiankui Guo, Zhilin Luo, Shanbo Mou, Ming Chen, Yuanzhi Gong, Jianhua Qin
Summary: This study investigates the problem of large-scale inclined fractures in unconventional reservoirs using numerical methods, considering the influence of factors such as fracture roughness, inclination, proppant particle size, injection rate, and fluid viscosity. The results show that a rough wall allows the proppant to travel farther and cover larger areas, while the inclination angle has little effect on dunes but significant influence on the suspension zone. In addition, small particle size, high injection rate, and high fluid viscosity are beneficial for proppant transport.
FDMP-FLUID DYNAMICS & MATERIALS PROCESSING
(2022)
Article
Green & Sustainable Science & Technology
Cameron Bracken, Nathalie Voisin, Casey D. Burleyson, Allison M. Campbell, Z. Jason Hou, Daniel Broman
Summary: This study presents a methodology and dataset for examining compound wind and solar energy droughts, as well as the first standardized benchmark of energy droughts across the Continental United States (CONUS) for a 2020 infrastructure. The results show that compound wind and solar droughts have distinct spatial and temporal patterns across the CONUS, and the characteristics of energy droughts are regional. The study also finds that compound high load events occur more often during compound wind and solar droughts than expected.
Article
Green & Sustainable Science & Technology
Ning Zhang, Yanghao Yu, Jiawei Wu, Ershun Du, Shuming Zhang, Jinyu Xiao
Summary: This paper provides insights into the optimal configuration of CSP plants with different penetrations of wind power by proposing an unconstrained optimization model. The results suggest that large solar multiples and TES are preferred in order to maximize profit, especially when combined with high penetrations of wind and photovoltaic plants. Additionally, the study demonstrates the economy and feasibility of installing electric heaters (EH) in CSP plants, which show a linear correlation with the penetration of variable energy resources.
Article
Green & Sustainable Science & Technology
M. Szubel, K. Papis-Fraczek, S. Podlasek
Article
Green & Sustainable Science & Technology
J. Silva, J. C. Goncalves, C. Rocha, J. Vilaca, L. M. Madeira
Summary: This study investigated the methanation of CO2 in biogas and compared two different methanation reactors. The results showed that the cooled reactor without CO2 separation achieved a CO2 conversion rate of 91.8%, while the adiabatic reactors achieved conversion rates of 59.6% and 67.2%, resulting in an overall conversion rate of 93.0%. Economic analysis revealed negative net present worth values, indicating the need for government monetary incentives.
Article
Green & Sustainable Science & Technology
Yang Liu, Yonglan Xi, Xiaomei Ye, Yingpeng Zhang, Chengcheng Wang, Zhaoyan Jia, Chunhui Cao, Ting Han, Jing Du, Xiangping Kong, Zhongbing Chen
Summary: This study investigated the effect of using nanofiber membrane composites containing Prussian blue-like compound nanoparticles (PNPs) to relieve ammonia nitrogen inhibition of rural organic household waste during high-solid anaerobic digestion and increase methane production. The results showed that adding NMCs with 15% PNPs can lower the concentrations of volatile fatty acids and ammonia nitrogen, and increase methane yield.
Article
Green & Sustainable Science & Technology
Zhong Ge, Xiaodong Wang, Jian Li, Jian Xu, Jianbin Xie, Zhiyong Xie, Ruiqu Ma
Summary: This study evaluates the thermodynamic, exergy, and economic performance of a double-stage organic flash cycle (DOFC) using ten eco-friendly hydrofluoroolefins. The influences of key parameters on performance are analyzed, and the advantages of DOFC over single-stage type are quantified.
Article
Green & Sustainable Science & Technology
Nicolas Kirchner-Bossi, Fernando Porte-Agel
Summary: This study investigates the optimization of power density in wind farms and its sensitivity to the available area size. A novel genetic algorithm (PDGA) is introduced to optimize power density and turbine layout. The results show that the PDGA-driven solutions significantly reduce the levelized cost of energy (LCOE) compared to the default layout, and exhibit a convex relationship between area and LCOE or power density.
Article
Green & Sustainable Science & Technology
Chunxiao Zhang, Dongdong Li, Lin Wang, Qingpo Yang, Yutao Guo, Wei Zhang, Chao Shen, Jihong Pu
Summary: In this study, a novel reversible liquid-filled energy-saving window that effectively regulates indoor solar radiation heat gain is proposed. Experimental results show that this window can effectively reduce indoor temperature during both summer and winter seasons, while having minimal impact on indoor illuminance.
Article
Green & Sustainable Science & Technology
Alessandro L. Aguiar, Martinho Marta-Almeida, Mauro Cirano, Janini Pereira, Leticia Cotrim da Cunha
Summary: This study analyzed the Brazilian Equatorial Shelf using a high-resolution ocean model and found significant tidal variations in the area. Several hypothetical barrages were proposed with higher annual power generation than existing barrages. The study also evaluated the installation effort of these barrages.
Article
Green & Sustainable Science & Technology
Francesco Superchi, Nathan Giovannini, Antonis Moustakis, George Pechlivanoglou, Alessandro Bianchini
Summary: This study focuses on the optimization of a hybrid power station on the Tilos island in Greece, aiming to increase energy export and revenue by optimizing energy fluxes. Different scenarios are proposed to examine the impact of different agreements with the grid operator on the optimal solution.
Article
Green & Sustainable Science & Technology
Peimaneh Shirazi, Amirmohammad Behzadi, Pouria Ahmadi, Sasan Sadrizadeh
Summary: This research presents two novel energy production/storage/usage systems to reduce energy consumption and environmental effects in buildings. A biomass-fired model and a solar-driven system integrated with photovoltaic thermal (PVT) panels and a heat pump were designed and assessed. The results indicate that the solar-based system has an acceptable energy cost and the PVT-based system with a heat pump is environmentally superior. The biomass-fired system shows excellent efficiency.
Article
Green & Sustainable Science & Technology
Zihao Qi, Yingling Cai, Yunxiang Cui
Summary: This study aims to investigate the operational characteristics of the solar-ground source heat pump system (SGSHPS) in Shanghai under different operation modes. It concludes that tandem operation mode 1 is the optimal mode for winter operation in terms of energy efficiency.
Article
Green & Sustainable Science & Technology
L. Bartolucci, S. Cordiner, A. Di Carlo, A. Gallifuoco, P. Mele, V. Mulone
Summary: Spent coffee grounds are a valuable biogenic waste that can be used as a source of biofuels and valuable chemicals through pyrolysis and solvent extraction processes. The study found that heavy organic bio-oil derived from coffee grounds can be used as a carbon-rich biofuel, while solvent extraction can extract xantines and p-benzoquinone, which are important chemicals for various industries. The results highlight the promising potential of solvent extraction in improving the economic viability of coffee grounds pyrolysis-based biorefineries.
Article
Green & Sustainable Science & Technology
Luiza de Queiroz Correa, Diego Bagnis, Pedro Rabelo Melo Franco, Esly Ferreira da Costa Junior, Andrea Oliveira Souza da Costa
Summary: Building-integrated photovoltaics, especially organic solar technology, are important for reducing greenhouse gas emissions in the building sector. This study analyzed the performance of organic panels laminated in glass in a vertical installation in Latin America. Results showed that glass lamination and vertical orientation preserved the panels' performance and led to higher energy generation in winter.
Article
Green & Sustainable Science & Technology
Zhipei Hu, Shuo Jiang, Zhigao Sun, Jun Li
Summary: This study proposes innovative fin arrangements to enhance the thermal performance of latent heat storage units. Through optimization of fin distribution and prediction of transient melting behaviors, it is found that fin structures significantly influence heat transfer characteristics and melting behaviors.
