Article
Energy & Fuels
Ilmo T. Kukkonen, Pekka J. Heikkinen, Peter E. Malin, Joerg Renner, Georg Dresen, Aino Karjalainen, Jussi Rytkonen, Juha Solantie
Summary: In this study, hydraulic stimulation data from the St1 Deep Heat Project in southern Finland were analyzed to evaluate the conditions for an Enhanced Geothermal System. The results show that hydraulic conductivity in the soil is pressure-dependent, heterogeneously distributed, and affected by fractures and lithological variation. Although stimulation temporarily increased conductivity, it gradually returned to the natural level after pressure release. The project provided valuable experience and data on deep drilling, hydrogeological properties, and seismic response to stimulation of crystalline rock.
Article
Environmental Sciences
Sandro Andres, David Santillan, Juan Carlos Mosquera, Luis Cueto-Felgueroso
Summary: Enhanced Geothermal Systems (EGS) can promote sustainable development by providing a green energy supply. However, hydraulic stimulation is often required to improve fluid flow and energy efficiency. This study uses numerical simulations to evaluate the seismic risk associated with hydraulic stimulation and finds that it is not only related to induced seismicity but can also cause a decline in reservoir temperature.
Article
Geosciences, Multidisciplinary
Chen Zubin, Zhao Fa, Sun Feng, Lu Hao, Wang Chunlu, Wu Haidong, Zhou Xiaohua
Summary: The study analyzed a hydraulic stimulation experiment on hot dry rock in China and found that large-magnitude microseismic events increased with the total fluid volume, while the stimulation experiment induced small amounts of seismic activity. The forecasted magnitudes of events can guide operational decisions regarding induced seismicity during hydraulic fracturing operations, providing a basis for risk assessment of hot dry rock exploitation.
ACTA GEOLOGICA SINICA-ENGLISH EDITION
(2021)
Article
Geosciences, Multidisciplinary
Ziyan Li, Derek Elsworth, Chaoyi Wang
Summary: In this study, a hybrid machine learning model was developed to accurately predict the evolution of permeability during hydraulic stimulation experiments. The model combines a machine learning model trained on historical data and a physics-inspired model to estimate permeability.
FRONTIERS IN EARTH SCIENCE
(2022)
Article
Green & Sustainable Science & Technology
Jasmin Grifka, Mathias Nehler, Tobias Licha, Thomas Heinze
Summary: Fines material can compromise the permeability of geothermal reservoirs, and this study investigates the generation of fines due to dissolution and its dependence on reaction conditions. The results show that fines greatly reduce the permeability of rock samples.
Review
Energy & Fuels
Yunzhong Jia, Chin-Fu Tsang, Axel Hammar, Auli Niemi
Summary: This paper reviews hydraulic stimulation strategies for enhanced geothermal systems (EGS), including the mechanisms of permeability and heat exchange area increases, as well as fluid injection-induced seismicity. Different hydraulic stimulation strategies, such as conventional hydraulic stimulation, multi-stage fracturing, and cyclic soft stimulation, are discussed based on theoretical studies, laboratory experiments, and in-situ field experiments. The importance of a comprehensive geological characterization, proper well arrangement design, and appropriate fluid injection strategy for successful EGS development is emphasized.
GEOMECHANICS AND GEOPHYSICS FOR GEO-ENERGY AND GEO-RESOURCES
(2022)
Article
Energy & Fuels
Kc Bijay, Ehsan Ghazanfari
Summary: The study found that hydro-shearing in EGS leads to permanent shear slip in fractures, significantly enhancing permeability. Thermal stress at elevated temperatures could also contribute to mechanical crushing of asperities and weak fractures, resulting in more gouge particles.
Article
Engineering, Geological
Wei Wu, Marco Calo, Zhou Fang
Summary: Understanding the mechanism of injection-induced seismicity is crucial for managing geothermal energy development. This study reanalyzed seismic data from acid fluid and water injection experiments, revealing that acid treatment promotes the number of induced seismic events, while water injection expands their distribution. Experimental evidence showed non-linear distributions of water pressure and frictional strength during water injection, with a decrease in the ratio of shear stress variation to fluid pressure variation as the slip front amplification factor increases. Additionally, acid treatment may increase the number of seismic events but decrease their moment magnitude.
ENGINEERING GEOLOGY
(2022)
Article
Geochemistry & Geophysics
Taeho Kim, Jean-Philippe Avouac
Summary: Induced seismicity during Enhanced Geothermal Stimulation in Otaniemi, Finland was modeled using statistical and physical approaches. The physical model, assuming rate-and-state friction, produced simulations closest to the observations, highlighting the importance of a time-dependent earthquake nucleation process in reproducing the spatial pattern of seismicity. A statistical model, estimating seismicity rate based on convolution of the injection history with a kernel approximating earthquake triggering by fluid diffusion, also fit the observations well and had superior computational efficiency. The Kaiser effect, however, was not clearly observed in the data from Otaniemi.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Energy & Fuels
Gang Hui, Zhang-Xin Chen, Hai Wang, Zhao-Jie Song, Shu-Hua Wang, Hong-Liang Zhang, Dong-Mei Zhang, Fei Gu
Summary: This study collects a comprehensive dataset from 594 fracturing wells in the Duvernay Formation near Fox Creek, Alberta, to quantify the influences of various factors on hydraulic fracturing-induced seismicity. Through an integrated machine learning investigation, the study identifies significant predictors and successfully guides fracturing job size to reduce seismicity risks. The findings contribute to mitigating potential seismicity risks in other seismicity frequent regions.
Article
Geochemistry & Geophysics
Rong Zhao, Jing Xue, Kai Deng
Summary: Abnormal seismic activities near reservoirs are strongly correlated with the water filling history. These seismic activities are caused by changes in crustal pore pressure and stress due to water impounded behind the dams. This study presents a numerical investigation of the seismicity rate evolution of reservoir-induced earthquakes using a fully coupled 2-D poroelastic model. The results show that shallow earthquakes are mainly caused by pore pressure increase, while poroelastic stress transfer dominates at depth. The temporal evolution of reservoir-induced earthquakes is primarily controlled by tectonic environment.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
Article
Energy & Fuels
Ke Xu, Hui Zhang, Zhizhen Zhang, Guoqing Yin, Xiaoji Shang, Zhimin Wang, Haiying Wang, Fang Yuan, Ziwei Qian, Shujun Lai
Summary: This paper investigates the coupling effect of in situ stress and fluid pore pressure during hydraulic fracturing and gas fracturing in heterogeneous fractured reservoirs. A coupled fluid-solid-damage mathematical model is established and numerical simulations are conducted. The results show that continuous injection of nitrogen or water increases pore pressure and leads to rock damage and increased porosity. The damage area and length for nitrogen fracturing are larger than hydraulic fracturing, and the changes in pore pressure, permeability, and porosity are consistent with the damage area. The damage evolution during nitrogen fracturing is less affected by in situ stress and matrix permeability compared to hydraulic fracturing.
ENERGY SCIENCE & ENGINEERING
(2023)
Article
Energy & Fuels
Hwajung Yoo, Sehyeok Park, Linmao Xie, Kwang-Il Kim, Ki-Bok Min, Jonny Rutqvist, Antonio Pio Rinaldi
Summary: This study presents comprehensive coupled hydro-mechanical numerical modeling of the first and second hydraulic stimulations at the Pohang enhanced geothermal system (EGS) site. The key hydro-mechanical processes of shear slip and dilation and hydraulic jacking observed in the fractured reservoir can be successfully reproduced through numerical modeling.
Article
Thermodynamics
Xiaochu Wang, Youhong Sun, Bing Li, Guobiao Zhang, Wei Guo, Shengli Li, Shuhui Jiang, Saiyu Peng, Hangkai Chen
Summary: Low production rate, limited recovery range, and short period of stabilized production in NGH field trials indicate a large gap to commercial production. Reservoir stimulation methods such as hydraulic fracturing, jet breaking, overlying layer modification, and split grouting have been studied to improve gas recovery efficiency. Split grouting is the most promising method for both reservoir skeleton reinforcement and permeability enhancement. Further evaluations are needed for production enhancement in non-diagenetic hydrate reservoirs considering the evolution of artificial seepage channels. Future developments should focus on obtaining reliable results of NGH reservoir fracability, bridging the gap between concept design and practical application, and ensuring safe and efficient gas production through reservoir stimulation and stability.
Article
Engineering, Geological
Takuya Ishibashi, Hiroshi Asanuma, Yusuke Mukuhira, Noriaki Watanabe
Summary: To accurately predict fracture network structures and energy extraction in enhanced geothermal systems (EGS), we investigate the hydraulic shear process and its linkage with mechanical properties of granite fractures. Our experiments reveal that granite fracture permeability increases even at high effective normal stress, and the increase is proportional to shear slip and stress drop. We also observe that hydraulic shear does not significantly alter the surface characteristics of fractures. Combining experimental results with seismological analysis, we propose an energy balance model for hydraulic shearing and derive a constitutive model related to permeability change in granite fractures. We also investigate the formation of preferential flow paths within fractures during hydraulic shearing and their impact on fracture permeability improvement. Our study provides new insights into hydro-mechanical coupled processes in hydraulic shearing and improves the accuracy of fracture network design in EGS technology.
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
(2023)
Article
Engineering, Ocean
Chenpeng Song, Derek Elsworth, Sheng Zhi, Chaoyi Wang
Summary: Sporosarcina pasteurii (ATCC 11859) is a nitrogen-circulating bacterium capable of precipitating calcium carbonate, which can be applied in strengthening coastal foundations and preventing erosion. Research shows that particle morphology plays a critical role in microbially induced clogging mechanisms, with spherical particles having higher calcium carbonate content and angular particles leading to more effective permeability reduction.
MARINE GEORESOURCES & GEOTECHNOLOGY
(2021)
Article
Engineering, Geological
Sheng-Qi Yang, Wen-Ling Tian, Derek Elsworth, Jian-Guo Wang, Li-Feng Fan
ROCK MECHANICS AND ROCK ENGINEERING
(2020)
Article
Geochemistry & Geophysics
Mengke An, Fengshou Zhang, Derek Elsworth, Zhengyu Xu, Zhaowei Chen, Lianyang Zhang
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2020)
Article
Geochemistry & Geophysics
Mengke An, Fengshou Zhang, Zhaowei Chen, Derek Elsworth, Lianyang Zhang
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2020)
Article
Geochemistry & Geophysics
Zhiqiang Chen, Derek Elsworth, Moran Wang
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2020)
Article
Engineering, Geological
Adam K. Schwartzkopff, Atsushi Sainoki, Derek Elsworth
Summary: The study found that using the X-FEM method can efficiently predict fault mechanics due to fluid injection, demonstrating the accuracy and applicability of this approach in simulating fault mechanics.
ROCK MECHANICS AND ROCK ENGINEERING
(2021)
Article
Geosciences, Multidisciplinary
Mengke An, Fengshou Zhang, Ki-Bok Min, Derek Elsworth, Chris Marone, Changrong He
Summary: Research indicates that metamorphic minerals such as epidote and chlorite can influence the stability of faults in geothermal reservoirs, affecting frictional behavior and potentially leading to seismic activity. The presence of these minerals in fault gouges can destabilize slip and induce earthquakes, while also revealing a dependence of fault strength and stability on fault zone composition. Understanding the impact of these minerals on fault behavior is crucial for assessing earthquake triggering potential in geothermal systems.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Geosciences, Multidisciplinary
J. B. Zhu, J. Q. Kang, D. Elsworth, H. P. Xie, Y. Ju, J. Zhao
Summary: The study shows that cyclic fluid injection can reduce the magnitude and total energy of induced earthquakes, providing a way to potentially control the size of induced seismic events.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Energy & Fuels
Jianwei Tian, Jishan Liu, Derek Elsworth, Yee-Kwong Leong, Wai Li, Jie Zeng
Summary: Researchers characterized the structural heterogeneity of hydrofractured shale reservoirs at different hierarchical levels, including nanopore structure, micro-structure, natural fracture networks, and hydraulic fractures. The study demonstrated significant impacts of these heterogeneities on gas production.
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2022)
Article
Energy & Fuels
Junqiang Kang, Derek Elsworth, Xuehai Fu, Shun Liang, Hao Chen
Summary: This study analyzed the impact of water saturation on the permeability of coal reservoirs through experiments and finite element methods, finding that changes in E and v can lead to a faster or slower decrease in permeability, with E having a more significant effect on permeability.
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2022)
Article
Geochemistry & Geophysics
Clay E. Wood, Parisa Shokouhi, Prabhakaran Manogharan, Jacques Rivere, Derek Elsworth, Chris Marone
Summary: The laboratory experiments investigated the relationship between nonlinear elasticity and permeability evolution in fractured media under local stress perturbations. The experiments, conducted with Westerly granite samples, revealed that oscillations of normal stress and pore pressure resulted in transient softening, acoustic velocity fluctuations, and changes in permeability. Alterations in fracture properties due to shearing decreased measured elastic nonlinearity and permeability change for stress and pressure oscillations.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Geochemistry & Geophysics
Mengke An, Fengshou Zhang, Ki-Bok Min, Derek Elsworth, Changrong He, Luanxiao Zhao
Summary: This study investigates the impact of heterogeneity and contiguity of epidote-patch structure on frictional instability and finds that the mode of epidote precipitation controls the response of mixed gouges. The presence of epidote coatings on fractures/faults can enhance velocity-weakening behavior, supporting the potential seismic reactivation of faults.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2022)
Article
Geochemistry & Geophysics
X. Sun, Y. Yao, D. Liu, D. Elsworth
Summary: This study investigates the mechanisms and relationships between CO2 adsorption and coal wettability by combining direct measurements and molecular dynamic simulations. The researchers find that coal wettability significantly weakens under increasing CO2 pressure. This study provides a robust method and results for accurately predicting CO2 storage capacity in coalbeds and enhanced methane recovery.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2022)
Article
Geochemistry & Geophysics
Fengshou Zhang, Rui Huang, Mengke An, Ki-Bok Min, Derek Elsworth, Hannes Hofmann, Xiaoguang Wang
Summary: Experiments on simulated granite fault gouges suggest that fluid injection can induce earthquakes, and variations in effective stress and mineral composition are important factors affecting fault strength and stability.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2022)
Article
Geochemistry & Geophysics
Peng Dong, Rong Chen, Kaiwen Xia, Wei Yao, Zhigang Peng, Derek Elsworth
Summary: This study investigates dynamically triggered earthquakes on laboratory faults and reveals that the triggering process has two distinct phases, with a slow phase only present for a specific seismic condition and absent for supershear events.
SEISMOLOGICAL RESEARCH LETTERS
(2023)
Article
Energy & Fuels
Luis Salala, Jonathan Argueta, Noel Lopez, Osmany Aparicio, Diana Martinez, Pedro Santos, Arturo Quezada, Oziel Garcia, Jose Erazo, Hiroyuki Yamagishi, Noriyoshi Tsuchiya
Summary: Geothermal systems have significant potential to replace reliance on fossil fuels. El Salvador, being tectonically active, already supplies a significant portion of its electricity demand using volcanic geothermal fields. The study compares different geothermal areas in El Salvador and highlights the controlling factors in the characteristics of geothermal reservoirs.
Article
Energy & Fuels
Lin Jia, Kewen Li, Yun Han, Chi Zhang, Lipeng Zhao
Summary: This study proposes a new approach of retrofitting abandoned oil wells into geothermal wells, and investigates the effects of different parameters on the performance using a numerical model. The results show that the enhanced fracture system significantly improves the efficiency of geothermal energy extraction, and optimal design should control the flow rate and use proppant.
Article
Energy & Fuels
K. H. Kvalsvik, H. Holmberg, R. K. Ramstad, K. Midttomme
Summary: This study proposes a new analytical equation that takes into account the advective heat in fractured rock, improving the accuracy of measuring thermal properties in borehole heat exchangers. The equation is applicable to all thermal response tests and provides a cost-effective alternative to numerical modelling.
Article
Energy & Fuels
Ronald Dipippo
Summary: This paper presents a technique of further preheating the working fluid in geothermal binary plants using extraction turbines, and evaluates the performance at various geofluid temperatures through working equations. The results indicate that this approach can be equally effective in geothermal binary plants as it is in conventional nuclear power plants.
Article
Energy & Fuels
Y. A. Popov, E. M. Chekhonin, E. G. Savelev, D. A. Ostrizhniy, A. B. Shakirov, R. A. Romushkevich, E. A. Babich, B. E. Andreyev, M. Y. Spasennykh, I. A. Sannikova
Summary: This paper describes the results of experimental geothermal studies on the formation surrounding the Savitskaya-300 well in the Volga-Ural oil and gas basin. The study found high thermal heterogeneity and anisotropy in the formation. The paper provides important data on thermal properties and heat flow variations in the well.
Article
Energy & Fuels
Viren Thakore, Hong Wang, Jy-An Wang, Yarom Polsky, Fei Ren
Summary: This paper focuses on the stability of foam-based fracturing fluid under high temperature and high pressure conditions. It is of significant importance for the development of foam fracturing fluid as an alternative to conventional water-based fracturing fluid in Enhanced Geothermal System (EGS). Experimental results show that with the appropriate selection of surfactants and stabilizing agents, stable foams can be obtained. Analytical models are developed to predict the foam stability for different foam compositions, considering the effects of temperature and pressure.
Article
Energy & Fuels
Hong Chang, Sheng Jiang, Haozhi Jiang, Yunjie Li, Zhengheng Gan, Songying Zhao
Summary: This study compared the bearing performance between phase change energy piles (GPEP) and traditional energy piles (TEP) using indoor modeling tests and theoretical formulas. The results showed that GPEP increased the ultimate bearing capacity of a single pile by about 13% compared to TEP. Additionally, the phase change materials effectively restricted the temperature-drag response of energy piles.
Article
Energy & Fuels
Qiang Zhang, Tiago Alves
Summary: This study investigates the influence of salt structures and faults on the geothermal potential in the Cleaver Bank High, Southern North Sea, using high-quality 3D seismic reflection data and bottom-hole temperature data. The results show that salt structures and faults play a significant role in the geothermal gradient, with higher gradients found on the footwalls of faults. Three potential geothermal exploration targets are identified based on the findings.
Article
Energy & Fuels
Hubert Langevin, Nicolo Giordano, Jasmin Raymond, Louis Gosselin, Martin Bourbonnais
Summary: This study evaluates the efficiency and cost of solar-assisted geothermal systems in a subarctic climate, and offers recommendations for optimizing ground heat exchanger configurations.
Article
Energy & Fuels
Lei Chen, Jinchuan Zhang, Longfei Xu, Shijing Chen, Qianchao Li, Yuhang Sun, Jie Li, Xingxu Zhao
Summary: This study assesses the geothermal water circulation process of a granite geothermal system in the Lancang area, Yunnan using water chemistry and isotope analysis techniques. The results show that the geothermal water originates from atmospheric precipitation and the granite pluton serves as the main heat source. Additionally, the fault system plays an important role in the discharge and mixing of hot and cold water.
Review
Energy & Fuels
Md Azhar, Somenath Mondal, Anh Minh Tang, Akhileshwar K. Singh
Summary: Contemporary geotechnical engineering practice involves the design and construction of structures that encounter thermal cycles. Understanding the effect of temperature on soil mechanical properties is challenging, but there have been significant contributions from numerous studies. However, to date, there is no comprehensive review that provides a holistic development of the subject and its connection to field applications.
Article
Energy & Fuels
Mark White, Yaroslav Vasyliv, Koenraad Beckers, Mario Martinez, Paolo Balestra, Carlo Parisi, Chad Augustine, Gabriela Bran-Anleu, Roland Horne, Laura Pauley, Giorgia Bettin, Theron Marshall, Anastasia Bernat
Summary: The study presents a comprehensive numerical modeling of closed-loop geothermal systems (CLGSs) and develops a publicly accessible web application for feasibility studies. The results suggest that competitive levelized cost of heat (LCOH) can be achieved, but significant reductions in drilling costs are required to achieve competitive levelized cost of electricity (LCOE). A site-based case study for multi-lateral systems and the analysis of permeable wet rock are also provided, indicating the potential for improved power production with higher reservoir permeability and temperature.
Article
Energy & Fuels
Xiaoming Tian, Oleg Volkov, Denis Voskov
Summary: In this study, an efficient and flexible adjoint-based framework is proposed for history matching and forecasting geothermal energy extraction. The framework reduces the parameter space using Principal Component Analysis and speeds up the iteration process using the adjoint method. Operator-based linearization is used for efficient calculation and matrix assembly. The framework is demonstrated to be highly efficient for a heterogeneous reservoir with multiple realizations, generating reliable history-matching results.
Article
Energy & Fuels
Asrillah Asrillah, Agus Abdullah, Klaus Bauer, Ben Norden, Charlotte M. Krawczyk
Summary: At the Gross Scho center dot nebeck geothermal research platform in the NE German Basin, the degree and direction of azimuthal velocity anisotropy caused by sub-vertical fracturing were determined through analysis of 3-D seismic reflection data. The observed anisotropy above the Zechstein salt roughly correlates to fault structures formed by an upwelling salt pillow, while below the salt, the less pronounced anisotropy and interpreted fracturing follow the trend of the regional stress field.
Article
Energy & Fuels
Kyosuke Okamoto, Yusuke Mukuhira, Dian Darisma, Hiroshi Asanuma, Hirokazu Moriya
Summary: Microseismic monitoring is crucial in geothermal development, and manual phase picking for seismic data is time-consuming. Existing deep learning phase pickers may face challenges in geothermal fields due to their unique features. This study focuses on developing a specialized deep learning model for local seismic networks in geothermal fields, allowing automatic hypocenter determinations and revealing subsurface fine structures.