Article
Thermodynamics
Jianxing Liao, Ke Hu, Faisal Mehmood, Bin Xu, Yuhang Teng, Hong Wang, Zhengmeng Hou, Yachen Xie
Summary: In this study, a new THM coupled approach based on embedded discrete fracture networks (DFNs) is proposed for simulating the long-term performance of CO2-EGS. The feasibility of the approach is verified through comparison with analytical solution and other methods. The simulation results show the importance of incorporating the THM coupling effect in high temperature reservoirs, as the thermal stress enhances the fracture width and decreases the injection pressure.
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
Energy & Fuels
Christopher Juhlin, Mikael Erlstrom, Bjorn Lund, Jan-Erik Rosberg
Summary: This study conducted an integrated analysis of reflection seismic data, borehole logs, and seismicity in a geothermal exploratory project in Sweden. It found high fracture frequency and unexpected orientations in the crystalline basement, providing novel insights into the geological characteristics of the area.
Article
Geosciences, Multidisciplinary
G. Taylor, G. Hillers, T. A. T. Vuorinen
Summary: The study estimated vertical rotation rates for induced earthquakes, compared them with translational motion, and found deviations indicating heterogeneous seismic structure. Rotation method resolved site specific variations controlled by local geology, with apparent S wave speeds consistent with high propagation velocities in the study area.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Geochemistry & Geophysics
Hao Guo, Clifford Thurber
Summary: Researchers have developed a double-difference seismic attenuation (DDQ) tomography method for high-resolution imaging of 3-D attenuation structure. By utilizing a new spectral ratio method, they are able to accurately determine attenuation data and achieve higher imaging accuracy and resolution.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
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
Energy & Fuels
Christopher Juhlin, Mikael Erlstrom, Bjorn Lund, Jan-Erik Rosberg
Summary: An integrated study of seismic data, borehole logs, and seismicity analysis was conducted in a geothermal exploration project in Malmo, Sweden. The study revealed that the reflectivity in the basement is likely caused by mafic amphibolite lenses embedded in a felsic gneissic matrix. The high fracture frequency in the crystalline rock mass suggests potential for heat extraction.
Article
Engineering, Geological
Chengzeng Yan, Xin Xie, Yuhang Ren, Wenhui Ke, Gang Wang
Summary: A coupled thermal-hydro-mechanical (THM) model based on the combined finite-discrete element method (FDEM) is proposed for simulating rock cracking driven by multi-physics. By simulating the interaction between thermal, hydraulic, and mechanical processes, the study shows that branching fractures can be produced in addition to the primary fracture during hydraulic fracturing.
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
(2022)
Article
Energy & Fuels
Xufeng Liang, Tao Meng, Gan Feng, Guanghui Zhao, Zhixia Wang, Pengtao Liu
Summary: The self-healing characteristic of salt rock under the coupled thermo-hydro-mechanical (THM) environment is important for the safety assessment of underground repositories. Through treatment with self-designed high-temperature and high-pressure THM coupled equipment, the evolution of permeability and pore structure of salt rock and its self-healing mechanism are studied. The results show that the healing effect is best in the temperature range of 400-500 degrees C, and the overall microscopic parameters decrease when the temperature is 400-500 degrees C.
JOURNAL OF ENERGY STORAGE
(2023)
Article
Geochemistry & Geophysics
Dong Yan, You Tian, Dapeng Zhao, Hongli Li
Summary: A high-precision earthquake catalog was created using continuous waveform data recorded at 360 portable seismographs deployed in the Changbaishan-Tianchi volcanic area. The study revealed the 3-D structures of the crust beneath the study region and identified a high-Vp/Vs zone accompanied by volcanic earthquakes, indicating the presence of a magma chamber. The findings suggest a multilevel structure of magma chambers in the upper and middle crust, which is closely associated with the diverse eruption styles of the Changbaishan volcano.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Geochemistry & Geophysics
Guoqing Lin, Zhigang Peng, Miguel Neves
Summary: This study presents estimations and comparisons of in situ V-p/V-s ratios and seismicity characteristics for the Parkfield segment of the San Andreas fault in northern California and the San Jacinto Fault Zone and its adjacent regions in southern California. The high-resolution in situ V-p/V-s ratios are found to be more complex than the tomographic V-p/V-s models and are influenced by material properties and fluid contents. The study also observes velocity contrasts between different fault sections and anomalous V-p/V-s variation patterns in southern California. The correlation between similar events and anomalous V-p/V-s ratios supports the role of fluids in repeating earthquakes.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Geochemistry & Geophysics
Hao Guo, Clifford Thurber
Summary: Water injection and Enhanced Geothermal System (EGS) technologies are important for exploiting heat resources from geothermal reservoirs. This study focuses on monitoring spatial and temporal changes in the physical properties of a geothermal field in California. The high-resolution models generated from the seismic data reveal that the different reservoirs in the geothermal field exhibit distinct seismic responses to water injection, which can be attributed to their geological properties and the induced changes in fracturing and saturation. The results suggest that the presence of high-permeability zones and pre-existing permeable fault zones are crucial for the success of EGS in this geothermal system.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2022)
Article
Geochemistry & Geophysics
Can Oren, Jeffrey Shragge
Summary: The study proposes a methodology for microseismic image-domain wavefield tomography using the elastic wave equation and zero-lag and extended source images to improve the accuracy of elastic velocity models and event location precision.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Energy & Fuels
Hannes Hofmann, Guenter Zimmermann, Ernst Huenges, Simona Regenspurg, Santiago Aldaz, Claus Milkereit, Sebastian Heimann, Torsten Dahm, Arno Zang, Francesco Grigoli, Dimitrios Karvounis, Marco Broccardo, Stefan Wiemer, Vala Hjorleifsdottir, Bjarni Reyr Kristjansson, Gylfi Pall Hersir, Ragnheidur St Asgeirsdottir, Rognvaldur Magnusson, Sigurveig Arnadottir
Summary: Reykjavik is heated by geothermal energy, but recent city growth increased heat demand. Soft stimulation concepts were developed to improve geothermal well performance, with successful demonstration in a hydraulic soft stimulation project in 2019.
Article
Geosciences, Multidisciplinary
F. Napolitano, O. Amoroso, V. De Novellis, G. M. Adinolfi, R. De Matteis, E. Sansosti, D. Russo, R. Caputo, V. Convertito
Summary: We used 3D seismic tomography to image the crustal volume affected by the March-April 2021 Thessaly sequence. The results reveal blind fluid-filled inherited structures and a basal detachment accommodating the Pelagonian nappe onto the carbonate of the Gavrovo unit. The high V-P/V-S ratios in the northwest edge of the seismogenic volume suggest possible fluid accumulation that contributed to the evolution of the sequence, and additional faults parallel and antithetical to the main structures were identified for future seismic risk mitigation.
FRONTIERS IN EARTH SCIENCE
(2023)
Article
Energy & Fuels
Yingqi Zhang, Curtis M. Oldenburg, Quanlin Zhou, Lehua Pan, Barry M. Freifeld, Pierre Jeanne, Veronica Rodriguez Tribaldos, Donald W. Vasco
Summary: Ensuring the safety and integrity of underground gas storage (UGS) infrastructure is crucial for energy reliability in California and worldwide. The Integrated Risk Management and Decision Support System (IRMDSS) combines advanced monitoring and simulation technologies to provide real-time data and simulation tools to UGS operators, alerting them to potential failures, detecting early leakage, and supporting mitigation decision-making to prevent larger failures. The system can analyze temperature and pressure responses to hypothetical leaks, identify gas-water-contact depth, provide early warning signals, estimate leak rates, and support mitigation decisions.
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2022)
Article
Engineering, Environmental
Alborz Fathinezhad, Navid H. Jafari, Curtis M. Oldenburg, Michael D. Caldwell
Summary: Air intrusion into a landfill can cause a switch from anaerobic to aerobic conditions, leading to a temperature increase and changes in gas composition. The magnitude of these effects depends on the air flow rate and the location of the intrusion point.
Article
Geosciences, Multidisciplinary
Michael Commer, David L. Alumbaugh, G. Michael Hoversten, Evan S. Um, Donald W. Vasco, Michael Wilt, Edward Nichols, Pierpaolo Marchesini, Marie Macquet
Summary: In geophysical inversions, lower and upper model parameter bounds play an important role in stabilizing the solution. Reliable prior information is crucial in constructing these bound constraints. It is common practice to narrow or widen these bounds based on the certainty of the prior information. However, this study explores the use of wider bounds in poorly resolved zones to enhance the potential for resolving hidden anomalies. Results from synthetic and field data inversions demonstrate the effectiveness of this approach in detecting non-horizontal structures.
FRONTIERS IN EARTH SCIENCE
(2022)
Article
Geochemistry & Geophysics
Jonathan Ajo-Franklin, Veronica Rodriguez Tribaldos, Avinash Nayak, Feng Cheng, Robert Mellors, Benxin Chi, Todd Wood, Michelle Robertson, Cody Rotermund, Eric Matzel, Dennise C. Templeton, Christina Morency, Kesheng Wu, Bin Dong, Patrick Dobson
Summary: This report describes a large-scale distributed acoustic sensing (DAS) recording study in the Imperial Valley, aiming to evaluate DAS as a tool for geothermal exploration and monitoring. The study utilizes a 27 km array to acquire high-density seismic data and record local seismic events and ambient noise. The report provides installation information, noise characteristics, and metadata for future research.
SEISMOLOGICAL RESEARCH LETTERS
(2022)
Article
Engineering, Geological
Xuhai Tang, Yiheng Zhang, Jingjing Xu, Jonny Rutqvist, Mengsu Hu, Zhengzhi Wang, Quansheng Liu
Summary: Scientists have developed a new method, using microscale rock mechanics experiments (micro-RME) results, to determine the macroscale mechanical properties of arbitrarily shaped granite. This method has been proven to be a breakthrough from the conventional technology of macro-RME by using test specimens from small and arbitrarily shaped rock fragments.
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
(2022)
Article
Engineering, Geological
Tsubasa Sasaki, Jonny Rutqvist
Summary: Safety assessment of geological nuclear waste repositories is essential. This study investigates the effect of time-dependent deformation of shale on the long-term integrity of a generic subsurface nuclear waste repository. Results suggest potential advantages of constructing repositories in high creep shale.
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
(2022)
Article
Computer Science, Interdisciplinary Applications
H. Tounsi, J. Rutqvist, M. Hu, R. Wolters
Summary: This study analyses the flow of brine in rock salt using a fully coupled THM model that considers non-isothermal two-phase flow through deformable porous media. The experimental data and model predictions show good agreement, and suggest that it is important to consider the coupling between heating-and cooling-induced damage and flow properties to estimate brine inflow accurately. This modeling approach will be helpful for designing the cooling phase in salt repositories to minimize damage and brine inflow.
COMPUTERS AND GEOTECHNICS
(2023)
Article
Geosciences, Multidisciplinary
I. R. Kivi, R. Y. Makhnenko, C. M. Oldenburg, J. Rutqvist, V. Vilarrasa
Summary: This study develops a computationally efficient transport model to investigate the dynamic process of the basin-wide upward migration of CO2 in a multi-layered geological environment. The results show that significant leaks of CO2 are unlikely to occur, ensuring the security of underground storage.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Energy & Fuels
Carmen Winn, Patrick Dobson, Craig Ulrich, Timothy Kneafsey, Thomas S. Lowry, John Akerley, Ben Delwiche, Abraham Samuel, Stephen Bauer
Summary: Lost circulation is a common and costly problem in geothermal energy development, accounting for up to 30% of drilling costs. The occurrence of lost circulation is often associated with fault intersections, and fields with heavy faulting show secondary mineralization near the lost circulation areas. Mitigation strategies include using locally available materials, proprietary lost circulation materials, cement plugs, and drilling blind with aerated, polymer-based mud. However, the choice of mitigation method depends on the severity and location of lost circulation events and the availability of materials.
Article
Geochemistry & Geophysics
J. J. Xu, Y. H. Zhang, J. Rutqvist, M. S. Hu, Z. Z. Wang, X. H. Tang
Summary: Understanding the thermal effects on rock is critical for geothermal resource exploration and understanding Earth's temperature-driven evolution. This study observed the thermal-induced microcrack propagation of granite in real time using an ultrahigh-temperature instrument on an optical microscope. The experimental results revealed that microcracks initiate at 300°C and coalesce between 400 and 600°C, which is the main reason for the sharp decrease in macroscale mechanical properties of granite.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Thermodynamics
Allan Katende, Jonny Rutqvist, Cody Massion, Mileva Radonjic
Summary: Global energy systems are transitioning to clean energy sources to reduce carbon dioxide emissions, necessitating the exploration and development of shale gas resources to support the global supply of natural gas. The challenge lies in the low permeability of shale, requiring large-scale volume fracturing to enhance connectivity. This study investigates the influence of a thin proppant layer on a single fracture and explores the effects of rock mineralogy, surface roughness, fluids, confining stress, time, temperature, and bedding on proppant embedment in Caney shale. The experiment revealed that fracture conductivity is primarily affected by proppant layer, roughness, mineralogy, fluids, temperature, and closure stress.
Article
Energy & Fuels
Allan Katende, Connor Allen, Jonny Rutqvist, Seiji Nakagawa, Mileva Radonjic
Summary: The current global energy supply is insufficient to meet the increasing demand, resulting in soaring energy prices. Shale oil and gas, although non-renewable, are relatively clean energy resources and still dominate the energy market. This paper investigates the stress-dependent changes in hydraulic conductivity and mechanical fracture-proppant interactions in Caney Shale, finding that proppant size is crucial for improving fracture conductivity.
Article
Green & Sustainable Science & Technology
Mark Bolinger, Dev Millstein, Will Gorman, Patrick Dobson, Seongeun Jeong
Summary: Studies indicate that a diverse mix of zero-carbon resources, including geothermal energy, will be crucial for decarbonizing the U.S. electricity sector. However, geothermal deployment has been slow compared to wind, solar, and storage due to its historically lower net value. Although the market value of geothermal may improve in the future, it is unlikely to overcome the cost gap with other, lower-cost resources, which calls for policy intervention and continued research and development investments to sustain the geothermal industry.
Article
Engineering, Geological
Hafssa Tounsi, Jonny Rutqvist, Mengsu Hu, Ralf Wolters, Svetlana Lerche
Summary: Rock salt is a potential host for heat generating nuclear waste due to its self-sealing capacity, low permeability, and high thermal conductivity. The geologic disposal of larger-sized canisters originally designed for spent fuel storage and transportation is being considered as a cost-effective alternative; however, their long-term vertical movement and low-stress creep behavior need to be evaluated. Different creep models were compared and the results showed that models calibrated only against high-deviatoric stress data might lead to inaccurate estimations of canister movement in salt formations.
Article
Geochemistry & Geophysics
Feng Cheng, Jonathan B. Ajo-Franklin, Avinash Nayak, Veronica Rodriguez Tribaldos, Robert Mellors, Patrick Dobson
Summary: We utilize distributed acoustic sensing (DAS) and ambient noise interferometry to image the geothermal reservoirs in Imperial Valley, California, using unlit fiber-optic telecommunication infrastructure (dark fiber). By applying ambient noise interferometry to DAS records, we obtain a high-resolution two-dimensional (2D) S wave velocity (V-s) structure to a depth of 3 km. We discover a high V-s and low V-p/V-s ratio feature beneath the Brawley geothermal system, indicating hydrothermal mineralization and lower porosity.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(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.
