Geothermics最新文献

{"title":"Terrestrial heat flow and lithospheric thermal structure of Gaoyang low uplift in Jizhong depression, North China","authors":"Feng Liu ,&nbsp;Wei Zhang ,&nbsp;Feng Chen ,&nbsp;Chen Yue ,&nbsp;Linxiao Xing ,&nbsp;Long Li","doi":"10.1016/j.geothermics.2025.103352","DOIUrl":"10.1016/j.geothermics.2025.103352","url":null,"abstract":"<div><div>Gaoyang Low Uplift, situated in Jizhong Depression's central region, is a key geothermal zone in the North China Plain yet remains under-researched regarding its geothermal characteristics. This study selects it as a model area, probing into the ground heat flow and lithospheric thermal structure of its southern and northern parts via geothermal logging and rock-sample tests. By integrating regional tectonic evolution and stratigraphic and structural distribution, the study highlights the significance of various parameters in understanding the lithospheric thermal structure for geothermal resource development in the area. The advantageous geothermal conditions in the northern region stem from several factors: higher mantle heat flow and higher deep temperatures, a thinner lithosphere, shallowly buried carbonate geothermal reservoirs, and extensive extensional water-conducting faults within the Cenozoic strata. Here, mantle heat flow is the key driver of geothermal resources formation. By influencing the strength of geological activity, it in turn affects the other factors.</div></div>","PeriodicalId":55095,"journal":{"name":"Geothermics","volume":"131 ","pages":"Article 103352"},"PeriodicalIF":3.5,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143906505","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unlocking geothermal potential: Activating calcite-filled veins using chelating agents to improve granitic rock permeability","authors":"Lena Muhl ,&nbsp;Luis Salalá ,&nbsp;Eko Pramudyo ,&nbsp;Jiajie Wang ,&nbsp;Ingo Sass ,&nbsp;Noriaki Watanabe","doi":"10.1016/j.geothermics.2025.103356","DOIUrl":"10.1016/j.geothermics.2025.103356","url":null,"abstract":"<div><div>Chemical stimulation of geothermal reservoirs using environmentally friendly chelating agents has emerged as a promising method to complement hydraulic stimulation. While hydraulic techniques have been the primary approach for enhancing permeability, numerous basement rock types worldwide contain infilled veins with calcium-bearing minerals (e.g., calcite) that present a significant opportunity for achieving higher permeability improvements through chemical methods. In this study, flooding experiments were performed on fractured granitic rocks with calcite-filled veins at 200 °C using a 20 wt.% <em>N,N</em>-bis(carboxymethyl)-<em><span>L</span></em>-glutamic acid (GLDA) solution at a pH of 4. The GLDA solution selectively dissolved calcite, reactivating mineral-filled veins, which provided superior fluid-flow pathways compared to the initial artificial fractures. Reactivated veins resulted in dramatic permeability enhancements, reaching up to three orders of magnitude within two hours of stimulation. These results demonstrate the feasibility and effectiveness of chelating agents-assisted chemical stimulation by activating calcite-filling veins.</div></div>","PeriodicalId":55095,"journal":{"name":"Geothermics","volume":"131 ","pages":"Article 103356"},"PeriodicalIF":3.5,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143906506","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geophysical characterization of the Cerro Machin geothermal area using three dimensional seismic and resistivity models","authors":"Juan Herrera ,&nbsp;Marco Calò","doi":"10.1016/j.geothermics.2025.103370","DOIUrl":"10.1016/j.geothermics.2025.103370","url":null,"abstract":"<div><div>The volcanic complex of Cerro Machín is located on the eastern flank of Colombia’s Cordillera Central. It exhibits complex geological and geothermal features indicative of a significant subsurface geothermal reservoir. This study proposes the first joint interpretation of passive 3D seismic tomography and magnetotelluric resistivity modeling to characterize the geothermal potential of the Cerro Machín area. Seismic data recorded from 1998 to 2019 are used to generate P wave velocity and Vp/Vs ratio models down to 8 km below sea, level (b.s.l.), Additionally, statistical analysis of the seismicity is used to refine the data interpretation. Magnetotelluric data acquired in 2019, are used to generate a high-resolution resistivity model to depths of 5.1 km. The results are then combined to propose an integral model where a high resistivity sealing cup is topping a vertically elongated low Vp, low Vp/Vs and low resistivity body beneath the Cerro Machín Volcano. These bodies reach depths of ∼2 km b.s.l., providing useful information about the lateral and vertical extension of a potential geothermal reservoir. Additionally, a high Vp body identified at 2–3 km b.s.l. is compatible with the expression of a magmatic heat source that possibly is feeding the system. The distribution of seismic clusters, b-values, and resistivity patterns further delineates fluid pathways, likely controlled by fault zones or the volcanic domes conduits. These findings provide key insights on the structure of an ongoing state of the Cerro Machin volcanic complex that can be used for future exploration and support for the Colombia’s geothermal energy initiatives.</div></div>","PeriodicalId":55095,"journal":{"name":"Geothermics","volume":"131 ","pages":"Article 103370"},"PeriodicalIF":3.5,"publicationDate":"2025-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143900243","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Heat flux evaluation based on active fiber optic distributed temperature sensing tests in southwestern Yukon, Canada","authors":"Fiona Margaret Chapman ,&nbsp;Maria Klepikova ,&nbsp;Olivier Bour ,&nbsp;Mafalda Miranda ,&nbsp;Renaud Soucy La Roche ,&nbsp;Jasmin Raymond","doi":"10.1016/j.geothermics.2025.103354","DOIUrl":"10.1016/j.geothermics.2025.103354","url":null,"abstract":"<div><div>Geothermal energy could decrease remote regions dependence on diesel by offering an alternative baseload energy. However, the geothermal exploration risk is high in remote regions due to limited temperature and ground thermal conductivity data, and resultant heat flux evaluations. Thermal response tests are commonly used in the heat pump industry to evaluate the effective thermal conductivity, but these tests are typically performed in shallow wells (&lt; 200 m), assume the effective thermal conductivity to be purely due to conduction and neglect the influence of groundwater flow. Herein, fibre-optic distributed temperature sensing was used during active thermal response tests to produce a high-resolution in-situ effective thermal conductivity profile. The high-resolution profiles allow conduction-dominated segments to be isolated based on the temperature and effective thermal conductivity profiles. This method was applied to two boreholes in southwestern Yukon on the traditional territory of Kluane First Nation (KFN-L: 387 m and DRGW: 220 m). The heat flux was evaluated based on conductive segments of the temperature and thermal conductivity profiles. The temperature profile was corrected for topography and paleoclimate effects, and the internal heat generation was also considered. This resulted in heat flux estimation of 89 mW m^-2 and 99 mWm^-2 at KFN-L and DRGW, respectively. These values decrease exploration uncertainty around Burwash Landing, Yukon, where data scarcity is a challenge to geothermal exploration. This method could be applied in diverse geological settings to confidently estimate local terrestrial heat flux in pre-existing boreholes.</div></div>","PeriodicalId":55095,"journal":{"name":"Geothermics","volume":"131 ","pages":"Article 103354"},"PeriodicalIF":3.5,"publicationDate":"2025-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143902196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimization and behavior result analysis of a solar assisted ground source heat pump system using TRNSYS simulation tool","authors":"Nabiha Naili,&nbsp;Omeima Nouicer,&nbsp;Issam Attar,&nbsp;Ghofrane Mgadmi","doi":"10.1016/j.geothermics.2025.103353","DOIUrl":"10.1016/j.geothermics.2025.103353","url":null,"abstract":"<div><div>In this paper, a mathematical model, developed using TRNSYS software and validated against experimental data, is employed to conduct a multi-objective design optimization for a solar-assisted ground source heat pump (SAGSHP) system. The SAGSHP system consists of a vertical borehole U-tube ground heat exchanger (GHE) and an integrated solar flat-plate collectors (SFC), which are used to meet the space heating needs of a typical household in the climatic conditions of Northern Tunisia. The average coefficient of performance of the geothermal heat pump (COP_HP) is used as an evaluation parameter to optimize the sub-systems of the SAGSHP: the U-tube GHE, the heat pump (GHP), the SFC, and the radiant floor heating system (RFH). The optimization process determines the number of U-tube GHEs, their depth, the mass flow rate of the circulating fluid in each U-tube, the pipe spacing of the RFH, the mass flow rate in the RFH, and the surface area of the SFC as well as the fluid mass flow rate circulating in the collectors. The optimized solution is then used in a case study to assess the feasibility of using the SAGSHP system for space heating in a household with an area of 145 m² and a heating load of 12 kW.</div><div>Simulation results show that the energy recovered from the ground via U-tube GHE is 80 kW, the heat pump delivered energy is 95 kW, the SFC contributes by 27 % of the required heating energy during sunny period and the geothermal heat pump’s coefficient of performance is 4,45.</div></div>","PeriodicalId":55095,"journal":{"name":"Geothermics","volume":"131 ","pages":"Article 103353"},"PeriodicalIF":3.5,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143892022","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental investigation of shear in granite fractures at Utah FORGE: Implications for EGS reservoir stimulation","authors":"U.C. Iyare ,&nbsp;L.P. Frash ,&nbsp;B. K C ,&nbsp;M. Meng ,&nbsp;W. Li ,&nbsp;Y. Madenova ,&nbsp;S.K. Peterson ,&nbsp;M.R. Gross ,&nbsp;M.M. Smith ,&nbsp;K.A. Kroll","doi":"10.1016/j.geothermics.2025.103344","DOIUrl":"10.1016/j.geothermics.2025.103344","url":null,"abstract":"<div><div>Efficient heat transfer from hot dry rock to a working fluid requires the large surface area provided by fractures. These fractures are likely to include both tensile hydraulic fractures and natural shear fractures and faults. Maintaining flow through these fractures is vital for the performance of Enhanced Geothermal Systems (EGS). Among numerous prior studies, there remains a lack of laboratory measurements to quantify shear fracture evolution in the coupled thermal, hydraulic, mechanical, and chemical (THMC) environment of a geothermal reservoir. To address this, we conducted triaxial direct-shear tests on crystalline, granitic rock samples from the Utah Frontier Observatory for Research in Geothermal Energy (Utah-FORGE) site in Milford, Utah. We measured fracture permeability, aperture, strength, deformation, and effluent chemistry before and after shear slip under in-situ conditions at the Utah-FORGE site – replicating stress, pressure, temperature, minerology, and injectate water chemistry. Our results show that shear displacement can increase fracture permeability by up to an order of magnitude (factor of ∼10); however, in some cases, permeability decreased by up to two orders of magnitude (factor of ∼0.01), due to gouge formation, chemical alteration, stress cycling, and changes in surface roughness. Our tests also indicate in-situ shear is likely to produce smooth-planar shear surfaces (e.g., dilation angles &lt;7°), akin to slickensides, which reduces the benefit of shear fracture stimulation. Effluent analysis confirms rapid silicate and halite mineral dissolution and magnesium precipitation on FORGE samples, especially after shear stimulation. Our work provides key new measurements for modelling Utah-FORGE and similar granitic geothermal prospects.</div></div>","PeriodicalId":55095,"journal":{"name":"Geothermics","volume":"131 ","pages":"Article 103344"},"PeriodicalIF":3.5,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143895159","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reaction between in-situ generated acid and carbonate rock at ultra-high temperatures: A fusion of kinetic mechanisms and experiments","authors":"PingLi Liu ,&nbsp;Guan Wang ,&nbsp;Hongzhong Zhang ,&nbsp;Juan Du ,&nbsp;Xiang Chen ,&nbsp;Xin Zhang ,&nbsp;Chengjie Wang ,&nbsp;Jinming Liu ,&nbsp;Wenhao Tian ,&nbsp;Haoran Gu","doi":"10.1016/j.geothermics.2025.103357","DOIUrl":"10.1016/j.geothermics.2025.103357","url":null,"abstract":"<div><div>With the advancement of exploration, carbonate resource development has progressed to ultra-deep layers, with reservoir temperatures rising to ultra-high levels (&gt;180 °C). Effective acid fracturing under such conditions requires optimizing acid formulations and understanding acid-rock reaction mechanisms. This study optimized the formulation of in-situ generated acid for ultra-high temperatures and analyzed its acidogenic properties, dissolving capacity. The acid-rock reaction rate was measured using Rotating Disk Apparatus (RDA) and the effect of different factors on the reaction rate was analyzed. Experimental results showed that the optimal acid formulation involved a 1:1.5 molar ratio of ammonium chloride (NH₄Cl) to polyformaldehyde (POM) and a total concentration of 30 %. Acidogenic concentration initially increased rapidly, plateaued, and declined at higher temperatures due to formaldehyde volatilization and decomposition. At 180 °C, higher acid concentrations enhanced reaction rates, intensifying surface etching on limestone and dolomite. Reaction rates decreased with rising temperatures, primarily governed by acidogenic concentration. Increased rotational speed transformed the surface from flat to rough, forming central humps and cavities, with etching pits extending from rock edge to center. Linear velocity significantly influenced reaction rates and etching patterns. Larger cores experienced higher linear velocities at the same rotational speed, resulting to increased reaction rates without area-volume ratio corrections. After correction, differences in reaction rates across core sizes were significantly reduced, with etching morphologies at lower speeds resembling those of smaller cores at higher speeds. This work provided theoretical support for the application of in-situ generated acid in acid fracturing of ultra-high temperature carbonate reservoirs.</div></div>","PeriodicalId":55095,"journal":{"name":"Geothermics","volume":"131 ","pages":"Article 103357"},"PeriodicalIF":3.5,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143892020","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reliability and variability in thermal conductivity measurements: A comparison of CIT-TRT and conventional TRT in Japan","authors":"Saeid Mohammadzadeh Bina ,&nbsp;Hikari Fujii ,&nbsp;Eri Ohira ,&nbsp;Hiroyuki Kosukegawa ,&nbsp;Retsu Harada","doi":"10.1016/j.geothermics.2025.103360","DOIUrl":"10.1016/j.geothermics.2025.103360","url":null,"abstract":"<div><div>This study evaluates the effectiveness of the inverse heat exchange rate (1/q') method for estimating thermal conductivity of the ground using data from the constant inlet temperature thermal response test (CIT-TRT). In total seven TRTs including constant heat load TRT (conventional) and CIT-TRT were conducted in two different locations in Japan to compare the results of this method with those obtained from the Horner plot method and logarithmic graphical method for the conventional TRTs. The findings indicated that the estimated thermal conductivities using this method deviated by only 3.5% from those determined using the Horner plot method, confirming the applicability of this approach. In addition, the results from the CIT-TRT were compared with those obtained from the conventional TRT, which demonstrated the validity of the 1/q' method. Furthermore, the CIT-TRT was performed using two different inlet temperatures, 25°C and 35°C, to evaluate the effectiveness of this method under conditions with a limited heat load power. The results showed that the lower inlet temperature produced acceptable outcomes, though it was only 5°C above the initial ground temperature in the region. As the main achievement of this research, the 1/q′ method is shown to offer a practical and efficient approach for thermal conductivity estimation in CIT-TRTs, significantly reducing computational time while maintaining accuracy across varying inlet temperatures, GHE configurations (single or double U-tubes), and diverse geological conditions.</div></div>","PeriodicalId":55095,"journal":{"name":"Geothermics","volume":"131 ","pages":"Article 103360"},"PeriodicalIF":3.5,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143892019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Potential supercritical geothermal resources characterised by numerical modelling of fluid flow and heat transport in the Yuzawa area, Akita, Japan","authors":"Koichi Yokoi ,&nbsp;Tateyuki Negi ,&nbsp;Shohta Shimizu ,&nbsp;Guanhong Feng ,&nbsp;Tianfu Xu ,&nbsp;Norifumi Todaka","doi":"10.1016/j.geothermics.2025.103355","DOIUrl":"10.1016/j.geothermics.2025.103355","url":null,"abstract":"<div><div>The Yuzawa area in Japan hosts an active geothermal field. In this study, we combined magnetotelluric (MT) resistivity measurements, microearthquake surveys, and numerical modelling of fluid flow and heat transport to constrain the potential existence of supercritical resources in the Yuzawa area. The numerical model was calibrated based on geological, geophysical, geochemical, and drilling data, and included an intrusive heat source that was spatially inferred by the MT survey. The quasi-static state model results match the observed temperatures and pressures in exploratory wells, as well as the heat source from surface manifestations. An inferred zone with supercritical temperatures forms beneath a zone of intensive silica precipitation, which coincides with the brittle–ductile transition, as mapped from microearthquake hypocentres. Preliminary production forecasts of the supercritical zone show that the fracture permeability controls the enthalpy and mass flow rate, with increasing permeability leading to a higher mass flow rate but a lower fluid enthalpy. This study contributes to a deeper understanding of the structure and characteristics of supercritical geothermal resources in the Yuzawa area.</div></div>","PeriodicalId":55095,"journal":{"name":"Geothermics","volume":"131 ","pages":"Article 103355"},"PeriodicalIF":3.5,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143892021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Top-Down Cooling and Its Role in Sustaining the Laugarnes Geothermal Field, Iceland","authors":"Adolph Bravo Jr. ,&nbsp;Samuel Scott ,&nbsp;Halldór Pálsson ,&nbsp;Gunnar Gunnarsson","doi":"10.1016/j.geothermics.2025.103358","DOIUrl":"10.1016/j.geothermics.2025.103358","url":null,"abstract":"<div><div>The Laugarnes geothermal field is a low-temperature system (&lt;150 °C) that supplies an average of 80 MW_th for district heating in Reykjavík. Over nearly a century of operation, the field has maintained stable pressures and discharge temperatures. Despite its longevity, the processes sustaining the reservoir's response to production are still not fully understood. This study analyzes long-term production and field data, revealing a \"top-down\" cooling pattern attributed to the recharge of cooler surface waters into shallow reservoir rocks. This phenomenon is then integrated into a new conceptual model of the field. Energy balance calculations – accounting for basal conductive heat flux, drawdown-induced surface recharge, and the associated cooling of the rock – demonstrate that formation cooling constitutes a significant heat source during production. A 3D numerical model, calibrated against natural-state temperature and pressure history, reproduces the observed temperature changes, further supporting the importance of heat extraction from the rock formation. The findings suggest an alternative paradigm for the understanding heat budget and transport in Laugarnes and highlight the broader relevance of recharge-driven heat extraction in low-temperature systems. Therefore, considering this process is crucial for accurately characterizing low-temperature systems and ensuring their sustainable use.</div></div>","PeriodicalId":55095,"journal":{"name":"Geothermics","volume":"131 ","pages":"Article 103358"},"PeriodicalIF":3.5,"publicationDate":"2025-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143882442","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}