Geothermics最新文献

{"title":"Deep thermal state on the southern margin of the Zhangzhou Basin based on the electrical conductivity model","authors":"Chaofeng Wu ,&nbsp;Dong Xu ,&nbsp;Shuojian Yang ,&nbsp;Yixin Ye","doi":"10.1016/j.geothermics.2024.103188","DOIUrl":"10.1016/j.geothermics.2024.103188","url":null,"abstract":"<div><div>Exploring the internal spatial and thermal structure of the Zhangzhou Basin is of great scientific significance in understanding the properties of the deep heat sources and the heating mechanism of hot springs in this region. This study estimates the temperature distribution within the upper mantle of the Basin's southern margin using the Arrhenius equation and Hashin-Shtrikman bounds based on a two-dimensional crust-mantle electrical resistivity model. We also employ a layered simulation technique to calculate the crustal temperature distribution using a one-dimensional steady-state heat conduction equation, constrained by the upper mantle's top and ground surface temperatures. This approach displays the characteristics of the longitudinal variations and horizontal inhomogeneities in crust-mantle temperature. Additionally, we estimate the heat flow values within the study area. Our findings reveal that: (i) the upper mantle (at depths of 30 - 50 km) exhibits a temperature range of 700 - 1100 °C, with the presence of local Moho and upper mantle uplifts; (ii) the crustal temperature spans from 21 - 900 °C, with a diminishing influence of the upper mantle uplift area on crustal temperature at shallower depths; (iii) the surface heat flow values derived from our simulations range between 87 and 100 mW/m², averaging at 93.23 mW/m²; (iv) the exploration of dry heat rock in this region is likely to reach a depth of at least 6 km. These results suggest that the genesis of hot springs in the study area is not solely influenced by the heat energy extracted from large-area granitic surrounding rocks during a long transport process, but is also considerably affected by local deep thermal anomalous bodies and deep-large faults.</div></div>","PeriodicalId":55095,"journal":{"name":"Geothermics","volume":"125 ","pages":"Article 103188"},"PeriodicalIF":3.5,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142554569","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Natural recovery from Fe-oxyhydroxide clogging of a geothermal well in Osaka, Japan","authors":"Harue Masuda ,&nbsp;Yasuhisa Nakaso ,&nbsp;Masaki Nakao ,&nbsp;Linri Cui","doi":"10.1016/j.geothermics.2024.103187","DOIUrl":"10.1016/j.geothermics.2024.103187","url":null,"abstract":"<div><div>Causes of clogging and the following unique recovering process of an ATES (Aquifer Thermal Energy Storage) system in Maishima (Osaka, Japan) are documented based on the geochemical analyses of groundwater and stagnant water in the system. Fe-oxyhydroxides precipitation clogged screens in an ATES geothermal well during cooling operation. Chemical analyses of waters in the aquifers and plumbing pipes found out that oxidation of dissolved Fe occurred in association with intrusion of ambient air, which was leaked through inadvertently opened air bent valve, into the well. Dual heat-extraction system was installed in the two aquifers of the same wells separated by packers, and the closing occurred in the plumbing pipe installed in the shallow aquifer of one of the thermal wells. This aquifer could not be used as the ATES until when the Fe-oxyhydroxides were naturally dissolved in about a half year after the clogging. Then, the ATES system recovered to be useful. Increasing dissolved Fe with increasing NH₄⁺ and decreasing oxidation–reduction potential indicated that the Fe-oxyhydroxides were dissolved by microbially induced reduction reactions. This case suggests that some clogs can be mitigated without chemical and/or physical treatment, and that monitoring of groundwater chemistry is essential for diagnosing and treating clogs.</div></div>","PeriodicalId":55095,"journal":{"name":"Geothermics","volume":"125 ","pages":"Article 103187"},"PeriodicalIF":3.5,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142531420","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical modeling of the Nevados de Chillán fractured geothermal reservoir","authors":"Isa Oyarzo-Céspedes ,&nbsp;Gloria Arancibia ,&nbsp;John Browning ,&nbsp;Jorge G.F. Crempien ,&nbsp;Diego Morata ,&nbsp;Valentina Mura ,&nbsp;Camila López-Contreras ,&nbsp;Santiago Maza","doi":"10.1016/j.geothermics.2024.103181","DOIUrl":"10.1016/j.geothermics.2024.103181","url":null,"abstract":"<div><div>Numerical models can be utilized to understand and anticipate the future behavior of a geothermal reservoir, and hence aid in the development of efficient reservoir engineering strategies. However, as each system has a unique geological context, individual characterization is required. In this research, the Nevados de Chillán Geothermal System (NChGS) in the Southern Volcanic Zone of the Andes is considered. The NChGS is controlled by the geology of the active Nevados de Chillán Volcanic Complex (NChVC) including their basement units (Miocene lavas and volcaniclastic layers from Cura-Mallín Formation and the Miocene, Santa Gertrudis granitoids) as well as the key structural control from crustal scale faults, all of which combine to influence the reservoir characteristics. The presence of faults acts to generate a high secondary permeability which favors the circulation of hydrothermal fluids. Based on previous studies in the NChGS, we designed a thermo-hydraulic model in COMSOL Multiphysics® combining equations of heat transfer and Darcy's law in order to determine the distribution of isotherms and surface heat flux. The boundary conditions of the model were informed by a conceptual model of depth 3 km and width of 6.6 km which considers a highly fractured granitic reservoir, a clay cap behavior of Miocene lavas and volcaniclastic units, and transitional zones between a regional zone and the reservoir. A low-angle reverse fault affecting the clay cap unit was also incorporated into the models. Results indicate convective behavior in the reservoir zone and a surface heat flux of 0.102 W/m² with a local peak up to 0.740 W/m² in the area affected by the low-angle reverse fault zone. The models suggest hydrothermal fluid residence times of around 9–15 thousand years are required to reach a steady-state thermal configuration, which is consistent with the deglaciation age proposed for the NChVC latitude of the complex (<em>c.</em> 10–15 ka). Permeability in the fractured reservoir is one of the most complex parameters to estimate and the most sensitive and hence requires further constraint. Finally, using the volumetric method and the results obtained in this research, we estimate a geothermal potential of 39 ± 1 MWe for the NChGS.</div></div>","PeriodicalId":55095,"journal":{"name":"Geothermics","volume":"125 ","pages":"Article 103181"},"PeriodicalIF":3.5,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142531180","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":"Modeling proppant transport and settlement in 3D fracture networks in geothermal reservoirs","authors":"Baohua Liu,&nbsp;Dharmendra Kumar,&nbsp;Ahmad Ghassemi","doi":"10.1016/j.geothermics.2024.103176","DOIUrl":"10.1016/j.geothermics.2024.103176","url":null,"abstract":"<div><div>In this paper, we develop an efficient proppant transport model using the Eulerian-Eulerian approach for simulating proppant transport in fractures and 3D fracture networks in geothermal reservoirs. The proposed model accounts for proppant settling, pack/bed formation, bridging/screenout, proppant concentration effect, fracture wall effect, and the transition from Poiseuille flow (fracture channel) to Darcy flow (proppant pack). Notably, the heat transfer process and its impact on proppant transport are also considered—a facet often overlooked in previous proppant transport models. A three-dimensional displacement discontinuity method (3D DDM) that incorporates the stress shadow effect is employed to generate the fracture geometry. The governing equations for slurry flow, proppant transport, and heat transfer are discretized and solved using the finite volume method (FVM). The model is verified against analytical solutions and published experimental data, demonstrating good agreement with these references. To demonstrate the proposed model, we applied it to both low-temperature (depleted hydrocarbon wells) and high-temperature (dry hot rocks) enhanced geothermal systems (EGS). The simulation results highlight the significant influence of reservoir temperature on proppant transport and settlement in a reservoir environment. Heating of the slurry by higher temperature reservoir rocks reduces fluid viscosity and accelerates proppant settling, thereby shortening the transport distance and reducing the coverage area of the proppant. Both ultra-light and micro-proppant are effective in mitigating proppant settlement in enhanced geothermal systems. However, proppant is susceptible to bridging at fracture intersections, where the fracture widths are narrower due to more pronounced stress shadow effects in these areas. Consequently, the use of micro-proppant could offer substantial benefits over ultra-light proppant in enhancing proppant coverage area in enhanced geothermal systems.</div></div>","PeriodicalId":55095,"journal":{"name":"Geothermics","volume":"125 ","pages":"Article 103176"},"PeriodicalIF":3.5,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142531181","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":"Three-dimensional electrical imaging of the Aravali-Tural-Rajwadi geothermal system, West Coast of India","authors":"Khasi Raju ,&nbsp;Vasu Deshmukh ,&nbsp;P.V. Vijaya Kumar ,&nbsp;P.B.V. Subba Rao ,&nbsp;A.K. Singh","doi":"10.1016/j.geothermics.2024.103185","DOIUrl":"10.1016/j.geothermics.2024.103185","url":null,"abstract":"<div><div>The West Coast geothermal system is a prominent geothermal region in the Indian subcontinent, and understanding its geothermal reservoirs is crucial for societal benefits. In the present study, we employed 3D modeling of Audio and broad-band Magnetotelluric (AMT &amp; MT) data for the first time in the West Coast geothermal region, covering the Aravali, Tural, and Rajwadi geothermal zones, to gain insights into the evolution of geothermal zone and geothermal reservoir characteristics. The 3D inversion results revealed the presence of a thin layer of granitic crustal layer, which decreases in thickness towards the west. The rifting process along the western continental margin of India has introduced magmatism (underplated) to the crustal level, which manifests as a moderate conductivity (100–500 Ωm) layer in shallow depths (∼10 km). The cooling and solidification of underplating materials contribute to the heat flux along the West Coast geothermal zone (WCGZ). The circulation of meteoric water within the deep layers gets heated up by these mantle materials and is ejected along the fracture and fault zones that appear as hot springs. Considering a thin crustal layer, a shallow Moho, and an upwelling asthenosphere along the west coast, the WCGZ is considered a convective geothermal play type. This study enhances an understanding of the WCGZ geothermal potential and geological processes, which can have significant implications for harnessing this valuable energy resource.</div></div>","PeriodicalId":55095,"journal":{"name":"Geothermics","volume":"125 ","pages":"Article 103185"},"PeriodicalIF":3.5,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142531179","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 and numerical research on the thermal performance of a vertical earth-to-air heat exchanger system","authors":"Kailiang Huang ,&nbsp;Qihai Sun ,&nbsp;Guohui Feng ,&nbsp;Lei Zhang ,&nbsp;Ainong Li ,&nbsp;Jiaxing Wei ,&nbsp;Xiao Zhang ,&nbsp;Xianghua Meng","doi":"10.1016/j.geothermics.2024.103182","DOIUrl":"10.1016/j.geothermics.2024.103182","url":null,"abstract":"<div><div>The Earth-to-Air Heat Exchanger (EAHE) system is an efficient and clean geothermal application technology that can be used for pre-cooling in summer and heating in winter. This paper proposes a novel Vertical Earth-to-Air Heat Exchanger (VEAHE) system that uses baffles to divide the vertical duct into two ventilation tunnels with a hollow area at the bottom for air circulation. This system occupies a small land area and has a relatively high geothermal energy utilization efficiency. This study evaluates the thermal performance of the system through experimental tests under various operating conditions. Additionally, a numerical model of the system was established to explore the influence of baffles length, thickness, and duct depth on its thermal performance. The experimental results show that the 2.5-meter deep VEAHE system achieves an average air pre-cooling temperature reduction of 5.42 °C, with a maximum temperature reduction of up to 7.58 °C. Below the 1.2-meter mark of the system, the cooling capacity of the descending pipe is 1.52 times that of the ascending pipe. The simulation showed a Maximum Absolute Relative Error (MARE) of 3.15 % compared to the experimental results. As the length and thickness of the baffles, duct length, and soil thermal conductivity increase, the average outlet air temperature gradually decreases, while the system's heat exchange capacity significantly improves, in contrast to the duct diameter. Among the influencing factors, the duct length has the greatest impact on the system. Under the recommended configuration, the system's maximum pre-cooling potential is 915.90 W, with the outlet air temperature ranging from 12.05 °C to 14.79 °C.</div></div>","PeriodicalId":55095,"journal":{"name":"Geothermics","volume":"125 ","pages":"Article 103182"},"PeriodicalIF":3.5,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142442824","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":"Macroscopic permeability progression of Nanan granite under confining pressures and its microscopic evolution after cooling at atmospheric pressure: A comparative study","authors":"Zhennan Zhu ,&nbsp;Wangxing Hong ,&nbsp;Shengqi Yang ,&nbsp;Ting Bao ,&nbsp;Jingyu Xie ,&nbsp;Hao Fan ,&nbsp;Yilong Yuan ,&nbsp;Yu Zhang ,&nbsp;Hong Tian ,&nbsp;Jun Zheng ,&nbsp;Jin Chen ,&nbsp;Guosheng Jiang","doi":"10.1016/j.geothermics.2024.103180","DOIUrl":"10.1016/j.geothermics.2024.103180","url":null,"abstract":"<div><div>Permeability is one of the key factors for influencing the mass transfer behavior in rocks and plays a key role in heat extraction of enhanced geothermal systems (EGSs), so the practice of EGSs needs cooling water to be injected to enhance the permeability within geothermal reservoirs. Macroscopic and microscopic experimental investigation on how cool water affects permeability evolution is still limited. To solve this, we experimentally explored the permeability evolution of Nanan granite after air and water cooling under different confining pressures combined with optical microscopy and X-ray micro computed tomography (CT) observation. Lots of microdefects were observed in Nanan granite after two cooling paths, which dominantly drives the evolution of permeability from a microscopic scale. The permeabilities of granite under water-cooling conditions are always larger than those under air-cooling conditions, because the comparison shows that water-cooling treatment enhances the permeability of specimens. The permeabilities of granite specimens after two cooling paths decrease with the confining stress. More microcracks and better connectivity among microcracks produce a larger permeability within the specimen after water cooling. The observed microcracks are regarded as the seepage channels and direct microscale evidence of the permeability evolution of granite after two cooling paths. Our results provide support that cooled water injection is an efficient way for permeability enhancement due to thermal microcracks propagation in thermal simulation.</div></div>","PeriodicalId":55095,"journal":{"name":"Geothermics","volume":"125 ","pages":"Article 103180"},"PeriodicalIF":3.5,"publicationDate":"2024-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142433394","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":"Damage characteristics of high-temperature coal under different cooling rates","authors":"Su Wang ,&nbsp;Hanpeng Wang ,&nbsp;Wei Wang ,&nbsp;Bing Zhang ,&nbsp;Youshi Wang ,&nbsp;Dekang Sun","doi":"10.1016/j.geothermics.2024.103179","DOIUrl":"10.1016/j.geothermics.2024.103179","url":null,"abstract":"<div><div>The damage characteristics of high-temperature coal under water cooling was analyzed.As the heating temperature increases, the internal pore development and crack propagation in coal intensify, with the failure mode gradually shifting from brittle to plastic. There exists a threshold temperature that accelerates damage. The rapid temperature drop caused by water cooling accelerates damage and cracking in the coal. The thermal shock factor resulting from the rapid temperature drop can quantitatively represent the damage induced by water cooling. The results are expected to provide guidance for the utilization of thermal energy in coal field fire areas.</div></div>","PeriodicalId":55095,"journal":{"name":"Geothermics","volume":"125 ","pages":"Article 103179"},"PeriodicalIF":3.5,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142423788","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":"Breakage mechanism analysis of bedded sandstone impacted by abrasive water jet using an integrated SPH-DEM-FEM and cohesive element method","authors":"Zhe Zhou ,&nbsp;Chao Tian ,&nbsp;Zhaolong Ge ,&nbsp;Zhongtan Li ,&nbsp;Qinglin Deng","doi":"10.1016/j.geothermics.2024.103177","DOIUrl":"10.1016/j.geothermics.2024.103177","url":null,"abstract":"<div><div>Abrasive water jet (AWJ) is an emerging technique for improving the drilling efficiency for geothermal energy development. Rock bedding significantly influences the effectiveness of rock breaking during drilling. In this study, to investigate the damage modes and the mechanism of the bedded sandstone under abrasive water jet erosion, smooth particle hydrodynamics (SPH) and discrete element method (DEM) are used to establish the jet, and cohesive elements are inserted into finite elements to model the bedded sandstone, simulating the process of water and abrasive into the nozzle to form an abrasive water jet impacting bedded sandstone. The numerical results showed that the depth and diameter of fractures in bedded sandstone decrease and then stabilize as the bedding angle increases under AWJ, and the error in the ratio of erosion hole diameter and depth between the simulated and experimental results was &lt;10.8 %. In addition, two damage modes of the bedded sandstone were determined, which include Case I damage mode: the sandstone is well consolidated, and the damage is in the form of erosion holes (0°≤α≤60°), dominated by the tensile damage, and Case II damage mode: the rock is fractured along the bedding and splits into two halves (60°&lt;α≤90°), and the process can be divided into two stages during this mode. The first stage is the impact kinetic energy carried by the jet to form a crater, and the second stage is the water wedge effect to fracture the rock. The results of this study complement the damage mechanism of fractured bedded rocks by AWJ, which provides a theoretical reference for the application of AWJ to break bedded rocks in subsurface energy extraction.</div></div>","PeriodicalId":55095,"journal":{"name":"Geothermics","volume":"125 ","pages":"Article 103177"},"PeriodicalIF":3.5,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142424416","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":"Effects of carbon dioxide blasting on hot dry rock reservoirs considering thermal damage","authors":"Xiecai Yan ,&nbsp;Jun Zheng ,&nbsp;Wan Sun ,&nbsp;Wentao Cai ,&nbsp;Bin Dou ,&nbsp;Xiaotian Lai ,&nbsp;Tianyu Wu","doi":"10.1016/j.geothermics.2024.103174","DOIUrl":"10.1016/j.geothermics.2024.103174","url":null,"abstract":"<div><div>A cutting-edge technique for igniting hot dry rock (HDR) reservoirs is carbon dioxide blasting. The cooling effect of the drilling fluid was taken into consideration during a numerical simulation of the action range of carbon dioxide blasting-induced cracking. A temperature difference was used to determine the reservoir's material properties. Additionally, temperature distribution functions were used to create the temperature field in the reservoir. The blasting load is calculated using the pertinent theories and formulas of explosive blasting, and the process of blasting carbon dioxide to excite the HDR reservoir is modeled using COMSOL. The findings show that several stress concentrations take place during the blasting process. The fracture zone is created by the tensile stress concentration outside of the crushing zone, whereas the compressive stress concentration close to the blast hole creates the crushing zone. Furthermore, the effectiveness of carbon dioxide blasting fracturing would be affected by the beginning temperature and pressure plate thickness. Although the scope of the fracture zone is mostly unchanged, the initial temperature has a significant impact on the blasting crushing zone. The size of the crushing zone, which determines how the blasting fracture zone is distributed, is unaffected by the pressure plate's thickness.</div></div>","PeriodicalId":55095,"journal":{"name":"Geothermics","volume":"125 ","pages":"Article 103174"},"PeriodicalIF":3.5,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142424415","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}