IF 3.9 2区工程技术 Q3 ENERGY & FUELS

Geothermics

Pub Date : 2026-01-31 DOI: 10.1016/j.geothermics.2026.103614

Wenjie Sun , Jiabin Duan , Mingliang Liu , Fangyang Hu , Xiaodong Jiang , Yanlong Kong

Geothermal waters in certain regions of Tibet, particularly those characterized by intense tectonic activity, are exceptionally enriched in lithium (Li), rubidium (Rb), and cesium (Cs). However, the primary sources of these elements within Tibetan geothermal systems remain debated. Clarifying whether these elements are derived predominantly from water-rock interaction or magmatic fluid input is essential for a comprehensive understanding of the region’s geothermal systems. Previous studies lacked quantitative analysis methods using water-rock interaction simulation experiments. To address this gap, we conducted laboratory simulations using 10-million-years-old biotite granite from the Yangbajing area, performing high-temperature and high-pressure experiments at 200 °C and 20 MPa over 62 days. The results yield a Li:Rb:Cs ratio of approximately 48:64:1, which starkly contrast with the ratio observed in natural geothermal waters (around 5.7:1:2.1). This significant discrepancy suggests that there must be an additional geochemical process that strongly modifies the Li, Rb, and Cs ratios in natural geothermal waters. Moreover, in the Yangbajing-Gulu rift, the concentrations of Li, Rb, and Cs show a strong correlation with Cl, a tracer indicative of magmatic fluid input, while the correlations between δ¹⁸O and the concentrations of Li, Rb, and Cs are weaker. The geothermal waters exhibit a Cs > Rb pattern, similar to other geothermal systems with magmatic fluid input. Combined with geophysical evidence of shallow melt bodies beneath the rift, these findings indicate that magmatic fluid input is a key factor controlling the enrichment of Li, Rb, and Cs in the geothermal waters of the Yangbajing-Gulu rift. This study highlights the magmatic source mechanism for rare metal supply in Tibetan geothermal waters and provides critical insights into the metallogenic models of Tibetan geothermal systems.

西藏部分地区地热水，特别是构造活动强烈的地热水，特别富含锂（Li）、铷（Rb）和铯（Cs）。然而，这些元素在西藏地热系统中的主要来源仍然存在争议。弄清这些元素主要来自水-岩相互作用还是岩浆流体输入，对于全面了解该地区的地热系统至关重要。以往的研究缺乏水岩相互作用模拟实验的定量分析方法。为了解决这一空白，我们利用杨八井地区1000万年历史的黑云母花岗岩进行了室内模拟，在200°C和20 MPa下进行了62天的高温高压实验。结果表明，Li:Rb:Cs的比值约为48:64:1，这与在天然地热水中观测到的比值（约5.7:1:2.1）形成鲜明对比。这一显著差异表明，一定存在一个额外的地球化学过程，强烈地改变了天然地热水中的Li、Rb和Cs比值。此外，在羊八井-古鲁裂谷中，Li、Rb和Cs的浓度与指示岩浆流体输入的示踪剂Cl的相关性较强，而δ¹⁸O与Li、Rb和Cs浓度的相关性较弱。地热水表现为Cs >； Rb型，与其他有岩浆流体输入的地热系统相似。结合裂谷下浅层熔体的地球物理证据，表明岩浆流体输入是控制羊八井-古陆裂谷地热水中Li、Rb、Cs富集的关键因素。本研究突出了西藏地热水中稀有金属的岩浆来源机制，为西藏地热系统的成矿模式提供了重要的认识。

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引用次数: 0

Hydrochemical evolution of hydrothermal systems driven by seawater mixing in the southeastern coastal region of China: insights from water chemistry and isotopes 中国东南沿海海水混合驱动的热液系统水化学演化：来自水化学和同位素的见解

IF 3.9 2区工程技术 Q3 ENERGY & FUELS

Geothermics

Pub Date : 2026-01-28 DOI: 10.1016/j.geothermics.2026.103616

Yongchao Cai , Chunlei Liu , Shengwei Cao , Jing Li , Yan Dong

Hydrothermal systems are extensively developed in the southeastern coastal region of China. However, their hydrochemical evolution following seawater mixing remains unclear. Based on hydrochemical and isotopic analyses (δ²H, δ¹⁸O, and δ³⁴S), this study investigates the origin of geothermal water, the degree of reservoir confinement, groundwater mobility, and the hydrochemical evolution induced by seawater mixing. According to the classification criteria of the United States Geological Survey (USGS), the geothermal waters were categorized into two types: coastal saline geothermal water (Group A, 7 samples near the coast) and hilly fresh geothermal water (Group B, 4 samples from inland hilly areas). Group A is recharged by both meteoric water and seawater, with seawater mixing ratios calculated from Cl⁻ and Br⁻ ranging from 2.61–72.97% and 2.10–88.24%, respectively. The two estimates are broadly consistent, although those based on Br⁻ exhibit a slightly higher maximum value. In contrast, Group B is recharged predominantly by meteoric water. Characteristic Na⁺/Cl⁻ and SO₄²⁻/Cl⁻ ratios suggest that the geothermal reservoirs of Group A are well confined with weak groundwater mobility, whereas those of Group B exhibit poor confinement and active groundwater mobility. Seawater mixing significantly enhances water–rock interactions: seawater mixing and high temperatures enhance silicate dissolution; cation exchange and chloritization alter the cation composition; microbial sulfate reduction modifies the sulfur isotopes and SO₄²⁻ concentration. This study reveals the hydrochemical evolution of coastal geothermal systems influenced by seawater mixing, providing insights for sustainable geothermal resource development.

热液系统在中国东南沿海地区广泛发育。然而，它们在海水混合后的水化学演变尚不清楚。基于水化学和同位素分析（δ2H、δ18O和δ34S），研究了地热水的成因、储层封闭程度、地下水流动性以及海水混合引起的水化学演化。根据美国地质调查局（USGS）的分类标准，将地热水分为两类：沿海咸水（A组，靠近海岸的7个样本）和丘陵淡水地热水（B组，来自内陆丘陵地区的4个样本）。A组由大气水和海水共同补给，由Cl−和Br−计算的海水混合比分别为2.61 ~ 72.97%和2.10 ~ 88.24%。这两种估计大体上是一致的，尽管基于Br−的估计显示出略高的最大值。相比之下，B群主要由大气水补给。Na+/Cl -和SO42 - /Cl -比值特征表明A组地热储层封闭程度较好，地下水活动性弱，B组地热储层封闭程度较差，地下水活动性强。海水混合显著增强水岩相互作用：海水混合和高温增强硅酸盐溶解；阳离子交换和氯化作用改变了阳离子组成；微生物硫酸盐还原改变了硫同位素和SO42−浓度。本研究揭示了海水混合作用下沿海地热系统的水化学演化，为地热资源的可持续开发提供参考。

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引用次数: 0

3D resistivity model of the los Humeros geothermal field in Mexico, based on magnetotelluric data 基于大地电磁资料的墨西哥los Humeros地热田三维电阻率模型

IF 3.9 2区工程技术 Q3 ENERGY & FUELS

Geothermics

Pub Date : 2026-01-24 DOI: 10.1016/j.geothermics.2025.103591

José M. Romo-Jones , Claudia Arango-Galván , Diego Ruiz-Aguilar , Gylfi Páll Hersir , Ásdís Benediktsdóttir , José L. Salas-Corrales , Thalia A. Esquivel-Avilés , Sebastian Held

A joint geothermal project of a European and Mexican consortium (the GEMex project) was carried out between 2016 and 2020 to develop geothermal energy in the easternmost region of the Trans-Mexican Volcanic Belt. GEMex project was funded by the European Union’s Horizon 2020 and SENER-CONACYT Mexican Energy Sustainability programs. One of the key outcomes is the 3D resistivity model of the Los Humeros geothermal field in Mexico, a potentially superheated geothermal reservoir, where fluid temperature reaches close to 400 °C in some areas, based on magnetotelluric (MT) data. The model reveals a shallow resistive zone linked to post-caldera volcanic rocks; underlying this horizon is an updoming conductive anomaly caused by smectite-rich hydrothermally altered rocks that act as cap-rock. Beneath this seal-cap, a deep dome-shaped resistive anomaly is observed, likely corresponding to andesitic reservoir rocks (50–100 Ohm-m) and deeper basement rocks, possibly limestone and granodiorite. This structure aligns with temperature measurements from boreholes, where the 250–300 °C isotherms follow the shape of the top of the resistive dome. The obtained 3D model successfully identifies deep faults that facilitate hot fluid circulation and define the structural limits of the Los Potreros caldera. Faults within the caldera collapse significantly disrupt the cap-rock and the top of the andesites that host the reservoir. This information, together with results derived from other geophysical, geological, and geochemical methods, will help to infer the location and depth at which high-temperature fluids might be found.

欧洲和墨西哥财团的一个联合地热项目（GEMex项目）于2016年至2020年期间进行，旨在开发跨墨西哥火山带最东部地区的地热能源。GEMex项目由欧盟的Horizon 2020和SENER-CONACYT墨西哥能源可持续发展项目资助。其中一个关键成果是基于大地电磁（MT）数据的墨西哥Los Humeros地热田的三维电阻率模型，这是一个潜在的过热地热储层，在某些地区流体温度接近400°C。该模型揭示了一个与后破火山口火山岩有关的浅层电阻带；在这个层位下面是一个由富蒙脱石热液蚀变岩引起的上凸起的导电异常，这些热液蚀变岩充当盖层。在该盖层下，观察到深部圆顶状电阻异常，可能对应于安山岩储集岩（50-100欧姆）和更深的基底岩，可能是灰岩和花岗闪长岩。这种结构与钻孔温度测量结果一致，其中250-300°C等温线遵循电阻圆顶顶部的形状。获得的三维模型成功地识别了有利于热流体循环的深层断层，并确定了Los potereros火山口的结构界限。火山口内的断层崩塌严重破坏了盖层和安山岩的顶部，安山岩承载着储层。这些信息，连同其他地球物理、地质和地球化学方法得出的结果，将有助于推断可能发现高温流体的位置和深度。

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引用次数: 0

Prioritizing resource protection and understanding potential susceptibility of springs to surficial changes in a low-temperature geothermal system 在低温地热系统中，优先考虑资源保护和了解温泉对地表变化的潜在敏感性

IF 3.9 2区工程技术 Q3 ENERGY & FUELS

Geothermics

Pub Date : 2026-01-24 DOI: 10.1016/j.geothermics.2026.103615

Connor P. Newman , Jeff D. Pepin

Geothermal systems are vulnerable to changes in water budget and composition, requiring science-based management. This study uses a dataset of spring water temperatures, time series of groundwater residence time tracers (tritium and carbon-14), and stable isotopes of water to understand geothermal flow in a low-temperature geothermal system in north west Colorado, United States (Steamboat Springs). The geothermal system is bisected by the Yampa River, necessitating a stream mass balance approach to quantify total discharge. Time series analysis of water temperature data provides a ranked list of features more susceptible to surficial changes, which is corroborated using time series of tritium which indicate spatially distinct patterns of mixing between modern and pre-modern groundwater. All springs contain a portion of pre-modern groundwater that is thousands to tens of thousands of years old, a period coinciding with melting of extensive Pleistocene glaciers that was likely one of the recharge sources to the geothermal system. Stream mass balance indicates that greater than 80% of the total geothermal discharge is derived from diffuse or small springs, highlighting the extensive nature of the geothermal outflow zone and the association with local geologic structures. This study provides baseline data to support management of the Steamboat Springs geothermal system and indicates the utility of these approaches in developing science-based geothermal management.

地热系统容易受到水收支和组成变化的影响，需要基于科学的管理。本研究利用泉水温度数据集、地下水停留时间示踪剂（氚和碳-14）时间序列和水的稳定同位素来了解美国科罗拉多州西北部（Steamboat Springs）低温地热系统中的地热流。地热系统被扬帕河（Yampa River）一分为二，因此需要采用溪流质量平衡方法来量化总排放量。水温数据的时间序列分析提供了一个更容易受地表变化影响的特征列表，这是用氚的时间序列证实的，它表明现代和前现代地下水之间的混合模式在空间上是不同的。所有的泉水都含有数千到数万年前的前现代地下水，这一时期与广泛的更新世冰川融化相吻合，而更新世冰川很可能是地热系统的补给来源之一。水流质量平衡表明，80%以上的地热流量来自漫射或小泉，突出了地热流出带的广泛性及其与当地地质构造的联系。本研究为蒸汽船温泉地热系统的管理提供了基础数据，并指出了这些方法在发展科学地热管理方面的效用。

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引用次数: 0

Identifying the genesis and evolution of geothermal water in the coal mining area, North China: Insights from hydrochemistry and δ2H, δ18O, δ13C, δ34S and 87Sr/86Sr isotopes 华北矿区地热水成因演化：水化学及δ2H、δ18O、δ13C、δ34S和87Sr/86Sr同位素的启示

IF 3.9 2区工程技术 Q3 ENERGY & FUELS

Geothermics

Pub Date : 2026-01-24 DOI: 10.1016/j.geothermics.2026.103611

Jie Zhang , Herong Gui , Luwang Chen , Manli Lin , Huifang Rong , Jun Li , Ruirui Li , Mingda Cao

Investigating geothermal resources in coal mining regions constitutes an important measure for promoting the green transformation of coal industry in China. In this study, the primary genesis and evolution of geothermal water in the southern Huaibei coalfield, North China was proposed based on hydrochemistry combining with multi-isotopes. The diversity of hydrochemical types and the variance of correlation coefficients among ions signify the complexity of hydrogeochemical processes in geothermal waters. The δD and δ¹⁸O values indicate that the geothermal water originated from paleo-meteoric water during the cold period. The dissolution of carbonate and sulfate minerals is the primary cause of the observed increase in δ¹³C_DIC and δ³⁴S_SO4 values with depth. Furthermore, the decrease in ⁸⁷Sr/⁸⁶Sr ratios with depth is jointly controlled by the composition of the recharge end-member and water-rock interactions. The maximum temperature of the geothermal reservoir calculated by silica geothermometers is 44.9 °C, with the corresponding circulation depth being 1282 m. The shallow cold water circulates to the depth along fissures, gets heated through thermal conduction and undergoes a series of water-rock interactions during the process, resulting in constant variations in the temperature and hydrogeochemistry. Given that deep geothermal water may ascend to the working face through fault zones and trigger water inrush disasters, it is currently managed primarily through controlled pumping and drainage. The findings of this work would provide a sound basis for the utilization of geothermal water in the Huaibei coalfield, as well as the majority of coalfields in North China.

开展矿区地热资源调查是推动中国煤炭产业绿色转型的重要举措。以水化学和多同位素相结合的方法，提出了淮北煤田南部地热水的主要成因和演化。水化学类型的多样性和各离子间相关系数的差异性反映了地热水水文地球化学过程的复杂性。δD值和δ18O值表明该区地热水来源于寒冷期的古大气水。碳酸盐岩和硫酸盐矿物的溶蚀作用是δ13CDIC和δ34SSO4值随深度增大的主要原因。87Sr/86Sr比值随深度的减小受补给端元组成和水岩相互作用的共同控制。石英地温计计算的地热储层最高温度为44.9℃，对应的循环深度为1282 m。浅层冷水沿裂隙向深部循环，通过热传导受热，并在此过程中发生一系列的水岩相互作用，导致温度和水文地球化学的不断变化。由于深部地热水可能通过断裂带上升到工作面，引发突水灾害，目前主要采用控制抽排的方式进行管理。研究结果将为淮北煤田以及华北大部分煤田地热水的开发利用提供理论依据。

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引用次数: 0

Reservoir temperature prediction utilizing a least squares boosting model optimized by kepler optimization algorithm 利用kepler优化算法优化的最小二乘提升模型预测储层温度

IF 3.9 2区工程技术 Q3 ENERGY & FUELS

Geothermics

Pub Date : 2026-01-24 DOI: 10.1016/j.geothermics.2026.103612

Ling Zhou , Xiangzhe Chen , Ruzhen Hu , Peng Yan , Jingchao Sun

Geothermal energy, as a renewable, sustainable, widely-distributed, stable and reliable energy source, holds significant potential in resolving the global energy crisis and reducing carbon emissions. The development of reservoir temperature prediction models is a crucial aspect for assessing this potential. In this context, machine learning has addressed the limitations of conventional approaches through its capacity to efficiently handle complex nonlinear problems, overcoming operational complexity, high costs, and substantial uncertainties associated with traditional methods. Therefore, this paper selected 120 data from Turkey and China to establish a machine learning model. The extreme gradient boosting (XGBoost) and Least Squares Boosting (LSBoost) models were trained with pH, EC, Na⁺, K⁺, SiO₂, and Cl^- as input features and reservoir temperature as the output feature. During the training process, LSBoost was also separately optimized for hyperparameters through Ivy algorithm (IVYA) and Kepler optimization algorithm (KOA), resulting in the Ivy algorithm based Least Squares Boosting (IVYA-LSB) and Kepler optimization algorithm based Least Squares Boosting (KOA-LSB) models. In order to achieve better prediction results, five evaluation indicators including Coefficient of determination (R²) were established to assess the performance of the models. The results show that the KOA-LSB model has the best predictive ability with an R² value of 0.98064 and can achieve accurate prediction of reservoir temperature. Furthermore, The acquisition of a deeper understanding of the relationship between reservoir temperature and various input feature values, Shapely Additive exPlanations (SHAP) analysis was adopted to conduct an interpretable analysis of the machine learning results. The results indicated that SiO₂ was the most significant factor influencing reservoir temperature, while pH was the least influential factor. This research not only proposes a novel machine learning method but also conducts an interpretable analysis of the machine learning results, providing reliable model selection tools for geothermal professionals while enhancing their confidence in machine learning and promoting a better understanding of geothermal resources.

地热能作为一种可再生、可持续、分布广泛、稳定可靠的能源，在解决全球能源危机、减少碳排放方面具有巨大潜力。开发储层温度预测模型是评估这种潜力的一个关键方面。在这种情况下，机器学习通过其有效处理复杂非线性问题的能力，克服了与传统方法相关的操作复杂性，高成本和大量不确定性，解决了传统方法的局限性。因此，本文选择了土耳其和中国的120个数据来建立机器学习模型。以pH、EC、Na+、K+、SiO2和Cl-为输入特征，以储层温度为输出特征，对极值梯度增压（XGBoost）和最小二乘增压（LSBoost）模型进行训练。在训练过程中，LSBoost还分别通过Ivy算法（IVYA）和Kepler优化算法（KOA）对超参数进行了优化，得到了基于Ivy算法的最小二乘Boosting （IVYA- lsb）和基于Kepler优化算法的最小二乘Boosting （KOA- lsb）模型。为了获得更好的预测结果，我们建立了决定系数（R2）等5个评价指标来评价模型的性能。结果表明，KOA-LSB模型预测能力最好，R²值为0.98064，能较准确地预测储层温度。此外，为了更深入地了解储层温度与各种输入特征值之间的关系，采用Shapely Additive explanation （SHAP）分析对机器学习结果进行可解释性分析。结果表明：SiO2对储层温度的影响最大，pH对储层温度的影响最小；本研究不仅提出了一种新颖的机器学习方法，而且对机器学习结果进行了可解释性分析，为地热专业人员提供了可靠的模型选择工具，同时增强了他们对机器学习的信心，促进了对地热资源的更好理解。

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引用次数: 0

Influence of evaluation methods on mechanical properties of cement under thermal cycling: A comparative study between small-scale samples and full-scale annular systems 热循环条件下评价方法对水泥力学性能的影响：小尺寸样品与全尺寸环空体系的对比研究

IF 3.9 2区工程技术 Q3 ENERGY & FUELS

Geothermics

Pub Date : 2026-01-24 DOI: 10.1016/j.geothermics.2026.103608

Niantao Zhou , Hong Zhang , Yuan Jiajie , Yuhan Pang , Fuping Xiao , Yuanhua Lin , Kuanhai Deng , Junping Zhou , Qiqoping Liu

The cement sheath integrity in geothermal wells is prone to damage under ultra-high temperature thermal cycling induced by periodic cold water injection and steam extraction, posing critical safety risks such as annular pressure and wellbore leakage. Based on the typical working conditions in geothermal wells, a high temperature kettle is developed to perform thermal cycling tests on bulk cement samples in a saturated environment, while a full-scale experimental device of the "Φ139.7 mm production casing-cement sheath-Φ244.5 mm intermediate casing" (PC-CS-IC) system is used for evaluating the cement sheath under realistic wellbore conditions. Mechanical property tests are performed after thermal cycling (25°C∼150°C and 25°C∼250°C), by which the behavior of bulk cement samples and cement sheaths is compared, and additional thermal damage induced by casing-cement interface thermal stress is quantified. The results show that thermal cycling induces a non-monotonic evolution in mechanical properties: the uniaxial compressive strength (UCS) and elastic modulus of both specimens first increase and then decrease with increasing cycles, while peak axial strain decreases monotonically. Notably, after the same thermal cycling, the UCS, elastic modulus, and peak axial strain of the cement sheath are 18%∼32%, 15%∼28%, and 16%∼22% lower than those of the bulk cement samples, respectively. This discrepancy is attributed to additional thermal stress at the casing-cement interface, arising from mismatched thermal expansion between casing steel and cement, which accelerates crack propagation in the cement sheath. The findings provide critical experimental data for optimizing geothermal well cementing designs, emphasizing the necessity of annular system evaluations to ensure long-term wellbore integrity.

在周期性冷水注汽引起的超高温热循环下，地热井水泥环完整性容易受到破坏，存在环空压力、井筒泄漏等重大安全隐患。根据地热井的典型工况，研制了高温釜，可在饱和环境下对大量水泥样品进行热循环测试，并利用“Φ139.7 mm生产套管-水泥环-Φ244.5 mm中间套管”（PC-CS-IC）系统的全尺寸实验装置，对水泥环在实际井眼条件下进行评估。在热循环（25°C ~ 150°C和25°C ~ 250°C）后进行力学性能测试，通过该测试比较了散装水泥样品和水泥护套的行为，并量化了套管-水泥界面热应力引起的额外热损伤。结果表明：热循环引起了两种试样力学性能的非单调演化：随着循环次数的增加，两种试样的单轴抗压强度和弹性模量均呈现先增大后减小的趋势，而峰值轴向应变呈单调减小趋势；值得注意的是，经过相同的热循环后，水泥环的UCS、弹性模量和峰值轴向应变分别比散装水泥样品低18% ~ 32%、15% ~ 28%和16% ~ 22%。这种差异是由于套管与水泥之间不匹配的热膨胀导致套管与水泥界面产生额外的热应力，从而加速了水泥环中的裂缝扩展。研究结果为优化地热井固井设计提供了关键的实验数据，强调了环空系统评估的必要性，以确保井筒的长期完整性。

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引用次数: 0

Geological and geochemical characteristics of the non-volcanic geothermal system in Surat Thani area, southern Thailand 泰国南部素叻他尼地区非火山地热系统地质地球化学特征

IF 3.9 2区工程技术 Q3 ENERGY & FUELS

Geothermics

Pub Date : 2026-01-23 DOI: 10.1016/j.geothermics.2026.103607

Pitsanupong Kanjanapayont , Panupong Kongpet , Petchploy Ninsuwan , Sorawit Duangkhun , Rungroj Arjwech

The approximately 30 hot springs in southern Thailand including Surat Thani area are significantly influenced by the Khlong Marui fault. Water samples were collected throughout the Surat Thani area and subjected to geochemical and stable isotope analysis. The highest water temperature recorded at the hot spring was 69 °C. The geochemical analysis revealed that the water is widely composed of sodium chloride, calcium sulfate, calcium bicarbonate, and sodium bicarbonate. However, stable isotope analysis and the comparison of linear equation data with atmospheric water and samples from Surat Thani area suggest that the water in this hot spring system primarily originates from local meteoric water. Additionally, this study analyzed rare earth elements to explore the interactions between the water and surrounding rock, revealing inconsistencies with the granite rocks in the area. A geophysical assessment employing 2D electrical resistivity tomography (ERT) was performed at the Rattana Kosai hot spring in the central part of the Surat Thani area. It reveals distinct NE-SW fracture patterns along with pressurized aquifers that significantly impact flow. Particularly, the prominent NE-SW fracture zones play a crucial role in groundwater confinement and hot water emergence. Integration of 2D ERT analysis with reliable data sources shows that these NE-SW fracture patterns align with the Khlong Marui fault, which may promote shallow reservoirs and hot spring formation in Surat Thani area. The presence of our geophysical and geochemical data suggests that main faults may provide pathways for the meteoric and ocean water to flow deeper to contact the heat source before flowing back, forming the deep reservoirs near heat sources and shallow reservoirs near to the surface.

包括素叻他尼地区在内的泰国南部约有30个温泉受到Khlong Marui断层的显著影响。在整个素叻他尼地区收集了水样，并进行了地球化学和稳定同位素分析。该温泉的最高水温为69°C。地球化学分析表明，水主要由氯化钠、硫酸钙、碳酸氢钙和碳酸氢钠组成。然而，稳定同位素分析和线性方程数据与大气水和素叻他尼地区样品的比较表明，该温泉系统的水主要来自当地的大气水。此外，本研究还分析了稀土元素，探索了水与围岩的相互作用，揭示了与该地区花岗岩的不一致。利用二维电阻率层析成像（ERT）对素叻他尼地区中部的Rattana Kosai温泉进行了地球物理评估。它揭示了明显的NE-SW断裂模式，以及显著影响流动的承压含水层。其中，NE-SW断裂带对地下水封闭和热水涌现起着至关重要的作用。二维ERT分析与可靠数据来源相结合表明，这些NE-SW断裂模式与Khlong Marui断裂一致，可能促进了素叻他尼地区浅层储层和温泉形成。地球物理和地球化学数据表明，主断层可能为大气和海水向深部流动提供了接触热源再回流的通道，形成了靠近热源的深层储层和靠近地表的浅层储层。

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引用次数: 0

Evaluation of multiphase flow models for wellbore flow characterization in geothermal wells 地热井井筒流动特征多相流模型评价

IF 3.9 2区工程技术 Q3 ENERGY & FUELS

Geothermics

Pub Date : 2026-01-23 DOI: 10.1016/j.geothermics.2026.103609

Orkhan Khankishiyev , Hamidreza Karami , Fatemeh Karbalaeisaleh

Geothermal energy extraction involves complex multiphase flow within downhole tubulars. Efficient fluid flow management is pivotal for maximizing energy recovery and ensuring safe operations in geothermal energy systems. Particularly, accurate characterization of multiphase flow, comprising water, steam, and gaseous components, is critical for optimizing geothermal power generation. However, measurement uncertainty and maintenance challenges impede the precise monitoring of flow rates and composition in harsh geothermal environments.

This study addresses the imperative need for improved flow modeling in geothermal wells by evaluating various modeling techniques. The primary goal of this study is to develop an experimental dataset investigating the effect of temperature on pressure gradient and liquid holdup in vertical air-water slug flows. The second goal is to evaluate the predictive accuracy of two wellbore flow simulators widely used in the oil and gas industry, OLGA and TUFFP, in modeling such flows. These models offer a cost-effective and accurate alternative to conventional flow meters, particularly for multiphase flows. The proposed study evaluates empirical correlations and mechanistic models, particularly for air-water flow in the low to moderate temperature range. A 50.8 mm-ID, 7.6 m-tall vertical flow loop was operated at 25, 60, and 80 °C with liquid superficial velocities from 0.006 to 0.30 m s⁻¹ and gas superficial velocities from 0.6 to 9.1 m s⁻¹, yielding 214 steady slug-flow tests. Differential-pressure and temperature transducers provided liquid-holdup and pressure-gradient data with quantified uncertainties, while high-speed videos documented the prevailing multiphase flow regimes.

Model predictions obtained from OLGA HD 2022.1 and TUFFP Unified 2015 were compared with the experimental results. The analysis identifies the property adjustments and holdup closures required for each model to reproduce the observed pressure and holdup trends under moderate-temperature water–air conditions, thereby demonstrating how calibrated multiphase models can replace intrusive flow-metering techniques in geothermal wells and informing future extensions to higher-temperature and flashing regimes. By advancing flow characterization capabilities, this research contributes to the broader objective of transitioning toward a renewable energy landscape.

地热能开采涉及复杂的井下管内多相流动。高效的流体流动管理对于最大限度地提高地热能源采收率和确保地热能源系统的安全运行至关重要。特别是，多相流（包括水、蒸汽和气体成分）的准确表征对于优化地热发电至关重要。然而，测量的不确定性和维护方面的挑战阻碍了在恶劣的地热环境中精确监测流量和成分。本研究通过评价各种模拟技术，解决了改进地热井流动模拟的迫切需要。本研究的主要目标是建立一个实验数据集，研究温度对垂直空气-水段塞流中压力梯度和含液率的影响。第二个目标是评估在油气行业中广泛使用的两种井筒流动模拟器OLGA和TUFFP在模拟此类流动时的预测精度。这些模型提供了一个具有成本效益和准确的替代传统流量计，特别是多相流。提出的研究评估了经验相关性和机制模型，特别是在低至中等温度范围内的空气-水流动。一个直径50.8毫米，高7.6米的垂直流环在25°，60°和80°C下运行，液体表面速度从0.006到0.30米秒（⁻¹），气体表面速度从0.6到9.1米秒（⁻¹），进行了214次稳定的段塞流测试。压差和温度传感器提供了具有量化不确定性的液含率和压力梯度数据，而高速视频记录了主要的多相流状态。将OLGA HD 2022.1和TUFFP Unified 2015的模型预测结果与实验结果进行了比较。分析确定了每个模型在中温水-空气条件下再现所观察到的压力和含率趋势所需的属性调整和含率关闭，从而展示了校准的多相模型如何取代地热井中的侵入式流量测量技术，并为未来扩展到更高温度和喷射状态提供了信息。通过提高流量表征能力，本研究有助于实现向可再生能源景观过渡的更广泛目标。

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引用次数: 0

Analysis of hydrochemical characteristics and geothermal genesis mechanism of the Zhantian-Huitong geothermal belt, Ningdu County 宁都战天—会通地热带水化学特征及地热成因机制分析

IF 3.9 2区工程技术 Q3 ENERGY & FUELS

Geothermics

Pub Date : 2026-01-23 DOI: 10.1016/j.geothermics.2026.103613

Binghong Fan , Ximin Bai , Hailong Ye , Gongxin Chen , Yanyan Li , Ziqi Zeng , Wei Chen

Ningdu County is an important geothermal rich area in Jiangxi Province, with superior resource endowment. Previous studies have mostly focused on single geothermal fields with high exploration degree and temperature. There is a lack of systematicness in the research on the regional and overall spatial distribution characteristics, evolution laws and deep genesis mechanisms of geothermal water chemistry. This paper focuses on the Ningdu Zhantian-Huitong geothermal area, collecting and analyzing 23 groups of geothermal water samples, 1 group of surface water samples, 2 groups of cold spring water samples, and 11 groups of δD and δ¹⁸O isotope data. By comprehensively applying methods such as water chemistry analysis, stable isotopes, and geothermal temperature estimation, The chemical characteristics and component evolution of geothermal water, isotopic characteristics, estimation of heat storage temperature, sources and genesis mechanisms of geothermal water were systematically studied. The results show that the geothermal resources in the area are controlled by the northeast fault structure. The water chemical types are HCO₃·SO₄-Na and SO₄·HCO₃-Na types, and the recharge source is atmospheric precipitation at an elevation of 379-521m. The proportion of cold water mixed in is as high as 70% to 89%. It is estimated that the shallow heat storage temperature is 89 to 152°C, the deep heat storage temperature is 219 to 250°C, and the circulation depth is 2377 to 7743 meters. The genesis mechanism of geothermal water, which is "fracture channel conduction - dual heat source heating - water-rock reaction - cold and hot water mixing", has been revealed. The research results can provide a scientific basis for the heating and storage expansion of geothermal fields in the area and the exploration and development of concealed geothermal resources.

宁都县是江西省重要的地热富集区，资源禀赋优越。以往的研究多集中在勘探程度高、温度高的单一地热田。地热水化学的区域和整体空间分布特征、演化规律及深层成因机制研究缺乏系统性。本文以宁都战天—会通地热区为研究对象，采集分析了23组地热水样品、1组地表水样品、2组冷泉样品以及11组δD和δ18O同位素数据。综合运用水化学分析、稳定同位素、地温估算等方法，系统研究了地热水的化学特征及成分演化、同位素特征、储热温度估算、地热水的来源及成因机制。结果表明，区内地热资源受东北断裂构造控制。水化学类型为HCO3·SO4- na型和SO4·HCO3- na型，补给源为海拔379 ~ 521m的大气降水。冷水掺入比例高达70% ~ 89%。估算浅层蓄热温度89 ~ 152℃，深层蓄热温度219 ~ 250℃，循环深度2377 ~ 7743米。揭示了地热水“裂缝通道传导-双热源加热-水岩反应-冷热水混合”的成因机制。研究成果可为区内地热田的采暖蓄热扩展及隐伏地热资源的勘探开发提供科学依据。

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