Geothermics最新文献_第4页

Performance analysis and geometric evaluation of galvanized T- and Y-Shapes for earth-air heat exchangers using constructal design 基于结构设计的地-空气热交换器镀锌T型和y型的性能分析和几何评价

IF 3.9 2区工程技术 Q3 ENERGY & FUELS

Geothermics

Pub Date : 2026-03-01 Epub Date: 2026-01-03 DOI: 10.1016/j.geothermics.2025.103595

Ana M.B. Domingues , Andre L. Razera , Jairo V.A. Ramalho , Michel K. Rodrigues , Honório J. Fernando , Liércio A. Isoldi , Elizaldo D. dos Santos

This study presents a numerical investigation of the performance of Earth-Air Heat Exchanger (EAHE) systems equipped with galvanized structures surrounding the duct. Two geometric configurations (T- and Y-shaped) are evaluated using the Constructal Design method combined with the Exhaustive Search technique. The analysis considers the EAHE thermal potential (TP_EAHE) and the maximum annual efficiency (θ_max), along with a multi-objective assessment based on the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS), in which TP_EAHE is treated as a benefit criterion and installation depth as a cost criterion. The results indicate that intermediate installation depths (between 3.7 m and 5.0 m) provide better thermal performance, while deeper configurations do not necessarily result in higher TP_EAHE values. The T-shaped geometry with a balanced proportion between the vertical and horizontal branches, and the Y-shaped geometry with a branching angle of 140 degrees, exhibited superior performance, with improvements above 10% and 5%, respectively, compared to the least favorable geometries. The optimized Y-shaped configuration reached θ_max = 72.0%, achieving a 66.3% gain compared to a conventional case (without galvanized material). The multi-objective analysis demonstrated that there is no universally optimal geometry, but rather a set of effective solutions that emerge depending on the priorities assigned to the system's objectives.

本文研究了在风管周围配置镀锌结构的地-空气热交换器（EAHE）系统的性能。采用结构设计方法结合穷举搜索技术对两种几何构型（T形和y形）进行了评价。该分析考虑了EAHE热势（TPEAHE）和最大年效率（θmax），以及基于理想解决方案相似性偏好排序技术（TOPSIS）的多目标评估，其中TPEAHE被视为效益标准，安装深度被视为成本标准。结果表明，中间安装深度（3.7 m至5.0 m）可以提供更好的热性能，而更深的配置并不一定会导致更高的TPEAHE值。垂直和水平分支比例平衡的t形几何结构和分支角度为140度的y形几何结构表现出优异的性能，分别比最差的几何结构提高了10%和5%以上。优化的y形结构达到θmax = 72.0%，与传统情况（没有镀锌材料）相比，获得66.3%的增益。多目标分析表明，没有普遍最优的几何形状，而是根据分配给系统目标的优先级出现的一组有效解决方案。

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引用次数: 0

From Outcrop to Groundwater Flow: The Impact of Overlooked Heterogeneity on Advective Transport in Lower Triassic Sandstones, Eastern France 从露头到地下水流动：被忽视的非均质性对法国东部下三叠统砂岩平流输运的影响

IF 3.9 2区工程技术 Q3 ENERGY & FUELS

Geothermics

Pub Date : 2026-03-01 Epub Date: 2025-12-29 DOI: 10.1016/j.geothermics.2025.103581

Lucas Bofill , Gerhard Schäfer , Guilherme Bozetti , Jean-François Ghienne , Mathieu Schuster

Sandstone aquifers lacking mudstone interbeds are often considered homogeneous. However, depositional processes and diagenesis can generate significant permeability contrasts without notable variations in granulometry. Capturing this heterogeneity in flow models is essential but challenging. Outcrop studies provide valuable analogues for subsurface conditions, revealing sedimentary architectures and facies distributions not observable from borehole data alone. This study focuses on the Lower Grès Vosgien formation in eastern France, an important aquifer hosting lithium-rich geothermal brines in the Upper Rhine Graben, deposited by braided fluvial and aeolian systems during the Lower Triassic. This work aims to evaluate the influence of decimetre- to metre-scale sandstone features on advective transport modelling, through a two-dimensional conceptual model developed using a digital outcrop model and sedimentary facies analysis. Six progressively simplified hydrostratigraphic models are tested to assess how heterogeneity and its representation affect particle residence times, breakthrough curves, longitudinal macrodispersivity, and upscaled anisotropy. Results indicate that distinguishing fluvial- and aeolian-related sandstones significantly influences both horizontal and vertical advective flow. Failure to discretise individual fluvial facies and reliance on deterministic hydraulic conductivity values led to the underestimation of preferential flow pathways, delaying the prediction of first particle arrivals. Moreover, the discretisation between fluvial and aeolian-related deposits significantly affects macrodispersion results and yields considerable anisotropy when the conceptual model is upscaled. The strong coupling between advective flow with heat transfer and solute transport underscores the critical role of the observed sedimentary heterogeneity on the accurate understanding of lithium-rich geothermal brines circulation in the matrix porosity of the Lower Triassic sedimentary successions in the Upper Rhine Graben reservoirs.

缺乏泥岩互层的砂岩含水层通常被认为是均匀的。然而，沉积过程和成岩作用可以产生显著的渗透率对比，而粒度变化不显著。在流模型中捕获这种异质性是必要的，但也是具有挑战性的。露头研究为地下条件提供了有价值的类似物，揭示了仅凭钻孔数据无法观察到的沉积结构和相分布。本研究以法国东部的下gr Vosgien组为研究对象，该组是上莱茵地堑中富含锂地热盐水的重要含水层，由辫状河和风成体系在下三叠世沉积而成。这项工作旨在通过使用数字露头模型和沉积相分析开发的二维概念模型，评估分米至米尺度砂岩特征对平流输运建模的影响。测试了六种逐步简化的水文地层模型，以评估非均质性及其表征如何影响颗粒停留时间、突破曲线、纵向宏观分散性和大尺度各向异性。结果表明，河流和风成相关砂岩的区分对水平和垂直平流都有显著影响。未能离散单个河流相和依赖确定性的水力导率值导致低估了优先流动路径，延迟了第一次颗粒到达的预测。此外，当概念模型扩大时，河流沉积和风成沉积之间的离散化显著影响宏观离散结果，并产生相当大的各向异性。平流换热与溶质输运之间的强耦合凸显了沉积非均质性对准确理解上莱茵地陷下三叠统储层基质孔隙中富锂地热盐水循环的重要作用。

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引用次数: 0

Machine learning-based assessment of medium-deep geothermal energy potential in five chinese cities 基于机器学习的中国五个城市中深层地热能潜力评估

IF 3.9 2区工程技术 Q3 ENERGY & FUELS

Geothermics

Pub Date : 2026-03-01 Epub Date: 2025-12-26 DOI: 10.1016/j.geothermics.2025.103578

Guosheng Jia, Jianke Hao, Xiaofeng Peng, Pei Wang, Zhibin Zhang, Meng Zhang, Liwen Jin

The transition toward sustainable building heating is vital for achieving carbon neutrality. Medium-deep borehole heat exchanger (BHE) systems provide a promising geothermal solution, but large-scale planning is hindered by the high computational demand of traditional simulations for performance prediction across diverse geologies. This study integrates machine learning (ML) algorithms with a validated finite-volume model to develop an efficient framework for evaluating the long-term thermal performance and potential of BHEs. Focusing on five major Chinese cities (Hebei, Tianjin, Shandong, Henan, and Shaanxi), the framework analyzes the impact of key geological and operating parameters (depth: 2000–3000 m; flow rate: 20–40 m³/h; inlet temperature: 5–20 °C). Among three ML algorithms—Levenberg-Marquardt (LM), Bayesian Regularization (BR), and Quantized Conjugate Gradient (QCG)—the LM algorithm achieved superior accuracy (MSE = 3.0261, R = 0.99965) and robustness against overfitting. Regional analysis highlights the crucial influence of local geology. Henan exhibits the highest heat extraction (235.5 kW) with moderate 10-year decay (5.0 %), while Shaanxi shows the steepest decline. Economically, geothermal deployment can reduce heating costs by 60–95 % and CO₂ emissions by 73–89 % compared to conventional coal systems. This ML-driven framework provides rapid, data-informed decision-making for low-carbon heating investment and geothermal integration in sustainable development.

向可持续建筑供暖的过渡对于实现碳中和至关重要。中深钻孔热交换器（BHE）系统提供了一种很有前途的地热解决方案，但由于传统模拟在不同地质条件下的性能预测的高计算需求，阻碍了大规模规划。本研究将机器学习（ML）算法与经过验证的有限体积模型相结合，开发了一个有效的框架，用于评估BHEs的长期热性能和潜力。该框架以中国5个主要城市（河北、天津、山东、河南和陕西）为研究对象，分析了关键地质和运行参数（深度2000-3000 m，流量20-40 m³/h，进口温度5-20℃）的影响。在levenberg - marquardt （LM）、Bayesian Regularization （BR）和Quantized Conjugate Gradient （QCG）三种ML算法中，LM算法具有较好的准确率（MSE = 3.0261, R = 0.99965）和抗过拟合的鲁棒性。区域分析强调了地方地质的重要影响。河南的抽热量最高（235.5 kW）， 10年衰减幅度中等（5.0%），陕西的衰减幅度最大。从经济上讲，与传统的煤炭系统相比，地热部署可以降低60 - 95%的供暖成本和73 - 89%的二氧化碳排放量。这个机器学习驱动的框架为可持续发展中的低碳供暖投资和地热整合提供了快速、有数据依据的决策。

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引用次数: 0

Classification of closed-loop GCHP suitability via governing mechanism of hydrogeological attributes: Case Research in Karstic Terrain, Guiyang, China 基于水文地质属性控制机制的闭环GCHP适宜性分类——以贵阳岩溶地形为例

IF 3.9 2区工程技术 Q3 ENERGY & FUELS

Geothermics

Pub Date : 2026-03-01 Epub Date: 2025-12-04 DOI: 10.1016/j.geothermics.2025.103547

Yi Liu , Peng Pei , Xiaolin Tian

The suitability of closed-loop ground-coupled heat pump (GCHP) was evaluated and classified in the urban area of Guiyang, China, a typical karstic terrain with complex hydrogeological conditions in pure carbonate rocks, interbedded carbonate-clastic rocks, and fissures. The classification task investigated and emphasized the controlling mechanism of site-specified spatial variation and seasonal fluctuation of groundwater flow on borehole heat transfer ability, ground thermal properties and recoverability from thermal imbalance. Within an area of 2525.4 km², it delineated 9 abundant resource areas (16.2 % of the total area), 8 moderate resource areas (53.2 %), and 7 limited resource areas (30.6 %). The framework is adaptable to other regions for zoning and planning shallow geothermal energy exploitation. Successful application requires regional geological structural and hydrogeological information as input, and users’ expertise to identify water conduits and aquifers, and professional judgment regarding the relative advantages of hydrogeological and thermal conditions in a given area. The framework can provide more scientifically round and accurate guide for suitability zoning, permitting and allocation of shallow geothermal energy resources in complex hydrogeological settings.

在纯碳酸盐岩、碳酸盐岩-碎屑岩互层、裂隙发育、水文地质条件复杂的典型岩溶地形中，对闭环地耦合热泵（GCHP）的适宜性进行评价和分类。该分类任务研究并强调了地表水流量的定点空间变化和季节波动对钻孔换热能力、地表水热物性和热平衡恢复能力的控制机制。在2525.4 km2范围内，圈定了资源丰富区9个（占总面积的16.2%），资源中等区8个（占总面积的53.2%），资源有限区7个（占总面积的30.6%）。该框架适用于其他地区浅层地热能开发分区和规划。成功的应用需要区域地质构造和水文地质信息作为输入，以及用户识别水管和含水层的专业知识，以及对特定地区水文地质和热条件相对优势的专业判断。该框架可为复杂水文地质环境下浅层地热能资源适宜性区划、许可和配置提供更为科学、全面和准确的指导。

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引用次数: 0

Improving borehole fracture characterization using oriented sidewall cores for geothermal assessment – an example in central New York State USA 利用定向侧壁岩心改进井眼裂缝特征，用于地热评价——以美国纽约州中部为例

IF 3.9 2区工程技术 Q3 ENERGY & FUELS

Geothermics

Pub Date : 2026-03-01 Epub Date: 2026-01-20 DOI: 10.1016/j.geothermics.2025.103589

Sean A. Fulcher , Teresa E. Jordan , Stephen E. Laubach , Sara J. Elliott , Valeria Nogales Herrera

In New York State and Pennsylvania, USA, Precambrian metamorphic and intrusive rocks and Cambrian to Lower Ordovician sedimentary rocks are reservoir targets for deep direct-use geothermal development. Evaluation of natural fractures and structures in the potential reservoir units at the Cornell University Borehole Observatory site was conducted through cross-scale evaluation of oriented sidewall cores, borehole image (BHI), and far-field acoustic survey data. Oriented sidewall cores in the basement complex (Cayuta Formation) reveal metasediments containing foliations, lineations, mineral-filled fractures, and breccia intervals. Basement sidewall core fracture data aid identification of fractures in BHI surveys riddled with borehole breakouts. In contrast, sidewall and image log data for the Cambrian-Ordovician sedimentary section show that open fractures are present and allow orientation and abundance to be estimated. At various depths sandstone and dolostone sidewall cores contain quartz-filled or carbonate-filled bed-normal and -parallel microfractures. Four subvertical microfracture sets, formed sequentially, strike NW-SE (F1), NE-SW (F2), N-S (F3), and WSW-ENE (F4). Microfracture set orientations F1, F2, and F4 match interpretations of acoustic fracture anomalies (open fractures) located tens of meters from the wellbore. In the uppermost Galway Formation sandstone, common microfracture apertures are 0.001 to 0.01 mm. The widest microfractures transition to quartz-lined and bridged open macrofractures. An open vertical macrofracture in Galway sandstone is observed in BHI surveys and a sidewall core, effectively ground-truthing the F4 fracture set. Based on comparison of core fractures with borehole image survey features, differentiation of natural from drilling-induced fractures reveals three sedimentary rock zones of elevated natural fracture frequency.

在美国纽约州和宾夕法尼亚州，前寒武纪变质岩和侵入岩以及寒武系至下奥陶统沉积岩是深层直接利用地热开发的储层目标。通过对定向侧壁岩心、钻孔图像（BHI）和远场声学测量数据进行跨尺度评价，对康奈尔大学钻孔观测站潜在储层单元中的天然裂缝和结构进行了评价。基底杂岩（Cayuta组）的定向侧壁岩心显示出含有片理、线理、含矿物裂缝和角砾岩层的变质沉积物。基底侧壁岩心裂缝数据有助于识别井眼突出的BHI调查中的裂缝。相比之下，寒武-奥陶系沉积剖面的侧壁和成像测井资料显示，裂缝存在，可以估计裂缝的方向和丰度。在不同深度的砂岩和白云岩侧壁岩心中含有石英充填或碳酸盐岩充填的层向和平行微裂缝。四个亚垂直微裂缝组依次形成，走向NW-SE （F1）、NE-SW （F2）、N-S （F3）和WSW-ENE （F4）。微裂缝集方向F1、F2和F4与距离井筒数十米的声波裂缝异常（张开裂缝）的解释相匹配。在最上层的Galway组砂岩中，常见的微裂缝孔径为0.001 ~ 0.01 mm。最宽的微裂缝转变为石英衬砌和桥接的开放大裂缝。在BHI调查和侧壁岩心中观察到Galway砂岩中有一条开放的垂直大裂缝，有效地对F4裂缝集进行了地面验证。通过岩心裂缝与钻孔图像测量特征的对比，对天然裂缝与钻井裂缝进行了区分，揭示了天然裂缝频率升高的3个沉积岩带。

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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 : 2026-03-01 Epub 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

Construction of a medium-deep geothermal storage system: Case study of the SKEWS MD-BTES demosite 中深层地热储热系统的建设：以SKEWS MD-BTES花岗岩为例

IF 3.9 2区工程技术 Q3 ENERGY & FUELS

Geothermics

Pub Date : 2026-03-01 Epub Date: 2025-12-18 DOI: 10.1016/j.geothermics.2025.103579

Matthias Krusemark , Lukas Seib , Hung Pham , Ingo Sass

The global energy transition toward renewable resources poses particular challenges in the heating sector, where a seasonal mismatch between heat demand and supply remains a critical obstacle. Medium-deep borehole thermal energy storage systems (MD-BTES), installed at depths of 400–1000 m, offer large subsurface storage capacities while avoiding the high costs associated with deep geothermal drilling. To date, the benefits of MD-BTES have been demonstrated primarily through modelling studies, with limited empirical validation. Here, we report the construction and commissioning of the first MD-BTES demonstration site at the Lichtwiese Campus in Darmstadt, Germany. In 2022–2023, three 750 m deep borehole heat exchangers (BHE) were installed in a triangular layout with 8.6 m spacing. When expanded to 37 BHE, with inlet temperatures of 90 °C (summer) and 30 °C (winter), output up to 15 GWh·a^-1 and 3.5 MW is achievable with a recovery efficiency up to 75 % after 5 years of operation. During drilling, unforeseen (hydro-)geological conditions, including fault zones and extensively altered crystalline rocks, required a transition from pneumatic and hydraulic down-the-hole hammer drilling to rotary drilling with clay-polymer fluids. Comparative analysis showed that the pneumatic and hydraulic hammer techniques achieved 2 to 5 times higher rates of penetration relative to rotary drilling. Continuous groundwater monitoring revealed a temporary ecological impact from drilling fluids and intermediate cementations, which dissipated after completion. The drilling operations consumed ∼90,950 L of diesel fuel, corresponding to ∼244 t CO₂ emissions.

These results provide, for the first time, a comprehensive empirical assessment of MD-BTES construction under practical field conditions, enable extended test operations on storage efficiency, and highlighting the need for economically viable vertical and fast drilling technologies for large-scale MD-BTES development.

全球能源向可再生资源的转型给供热行业带来了特别的挑战，供热需求和供应之间的季节性不匹配仍然是一个关键障碍。中深钻孔热能存储系统（MD-BTES）安装在400-1000米的深度，提供了大的地下存储容量，同时避免了与深层地热钻井相关的高成本。迄今为止，MD-BTES的好处主要是通过建模研究证明的，经验验证有限。在这里，我们报告了在德国达姆施塔特的lictwese校区的第一个MD-BTES示范点的建设和调试。在2022-2023年，三个750 m深的井眼热交换器（BHE）以三角形布局安装，间距为8.6 m。当扩展到37 BHE，进口温度为90°C（夏季）和30°C（冬季）时，运行5年后，输出可达15 GWh·a-1和3.5 MW，回收效率高达75%。在钻井过程中，不可预见的（水力）地质条件，包括断层带和广泛改变的结晶岩，需要从气动和液压井下锤式钻井过渡到粘土聚合物流体的旋转钻井。对比分析表明，气动和液压锤技术的钻速是旋转钻井的2 ~ 5倍。连续的地下水监测显示，钻井液和中间胶结物对生态造成了暂时的影响，这些影响在完井后消散。钻井作业消耗了约90950升柴油，相当于排放了约244吨二氧化碳。这些结果首次在实际油田条件下对MD-BTES施工进行了全面的经验评估，实现了对存储效率的扩展测试操作，并强调了大规模MD-BTES开发对经济上可行的垂直和快速钻井技术的需求。

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引用次数: 0

Geothermal potential of karstified Devonian carbonates in NW Germany 德国西北部泥盆纪碳酸盐岩岩溶的地热潜力

IF 3.9 2区工程技术 Q3 ENERGY & FUELS

Geothermics

Pub Date : 2026-03-01 Epub Date: 2025-12-08 DOI: 10.1016/j.geothermics.2025.103552

Manfred Heinelt , Mathias Mueller , Benedikt Ahrens , Mathias Nehler , Katharina Alms , Adrian Immenhauser

The exploration of suitable reservoir rocks for deep geothermal energy in NW Germany focuses on karstified carbonates of Carboniferous and Devonian age. Using a case example from the city of Iserlohn, we demonstrate that these rocks exhibit high thermal yields due to the secondary porosity caused by meteoric (and potentially hypogenic) karstification. Karstified carbonates, if structurally interconnected on a reservoir scale, have the potential to provide significantly higher permeability. We conducted thermo-triaxial cell experiments for depths exceeding 2 km. Our findings indicate that dolostones offer enhanced mechanical integrity and exhibit reduced porosity loss with increasing depth. Visual inspections of µCT scans confirm that karstification results in large, interconnected pores that have been leached. The effective porosity of karstified carbonates reaches 14 %, with measured permeability values in the order of 10⁻¹⁶ m². In terms of porosity and permeability, karstified units can outperform non-karstified ones by up to two orders of magnitude. We conducted heat-in-place modelling using petrophysical laboratory data as input parameters for Monte Carlo simulations. An initial map was created to illustrate the potential geothermal energy stored and to identify areas with the highest energy yield. The estimated potential energy stored in the subsurface is greatest in the southern part of the Iserlohn study area, where the thickness of the Devonian carbonates is at its maximum. This deeper occurrence in the subsurface leads to a significant increase in reservoir temperature. The modelling results indicate a potential energy range for the entire distribution of Devonian carbonates between 87 TJ (P90) and 110 TJ (P10).

德国西北部适合深层地热能的储层主要以石炭系和泥盆系岩溶碳酸盐岩为主。以Iserlohn市为例，我们证明了这些岩石由于大气（和潜在的低成因）岩溶作用引起的次生孔隙而表现出高热产量。如果岩溶盐岩在储层规模上相互连接，则具有显著提高渗透率的潜力。我们进行了深度超过2公里的热三轴电池实验。我们的研究结果表明，随着深度的增加，白云岩的机械完整性增强，孔隙度损失减少。微CT扫描的目视检查证实，岩溶作用导致浸出的大而相互连接的孔隙。碳酸盐岩的有效孔隙度达14%，实测渗透率为10 ~ 16 m²。在孔隙度和渗透率方面，岩溶单元可以比非岩溶单元高出两个数量级。我们使用岩石物理实验室数据作为蒙特卡罗模拟的输入参数，进行了就地热模拟。初步绘制了一张地图，以说明潜在的地热能储存，并确定能源产量最高的地区。Iserlohn研究区南部泥盆纪碳酸盐岩厚度最大，估算的地下储存势能最大。地下较深的分布导致储层温度显著升高。模拟结果表明，整个泥盆纪碳酸盐岩分布的势能范围在87 TJ (P90) ~ 110 TJ （P10）之间。

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引用次数: 0

Development and validation of regression model via machine learning to estimate thermal conductivity and heat flow using igneous rocks from the Dikili-Bergama geothermal region, Western Anatolia 通过机器学习开发和验证回归模型，以估计来自安纳托利亚西部Dikili-Bergama地热区的火成岩的导热系数和热流

IF 3.9 2区工程技术 Q3 ENERGY & FUELS

Geothermics

Pub Date : 2026-03-01 Epub Date: 2025-12-09 DOI: 10.1016/j.geothermics.2025.103567

Tolga Ayzit , Onur Güngör Şahin , Selçuk Erol , Alper Baba

Thermal conductivity is a fundamental parameter that significantly influences the thermal regime of the lithosphere. It plays a crucial role in a variety of geological applications, including geothermal energy exploration, igneous system assessment, and tectonic modeling. In this study, a machine learning approach is used to predict the thermal conductivity of igneous rocks based on the composition of major oxides. A total of 488 samples from different regions of the world were analyzed. The thermal conductivity values ranged from 1.20 to 3.74 Wm⁻¹ K⁻¹ and the mean value was 2.61 Wm⁻¹ K⁻¹. The Random Forest (RF) algorithm was used, resulting in a high coefficient of determination (R² = 0.913 for training and R² = 0.794 for testing) and a root mean square error (RMSE) of 0.112 and 0.179, respectively. Significance analysis of the traits identified SiO₂ (>40 %), Na₂O (>15 %) and Al₂O₃ (>10 %) as the most influential predictors. The study presented results from the Western Anatolia region, where felsic rocks had the highest thermal conductivity (mean = 2.69 Wm⁻¹K⁻¹) compared to mafic (mean = 2.34 Wm⁻¹K⁻¹) and ultramafic rocks (mean = 2.39 Wm⁻¹K⁻¹). In addition, the study evaluated the predictive capabilities of machine learning models for the igneous rocks of the Dikili-Bergama region and compared the results with those of saturated models. Using these data, we calculated heat flow values of up to 400 mWm⁻² under saturated conditions in western Anatolia. These results highlight the value of integrating geochemical data with machine learning to improve geothermal resource exploration and lithospheric modeling.

热导率是影响岩石圈热状态的基本参数。它在地热能勘探、火成岩系统评价和构造模拟等多种地质应用中发挥着至关重要的作用。在这项研究中，基于主要氧化物的组成，使用机器学习方法来预测火成岩的导热性。总共分析了来自世界不同地区的488个样本。热导率为1.20 ~ 3.74 Wm−1 K−1，平均值为2.61 Wm−1 K−1。采用随机森林（Random Forest， RF）算法，具有较高的决定系数（训练R²= 0.913，检验R²= 0.794），均方根误差（RMSE）分别为0.112和0.179。对这些性状的显著性分析发现SiO₂（> 40%）、Na2O （> 15%）和Al₂O₃（> 10%）是最具影响力的预测因子。研究结果来自西部安纳托利亚地区，与基性岩（平均2.34 Wm−¹K−¹）和超基性岩（平均2.39 Wm−¹K−¹）相比，长英质岩的导热系数最高（平均2.69 Wm−¹K−¹）。此外，该研究还评估了机器学习模型对Dikili-Bergama地区火成岩的预测能力，并将结果与饱和模型进行了比较。利用这些数据，我们计算了安纳托利亚西部饱和条件下高达400 mWm−2的热流值。这些结果突出了地球化学数据与机器学习相结合在地热资源勘探和岩石圈建模方面的价值。

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引用次数: 0

Comparison of thermo-mechanical response between the grouted method and ordinary micro steel pipe energy pile under multiple heating and cooling cycles 灌浆法与普通微钢管能源桩在多次加热和冷却循环下的热-力学响应比较

IF 3.9 2区工程技术 Q3 ENERGY & FUELS

Geothermics

Pub Date : 2026-03-01 Epub Date: 2025-12-13 DOI: 10.1016/j.geothermics.2025.103571

Hong Chang , Xing Wu , Zhengheng Gan , Yuan Du , Huicheng Jiang , Zhaoxuan Wang , Ming Ma

As an energy underground structure combining load-bearing and heat exchange capabilities, micro energy pile (MEP) offers unique advantages for geothermal heating compared with conventional energy pile (EP). Despite their potential, micro energy piles (MEP) have received far less attention compared to conventional energy piles (EP). This study presents a comparative analysis of the thermo-mechanical response characteristics of micro grouted steel pipe energy pile (MGSPEP) and micro steel pipe energy pile (MSPEP). The results indicate the influence range of the soil temperature field for both types of piles extends to approximately four times the pile diameter. The heat exchange rate of the MGSPEP ranges from 44.5 to 49.4 W/m, showing no significant difference compared with that of EP. The maximum additional tensile stress and compressive stress of the two piles account for less than 5 % of the tensile and compressive design values of the steel pipe. MGSPEP has a smaller pile and soil relative displacement. The settlement of MGSPEP and MSPEP accounts for 0.4 % D and 1.1 % D of the pile diameter, respectively. The accumulative soil pressure at the pile tip of MSPEP is 1.08 kPa, and MGSPEP accounts for only 28.7 % of MSPEP. The findings of this study provide new insights and references for the structural and energy retrofitting applications of MGSPEP in both existing and newly constructed buildings. This is expected to enhance the sustainability of geothermal energy systems.

微能源桩作为一种集承载和换热于一体的地下能源结构，与传统能源桩相比，具有独特的地热采暖优势。尽管具有潜力，但与传统能源桩相比，微能源桩受到的关注远远不够。对微灌浆钢管能源桩（MGSPEP）和微钢管能源桩（MSPEP）的热-力学响应特性进行了对比分析。结果表明，土温场对两种桩的影响范围均扩大到桩径的4倍左右。MGSPEP的热交换率在44.5 ~ 49.4 W/m之间，与EP的热交换率无显著差异。两桩最大附加拉压应力占钢管拉压设计值的比例小于5%。MGSPEP具有较小的桩土相对位移。MGSPEP和MSPEP的沉降分别占桩径的0.4% D和1.1% D。MSPEP桩端累积土压力为1.08 kPa，仅占MSPEP的28.7%。本研究结果为MGSPEP在既有建筑和新建建筑中的结构和能源改造应用提供了新的见解和参考。预计这将提高地热能源系统的可持续性。

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引用次数: 0