IF 3.5 2区工程技术 Q3 ENERGY & FUELS

Geothermics

Pub Date : 2025-04-24 DOI: 10.1016/j.geothermics.2025.103350

M. Barla, A. Insana, M.R. Alvi

In the very shallow depths of urban areas it is difficult to find natural undisturbed underground thermal conditions because of anthropic interventions. Moreover, these areas are being increasingly used for energy purposes, for example implementing the technology of shallow geothermal systems to provide clean thermal energy and supply the thermal demand of buildings in both winter and summer seasons. The heat exchanged by these types of renewable energy technologies, in particular ground source heat pump systems such as open loop and closed loop ones, in combination with further anthropogenic activities, results in altered thermal regimes in the subsurface. Energy tunnels, which are achieved by thermally activating the tunnel lining, have recently gained attention among closed loop geothermal systems. Therefore, when planning an urban energy tunnel, attention has to be devoted to the initial underground thermal conditions and to the interactions the pre-existing thermal regime will have with the energy tunnel itself. To this aim, the paper outlines a methodological approach which is then applied to a case study in Turin, Italy, where a new metro line is planned. Thermo-hydraulic numerical modelling is adopted to reproduce the thermally disturbed subsurface environment in the study area prior to the energy tunnel’s thermal activation, due to the presence of multiple heat sources (open loop and closed loop systems, underground buildings, car parks and infrastructures), as well as after its commissioning. Results are illustrated in terms of temperature maps and cross sections where the thermally affected zones due to open loop, mainly, and closed loop systems are depicted depending on the operational mode of the shallow geothermal systems. Those results highlight that, when the installation of a new energy tunnel is envisaged, it is necessary to consider the current geothermal exploitation of the area and the operation of neighbouring similar systems.

在城市地区的极浅深处，由于人为干预，很难找到自然的未受干扰的地下热条件。此外，这些地区正越来越多地用于能源目的，例如实施浅层地热系统技术，以提供清洁热能，并在冬季和夏季满足建筑物的热需求。这些类型的可再生能源技术，特别是诸如开环和闭环的地源热泵系统所交换的热量，与进一步的人为活动相结合，导致地下热状态的改变。能量隧道是通过热激活隧道衬砌来实现的，近年来在闭环地热系统中得到了广泛的关注。因此，在规划城市能源隧道时，必须注意初始地下热条件以及预先存在的热状态与能源隧道本身的相互作用。为此，本文概述了一种方法学方法，然后将其应用于意大利都灵的一个案例研究，那里正在规划一条新的地铁线路。采用热水力数值模拟再现研究区由于多个热源（开环和闭环系统、地下建筑、停车场和基础设施）的存在，在能量隧道热激活之前，以及在其调试之后的热扰动地下环境。结果用温度图和横截面来说明，其中主要由开环和闭环系统引起的热影响区根据浅层地热系统的运行模式进行了描述。这些结果突出表明，在设想安装新的能源隧道时，必须考虑到该地区目前的地热开发情况和邻近类似系统的运作情况。

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引用次数: 0

An improved modeling method using overlapping meshes for geothermal wellbore simulation 一种改进的叠合网格地热井筒模拟方法

IF 3.5 2区工程技术 Q3 ENERGY & FUELS

Geothermics

Pub Date : 2025-04-23 DOI: 10.1016/j.geothermics.2025.103345

Peng Hong , Fuyan Zhao , Haiyan Lei , Guiling Wang , Chuanshan Dai

Since temperature and pressure disturbances in geothermal reservoirs are mainly caused by production and injection activities through wellbores, establishing an accurate wellbore model is crucial. However, due to significant size discrepancies between wellbores and reservoirs, accurately resolving the wellbore geometry requires a large number of mesh cells, which seriously reduces computational efficiency. A commonly used method to reduce the mesh cell number is simplifying the wellbore geometry as a point (in 2D) or a line (in 3D). However, existing modeling methods for this simplified wellbore geometry introduce additional errors. To improve calculation accuracy without reducing computational efficiency, we propose an overlapping mesh modeling method, which incorporates one overlapping cell for each wellbore, enabling the wellbore geometry to be considered without impacting the reservoir mesh generation. The wellbore cell can exchange mass and energy with the reservoir cells it covers, ensuring that the temperature and pressure disturbances caused by wells can be simulated accurately. Four benchmark cases were used to verify the present method. The results show that, compared to existing simplified wellbore modeling methods, the present method reduces hydraulic head errors by 1 to 2 m and temperature errors by 1 to 2 ℃ in the vicinity of the wellbore, while the additional computational cost is negligible.

由于地热储层的温度和压力扰动主要是由井筒内的生产和注入活动引起的，因此建立准确的井筒模型至关重要。然而，由于井眼和油藏之间存在显著的尺寸差异，精确求解井筒几何形状需要大量的网格单元，这严重降低了计算效率。减少网格单元数的一种常用方法是将井筒几何形状简化为一个点（2D）或一条线（3D）。然而，对于这种简化的井筒几何形状，现有的建模方法引入了额外的误差。为了在不降低计算效率的情况下提高计算精度，我们提出了一种重叠网格建模方法，该方法为每个井眼包含一个重叠单元，从而在不影响油藏网格生成的情况下考虑井眼几何形状。井筒单元可以与其覆盖的储层单元交换质量和能量，确保可以准确模拟井引起的温度和压力干扰。用四个基准案例验证了该方法的有效性。结果表明，与现有简化的井筒建模方法相比，该方法可将井筒附近水头误差减小1 ~ 2 m，温度误差减小1 ~ 2℃，而额外的计算成本可以忽略不计。

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引用次数: 0

Spatial distribution of mercury in geothermal springs and its correlation with tectonic setting in the Bayan Har block of Tibetan Plateau, China 青藏高原巴颜喀尔地块地热泉中汞的空间分布及其与构造背景的相关性

IF 3.5 2区工程技术 Q3 ENERGY & FUELS

Geothermics

Pub Date : 2025-04-22 DOI: 10.1016/j.geothermics.2025.103351

Ke Zhang , Hongyi He , Ying Li , Chang Lu , Zihan Gao , Zhaofei Liu , Zhi Chen

Mercury (Hg) serves as a pivotal tracer in geothermal systems, elucidating both deep lithospheric processes and surficial environmental dynamics. Constraining the sources and distribution of Hg in hot springs as well as its behavior is essential for unraveling subsurface fluid-rock interactions and assessing potential environmental risks. However, the distribution patterns of Hg in geothermal systems, particularly in tectonically active regions, remain poorly understood. This research investigated the distribution of thermal Hg across the Baryan Har block within the Tibet Plateau, a region featured by intense tectonic activity. Through integrated geochemical analysis of 58 springs, we revealed spatial variations in dissolved Hg concentrations (0.51∼50.66 ng/L, with an exceptionally high value of 1100.5 ng/L), exhibiting relatively higher Hg enrichment in the springs along active fault boundaries (44.35±186.99 ng/L) than that in intra-block region (4.16±4.69 ng/L). Geochemical data suggested that non-geological factors (including atmospheric precipitation and anthropogenic activity) and water-rock interactions involving Hg-bearing minerals were not the primary factors influencing the observed Hg distribution. The positive correlation between Hg and chloride concentrations in springs near block boundary fault indicated that deep fluids might be a significant source of Hg. Additionally, the spatial correlation between Hg concentrations, shear strain rates, and heat flow further confirmed the impacts of tectonic regime on the migration and enrichment of Hg. This research underscores the significance of tectonic activity on governing Hg distribution in geothermal systems, providing a better understanding for the geochemical behaviors of Hg in tectonically active regions and its potential environmental implications.

汞（Hg）作为地热系统的关键示踪剂，阐明了深层岩石圈过程和地表环境动力学。控制温泉中汞的来源和分布及其行为对于揭示地下流体-岩石相互作用和评估潜在的环境风险至关重要。然而，汞在地热系统中的分布模式，特别是在构造活跃地区，仍然知之甚少。本文研究了青藏高原内构造活动强烈的巴里安哈尔地块的热汞分布。通过对58条泉水的综合地球化学分析，我们发现了溶解汞浓度的空间变化（0.51 ~ 50.66 ng/L，其中异常值为1100.5 ng/L），表明沿活动断层边界的泉水中汞的富集程度（44.35±186.99 ng/L）高于块内区域（4.16±4.69 ng/L）。地球化学数据表明，非地质因素（包括大气降水和人为活动）和含汞矿物的水岩相互作用不是影响观测到的汞分布的主要因素。在地块边界断裂附近的泉水中，Hg与氯离子浓度呈正相关，表明深部流体可能是重要的Hg来源。此外，Hg浓度、剪切应变速率和热流的空间相关性进一步证实了构造制度对Hg迁移和富集的影响。为构造活动区汞的地球化学行为及其潜在的环境意义提供了更好的认识。

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引用次数: 0

Characterization of real-time thermal response during rupture of hot dry rock under the shock of liquid Nitrogen circulation 液氮循环冲击下干热岩石破裂过程的实时热响应表征

IF 3.5 2区工程技术 Q3 ENERGY & FUELS

Geothermics

Pub Date : 2025-04-22 DOI: 10.1016/j.geothermics.2025.103346

Honghao Yuan , Qiang Sun , Jianjun Hu , Jishi Geng , Yuliang Zhang , Jikun Wang , Mingbo Chi , Ersheng Zha

Circulating liquid nitrogen (LN₂) fracturing technology significantly enhances the remodeling performance of geothermal reservoirs in hot dry rock (HDR). This study examines the real-time thermal response characteristics of hot dry rock subjected to thermal shock from the LN₂ cycle. The dynamic evolution and real-time rupture behavior of internal cracks in HDR under LN₂ cycle impacts at varying heating temperatures are captured using acoustic emission technology. The damage mechanism and crack development process of HDR under the LN₂ cycle shock are discussed. Findings indicate that during the early stage of LN₂ cooling, the extreme temperature differential between the HDR surface and liquid nitrogen induces a sharp increase in thermal stress, resulting in notable damage effects, peak acoustic emission energy counts occur. In the middle and late stages of cooling, acoustic emission activity is minimal at heating temperatures of 200 °C and 300 °C, while at 400 °C, high acoustic emission energy is observed. 300 °C-400 °C is the temperature threshold interval for significant changes in damage characteristics of HDR under heating- LN₂ rapid cooling conditions. Additionally, the cumulative energy of the total number of cycles at 300 °C is 46.2 % higher than at 200 °C, and at 400 °C, it is 186.9 % and 96.2 % higher compared to 200 °C and 300 °C, respectively. The degree of damage to HDR escalates with increasing heating temperature and cycle number. The LN₂ cooling process primarily manifests as shear damage, with small amount of tensile damage occurring at higher heating temperatures.

循环液氮（LN2）压裂技术显著提高了干热岩地热储层的改造性能。本文研究了LN2循环热冲击作用下干热岩石的实时热响应特征。利用声发射技术捕捉了不同加热温度下LN2循环冲击下HDR内部裂纹的动态演化和实时破裂行为。讨论了HDR在LN2循环冲击下的损伤机理和裂纹发展过程。结果表明，在LN2冷却初期，HDR表面与液氮之间的极端温差导致热应力急剧增加，产生显著的损伤效应，声发射能量出现峰值。在冷却中后期，在加热温度为200℃和300℃时，声发射活动最小，而在加热温度为400℃时，声发射能量较高。300℃-400℃是加热- LN2快速冷却条件下HDR损伤特性发生显著变化的温度阈值区间。此外，300℃时总循环次数的累积能量比200℃时高46.2%，400℃时比200℃和300℃时分别高186.9%和96.2%。随着加热温度的升高和循环次数的增加，HDR的破坏程度逐渐增大。LN2冷却过程主要表现为剪切损伤，在较高加热温度下出现少量拉伸损伤。

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引用次数: 0

Circulation process of geothermal fluids and potential assessment of geothermal resources in the Songwe half-graben and Kiejo-Mbaka prospects in southwestern Tanzania: Insight from hydrochemistry and stable isotopes 坦桑尼亚西南部松圭半地堑地热流体循环过程与地热资源潜力评价及Kiejo-Mbaka远景：来自水化学和稳定同位素的启示

IF 3.5 2区工程技术 Q3 ENERGY & FUELS

Geothermics

Pub Date : 2025-04-21 DOI: 10.1016/j.geothermics.2025.103347

Nyora Donald Kobare , Koki Kashiwaya , Katsuaki Koike , Albano Mahecha

The Songwe and Kiejo-Mbaka geothermal prospects in Tanzania's East African Rift System are anticipated to be harnessed for geothermal power generation by 2030. This study examines the geothermal fluids' origin, evolution, and natural geothermal potential through geochemical analyses of stable isotopes, major ions, trace solutes, and fluid–mineral equilibria. Analysis samples were taken from hot, warm and cold springs, rivers, and rainwater from the prospects. The predominant Na and K in the samples suggest advanced chemical reactions composed primarily of ion exchange and calcite dissolution in the geothermal system. Four reservoirs, Songwe-Rambo and Kaguri (Songwe) and Ilwalilo and Kilambo (Kiejo-Mbaka), are identified as fluid upflow zones of geothermal systems. Mineral equilibria modeling reveals two key features: saturation with carbonate minerals like aragonite, dolomite, and calcite, linked to travertine development near discharge zones, and silica saturation, primarily quartz and chalcedony, across varying temperatures, suggesting potential silica deposits. Estimated reservoir temperatures range from 90 to 135 °C (Songwe) to 100–145 °C (Kiejo-Mbaka), based on geothermometry methods. Given flow rates of 0.05–10 L/s and temperature differences of 20.8–145 °C, the geothermal power potential is assessed at 4 MW_th for Songwe and 5 MW_th for Kiejo-Mbaka. The primary source of geothermal fluids is meteoric water, recharged at about 2100 m above sea level, which infiltrates to an average depth of ca. 2000 m, driven by heat sources, before re-emerging at the surface. A conceptual model of the geothermal system over these prospects is developed, enhancing the groundwork for evaluating geothermal resources and planning future exploratory drilling.

坦桑尼亚东非裂谷系统的Songwe和Kiejo-Mbaka地热勘探区预计到2030年将用于地热发电。本文通过稳定同位素、主要离子、微量溶质、流矿平衡等地球化学分析，探讨了地热流体的成因、演化和天然地热潜力。分析样本取自热泉、温泉和冷泉、河流和来自前景的雨水。样品中主要的Na和K表明地热系统中主要由离子交换和方解石溶解组成的高级化学反应。Songwe- rambo和Kaguri （Songwe）和Ilwalilo和Kilambo （kijo - mbaka）四个储层被确定为地热系统的流体上行带。矿物平衡模型揭示了两个关键特征：碳酸盐矿物的饱和度，如文石、白云石和方解石，与排泄带附近的石灰华发育有关；二氧化硅饱和度，主要是石英和玉软石，在不同的温度下，表明潜在的二氧化硅矿床。根据地热测量方法，估计储层温度范围为90 ~ 135℃（Songwe）至100 ~ 145℃（Kiejo-Mbaka）。在流量为0.05 ~ 10 L/s、温差为20.8 ~ 145℃的条件下，Songwe和Kiejo-Mbaka的地热发电潜力分别为4 MWth和5 MWth。地热流体的主要来源是大气水，在海拔2100米左右补给，在热源的驱动下渗入到平均约2000米的深度，然后在地表重新出现。在这些远景区建立了地热系统的概念模型，为评价地热资源和规划未来的勘探钻探奠定了基础。

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引用次数: 0

Thermo-coupled FSI analysis of high-temperature heterogeneity rocks subjected to jet impingement 射流冲击下高温非均质岩石的热耦合FSI分析

IF 3.5 2区工程技术 Q3 ENERGY & FUELS

Geothermics

Pub Date : 2025-04-19 DOI: 10.1016/j.geothermics.2025.103348

Tao Huang , Xianwei Dai , Qingyou Liu , Haiyan Zhu

Jet impingement is an efficient rock breaking method in the development of geological resources. In high-temperature formations, thermal stress induced by the temperature difference interacts with fluid pressure and impact forces, thus further enhancing the efficiency of rock failure. Meanwhile, the inherent heterogeneity of rocks influences stress distribution and failure characteristics of rocks as well. To elucidate this intricate process, a multi-physics coupling model is developed in the present study, in which the finite-discrete-element method (FDEM) and Weibull distribution are employed to describe the mechanical response and heterogeneity of rocks. The evolution of temperature, stress, and crack propagation are computed to reveal rock failure mechanisms under different formation conditions and jet parameters. The findings indicate that increasing jet pressure markedly increases jet velocity, improves heat transfer efficiency, and changes the transition from heat conduction to convective heat transfer. Thereby, greater thermal stress is induced, which is accompanied by the application of increased jet pressure on the rock surface. The combined effects of these two factors result in an initial decrease followed by a subsequent increase in crack length. Although rock temperature has fewer effects on jet velocity, the heat transfer efficiency also increases at elevated temperatures resulting from the variation of temperature differences. Correspondingly, thermal stress and crack length rise continually. Moreover, heightened heterogeneity exacerbates rock damage. In this research, thermal stress exerts pronounced effects on crack length once rock temperature exceeds 200 °C on the whole. However, the heightened rock heterogeneity can lower the critical temperature threshold for the propagation of cracks. The results of this investigation provide an in-depth insight into the rock failure mechanism influenced by multi-physics coupling.

射流冲击是地质资源开发中一种有效的破岩方法。在高温地层中，温差引起的热应力与流体压力和冲击力相互作用，进一步提高了岩石破坏的效率。同时，岩石本身的非均质性也影响着岩石的应力分布和破坏特征。为了解释这一复杂的过程，本文建立了一个多物理场耦合模型，采用有限离散元法（FDEM）和威布尔分布来描述岩石的力学响应和非均质性。计算了温度、应力和裂纹扩展的演化过程，揭示了不同地层条件和射流参数下岩石的破坏机制。研究结果表明，射流压力的增加显著提高了射流速度，提高了换热效率，改变了热传导向对流换热的转变。因此，产生了更大的热应力，并伴随着岩石表面喷射压力的增加。这两个因素的综合作用导致裂纹长度开始减小，随后增加。虽然岩石温度对射流速度的影响较小，但由于温差的变化，在温度升高时传热效率也有所提高。相应的，热应力和裂纹长度不断增大。此外，非均质性的增强加剧了岩石的损伤。在本研究中，当岩石温度总体超过200℃时，热应力对裂纹长度的影响较为明显。然而，岩石非均质性的提高降低了裂纹扩展的临界温度阈值。研究结果为深入了解多物理场耦合影响下的岩石破坏机制提供了依据。

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引用次数: 0

Experimental investigation of mechanical behavior and thermal damage of hot dry rock exposing to different cooling conditions 不同冷却条件下干热岩石力学行为及热损伤试验研究

IF 3.5 2区工程技术 Q3 ENERGY & FUELS

Geothermics

Pub Date : 2025-04-18 DOI: 10.1016/j.geothermics.2025.103332

Zaobao Liu , Yu Sun , Yun Jia , Hanbing Bian , Zhan Yu

The exploration of underground geothermal energy requires investigating the cooling effects on the mechanical behaviors and damage mechanisms of high-temperature granite due to injection-production activities. The present work focuses on the influence of preheating and subsequent cooling treatments on the thermal damage of mechanical behavior/properties of a fine-grained granite, with special attention to the cooling method. The studied granite, drilled from a depth of 2000 m in Sichuan Province, China, was heated from room temperature to 800 °C and cooled by air and water cooling methods. It is observed that the cooling method has an important impact on the mechanical and damage behavior of the studied granite once the pre-heating temperature exceeds 500 °C. The dramatic transition of crack threshold is also observed as a function of temperature and cooling rate. Moreover, the experimental analysis exhibits that thermal conductivity is capable of providing a satisfactory estimation of thermal damage level of granite, compared to P-wave velocity. Finally, the influence of crystal particle sizes on the thermal damage of granite is also performed. Compared to fine-grained (FG) and medium-grained (MG) granites, one observes that during the heating phase, the most important thermal damage is observed in coarse-grained (CG) granites while CG granites are less influenced by the cooling methods. The obtained experimental results and analysis can help understand the mechanical and failure behavior of granite exposed to different cooling regimes encountered in deep geothermal projects.

地下地热能的开发需要研究注采活动对高温花岗岩力学行为和损伤机制的冷却效应。本文主要研究了预热和后续冷却处理对细粒花岗岩力学行为/性能热损伤的影响，特别关注了冷却方法。所研究的花岗岩是从中国四川省2000米深处钻取的，从室温加热到800°C，并通过空气和水冷却方法冷却。研究发现，当预热温度超过500℃时，冷却方式对花岗岩的力学性能和损伤行为有重要影响。裂纹阈值随温度和冷却速率的变化而急剧变化。此外，实验分析表明，与纵波速度相比，导热系数能够提供令人满意的花岗岩热损伤水平估计。最后，研究了晶体粒度对花岗岩热损伤的影响。与细粒（FG）和中粒（MG）花岗岩相比，在加热阶段，粗粒（CG）花岗岩的热损伤最为严重，而粗粒（CG）花岗岩受冷却方式的影响较小。所得的实验结果和分析有助于了解深部地热工程中花岗岩在不同冷却方式下的力学和破坏行为。

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引用次数: 0

An analysis of the accuracy and computational efficiency of the use of one-dimensional fluid models in borehole heat exchangers 分析在钻孔热交换器中使用一维流体模型的准确性和计算效率

IF 3.5 2区工程技术 Q3 ENERGY & FUELS

Geothermics

Pub Date : 2025-04-15 DOI: 10.1016/j.geothermics.2025.103343

A. Holmes, C. Millar, M.F. Lightstone

This paper compares the accuracy of a one-dimensional fluid model to that of a fully three-dimensional model for the simulation of a thermal response test performed on a single borehole heat exchanger. The simplification of the fluid domain within the one-dimensional model allows for reduced computational time while still maintaining an accurate prediction of transient fluid temperature. The model uses a simplified one-dimensional fluid model while solving the full three-dimensional transient heat conduction equations in the borehole heat exchanger and surrounding ground. A symmetry plane is implemented to further reduce the computational effort, and the model and equation adjustments necessary to merge the use of symmetry planes and 1D linear elements along the central plane without loss of model accuracy is explained in detail. The proposed model is compared to a full CFD model and validated using experimental data for a constant heat rate test, commonly known as a thermal response test, to ensure no accuracy is lost due to model adjustments. Additionally, the computation times are compared for each case to quantify the time savings that result from model implementation.

本文比较了一维流体模型与全三维模型在模拟单孔热交换器热响应试验中的精度。一维模型中流体域的简化允许减少计算时间，同时仍然保持对瞬态流体温度的准确预测。该模型采用简化的一维流体模型，求解井内换热器及周围地面的全三维瞬态热传导方程。为了进一步减少计算工作量，实现了对称平面，并详细解释了在不损失模型精度的情况下，将对称平面和沿中心平面的一维线性元素合并使用所需的模型和方程调整。将提出的模型与完整的CFD模型进行比较，并使用恒定热速率测试（通常称为热响应测试）的实验数据进行验证，以确保模型调整不会损失准确性。此外，对每种情况的计算时间进行比较，以量化模型实现所节省的时间。

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引用次数: 0

The characterization of fractures and analysis of hydraulic properties in granite-type hot dry rock reservoirs 花岗岩型干热岩储层裂缝特征及水力特性分析

IF 3.5 2区工程技术 Q3 ENERGY & FUELS

Geothermics

Pub Date : 2025-04-14 DOI: 10.1016/j.geothermics.2025.103342

Yanguang Liu , Yingnan Zhang , Xin Wang , Kai Bian , Haiyan Lei

Hot dry rock (HDR), a widely distributed geothermal resource, holds significant development potential. The geometric characteristics and distribution of the fracture system within the reservoir are crucial, as they directly influence the flow paths and storage capacity of underground fluids. This study establishes a predictive framework for granite-type hot dry rock (HDR) reservoirs in China's Gonghe Basin by integrating field data, stochastic discrete fracture network (DFN) modeling, and geomechanical upscaling. Natural fractures, characterized via imaging logging, cores, and outcrops, exhibit three dominant orientations (NW, NNW, NE) and a power law size distribution. Monte Carlo simulations translated 1D fracture density (P10) into volumetric constraints (P32), enabling 3D DFN construction. Oda-based upscaling revealed permeability anisotropy, with maximum values of 0.268 mD (x-direction), 0.277 mD (y-direction), and 0.135 mD (z-direction), governed by low-dip NE/NW fractures, alongside reduced Young's modulus, Poisson's ratio and localized stress perturbations in fracture-rich zones. Simulated in-situ stresses aligned with field measurements, validating the model. The workflow bridges multi-scale data gaps, offering critical insights for optimizing hydraulic fracturing in low-permeability HDR systems.

干热岩是一种分布广泛的地热资源，具有重要的开发潜力。储层内裂缝系统的几何特征和分布是至关重要的，因为它们直接影响地下流体的流动路径和储存能力。通过综合现场数据、随机离散裂缝网络（DFN）建模和地质力学升级，建立了中国和合盆地花岗岩型热干岩（HDR）储层预测框架。通过成像测井、岩心和露头对天然裂缝进行表征，裂缝表现出三个主要方向（NW、NNW、NE）和幂律尺寸分布。蒙特卡罗模拟将1D裂缝密度（P10）转换为体积约束（P32），从而实现3D DFN构建。基于oda的升级显示了渗透率的各向异性，其最大值分别为0.268 mD （x方向）、0.277 mD （y方向）和0.135 mD （z方向），受低倾角NE/NW裂缝的控制，同时在裂缝富集区杨氏模量、泊松比和局部应力扰动也有所降低。模拟的地应力与现场测量结果一致，验证了模型。该工作流程弥补了多尺度数据差距，为优化低渗透HDR系统的水力压裂提供了关键见解。

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引用次数: 0

An updated model of Ohaaki geothermal field, New Zealand 新西兰奥哈基地热田的更新模型

IF 3.5 2区工程技术 Q3 ENERGY & FUELS

Geothermics

Pub Date : 2025-04-14 DOI: 10.1016/j.geothermics.2025.103339

John O'Sullivan , Michael Gravatt , Jeremy Riffault , Theo Renaud , Michael O'Sullivan , Nataly Castillo Ruiz , Bridget Ayling , Warren Mannington

The University of Auckland has been collaborating with Contact Energy Limited (and its predecessors) for many years on computer modelling of the Ohaaki Geothermal Field. This paper describes the latest model that has been developed over the last 4 years. It is based on an updated digital conceptual model that is used, with our modelling framework, to set up a reservoir model that can be run in either AUTOUGH2 (our version of the well-known simulator TOUGH2) or in Waiwera, our own highly parallelized simulator.

The new digital conceptual model gives an improved representation of the geological formations, the faults and the alteration zone and the corresponding numerical model gives an improved match to most of the data. The new model produces much better results for temperature decline and pressure decline followed by pressure recovery in the deep wells, such as BR59, BR60 and BR61, on the West Bank of the Waikato River.

奥克兰大学多年来一直与Contact Energy Limited（及其前身）合作开发Ohaaki地热田的计算机模型。本文描述了过去4年来开发的最新模型。它基于一个更新的数字概念模型，该模型与我们的建模框架一起用于建立油藏模型，该模型可以在AUTOUGH2（我们著名的模拟器TOUGH2的版本）或Waiwera（我们自己的高度并行模拟器）中运行。新的数字概念模型改进了地质构造、断层和蚀变带的表示，相应的数值模型对大部分数据的拟合得到了改进。在怀卡托河西岸的BR59、BR60和BR61等深井中，新模型对温度下降和压力下降后的压力恢复有更好的结果。

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