Advances in Water Resources最新文献_第10页

Anisotropy of two-phase relative permeability in porous media and its implications for underground hydrogen storage 多孔介质中两相相对渗透率的各向异性及其对地下储氢的影响

IF 4.2 2区环境科学与生态学 Q1 WATER RESOURCES

Advances in Water Resources

Pub Date : 2025-09-20 DOI: 10.1016/j.advwatres.2025.105127

Ruichang Guo, Hongsheng Wang, Reza Ershadnia, Seyyed A. Hosseini

Subsurface rocks with anisotropic pore structures that exhibit anisotropic absolute permeability also tend to display anisotropic behavior in relative permeability. As a key input for reservoir simulation, relative permeability is essential for evaluating and optimizing the performance of subsurface energy systems. However, this anisotropy is often overlooked in simulations due to the complexity involved in its characterization under varying conditions. A major challenge lies in the fact that relative permeability anisotropy is influenced by multiple factors, including fluid saturation, rock wettability, and the capillary number of the displacement process. Unlike absolute permeability, which can be succinctly characterized using an anisotropy ratio, relative permeability lacks a similarly concise representation. This study investigated how these factors affect relative permeability anisotropy in the context of underground hydrogen storage and provides insights for its modeling. Three types of porous media were designed to represent key forms of anisotropic pore structures: stratified sedimentary structure (SSS), directionally varying pore geometry (DVPG), and oriented fracture network (OFN). Direct pore-scale simulations using the lattice Boltzmann method were conducted to examine the anisotropic behavior of relative permeability in each medium. The degree of anisotropy was quantified using a relative permeability anisotropy ratio,

R_{r A}

, and its dependence on water saturation and wettability was analyzed. Results showed that

R_{r A}

in the SSS medium varied significantly with water saturation and wettability, while

R_{r A}

in DVPG and OFN media remained largely insensitive to these factors. A geometric average anisotropy ratio,

{\bar{R}}_{r A}

, was proposed to characterize the overall degree of relative permeability anisotropy under specific wetting conditions. This metric showed that

{\bar{R}}_{r A}

, was greater than 1 for all porous media types and was comparable in magnitude to the absolute permeability ratio. These findings suggested that neglecting relative permeability anisotropy in reservoir simulations could introduce significant errors. The results enhanced theoretical understanding of two-phase flow in complex porous media and offered practical guidance for reservoir-scale modeling in anisotropic formations.

具有各向异性孔隙结构的地下岩石，其绝对渗透率表现出各向异性，相对渗透率也表现出各向异性。相对渗透率作为储层模拟的关键输入，对于评价和优化地下能量系统的性能至关重要。然而，由于在不同条件下表征的复杂性，这种各向异性在模拟中经常被忽视。一个主要的挑战在于相对渗透率的各向异性受到多种因素的影响，包括流体饱和度、岩石润湿性和驱替过程的毛管数。绝对渗透率可以用各向异性比率来简洁地表征，而相对渗透率则缺乏类似的简洁表示。本研究探讨了这些因素如何影响地下储氢条件下的相对渗透率各向异性，并为其建模提供了见解。三种多孔介质被设计为代表各向异性孔隙结构的关键形式：层状沉积结构（SSS）、定向变化孔隙几何形状（DVPG）和定向裂缝网络（OFN）。采用晶格玻尔兹曼方法进行了直接孔隙尺度模拟，以检验每种介质中相对渗透率的各向异性行为。利用相对渗透率各向异性比（RrA）量化了各向异性程度，并分析了各向异性对含水饱和度和润湿性的依赖关系。结果表明，SSS介质的RrA随含水饱和度和润湿性变化显著，而DVPG和OFN介质的RrA对这些因素基本不敏感。提出了几何平均各向异性比R¯rA来表征特定润湿条件下相对渗透率各向异性的总体程度。该指标表明，对于所有多孔介质类型，R¯rA都大于1，其量级与绝对渗透率比相当。这些发现表明，在油藏模拟中忽略相对渗透率的各向异性可能会引入显著的误差。研究结果增强了对复杂多孔介质中两相流动的理论认识，为各向异性地层的储层尺度建模提供了实践指导。

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引用次数: 0

Influence of froude number on the development and evolution of secondary flows in a sharply curved bend: An experimental and numerical study 弗劳德数对陡直弯道内二次流发展演变的影响：实验与数值研究

IF 4.2 2区环境科学与生态学 Q1 WATER RESOURCES

Advances in Water Resources

Pub Date : 2025-09-20 DOI: 10.1016/j.advwatres.2025.105126

Chengwei Hu , Yujiao Liu , Minghui Yu

Meandering rivers sculpt landscapes and foster diverse ecosystems, with secondary flows in bends exerting a pivotal influence on sediment transport and channel morphology. Although the Froude number typically remains below 0.3 in natural meanders, the interplay of secondary flows under these low-Froude conditions is still poorly understood. This study addresses this knowledge gap by systematically examining the influence of Froude numbers (Fr = 0.12-0.21) on secondary flow structures in sharply curved channels through high-resolution flume experiments and numerical simulations. Results reveal that even slight variations in Froude number can markedly alter vortex dynamics and secondary flow complexity, underscoring a delicate balance between inertial and turbulent forces. In particular, the stability of S2-type secondary flows depends on the precise alignment of advective, centrifugal, and turbulence-induced vorticity. Minor shifts in inertial forcing can rapidly destabilize S2, leading to significant changes in velocity distributions. Additionally, a time or spatial lag between the onset of secondary circulation and the point of maximum velocity inversion points to a dynamic, two-way feedback between the secondary flow and the main flow, evolving from robust vortex growth at lower Fr to flow decay at higher Fr. These findings advance our understanding of secondary flow mechanisms in natural rivers and offer practical insights for river engineering and flood management, informing more effective strategies for sediment control and bank stability.

曲流塑造了景观，培育了多样的生态系统，弯道处的二次流对泥沙运移和河道形态产生了关键影响。虽然在自然曲流中弗劳德数通常保持在0.3以下，但在这些低弗劳德条件下二次流的相互作用仍然知之甚少。本研究通过高分辨率水槽实验和数值模拟，系统地考察了弗劳德数（Fr = 0.12-0.21）对急剧弯曲通道中二次流结构的影响，从而解决了这一知识缺口。结果表明，即使弗劳德数的微小变化也能显著改变涡动力学和二次流的复杂性，强调惯性和湍流力之间的微妙平衡。特别是，s2型二次流的稳定性取决于平流、离心和湍流诱导涡度的精确对齐。惯性力的微小变化可以迅速破坏S2的稳定，导致速度分布的显著变化。此外，从二次环流开始到最大速度反转点之间的时间或空间滞后表明，二次流和主流之间存在动态的双向反馈，从较低Fr时的强劲涡增长演变为较高Fr时的流量衰减。这些发现促进了我们对天然河流二次流机制的理解，并为河流工程和洪水管理提供了实用的见解。为泥沙控制和河岸稳定提供更有效的策略。

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引用次数: 0

Modeling hydro-thermal processes in fractured geothermal reservoirs using embedded discrete fracture model (EDFM) and MRST 基于嵌入离散裂缝模型（EDFM）和MRST的裂缝性地热储层热液过程建模

IF 4.2 2区环境科学与生态学 Q1 WATER RESOURCES

Advances in Water Resources

Pub Date : 2025-09-17 DOI: 10.1016/j.advwatres.2025.105120

Tongchao Nan , Tianwei Hu , Zichen Wang , Jiangjiang Zhang , Jina Yin , Yifan Xie , Jichun Wu , Chunhui Lu

Fractures critically influence fluid flow and heat transfer in geothermal reservoirs, necessitating accurate and efficient simulation tools for resource management. Here we introduce ETH, an open-source Embedded Discrete Fracture Model (EDFM) module integrated with the MATLAB Reservoir Simulation Toolbox (MRST), enabling coupled hydrothermal simulations in both 2D and 3D fractured porous media. ETH extends prior EDFM frameworks by incorporating heat transfer and variable fluid properties, validated through four benchmarks ranging from analytical single-fracture cases to complex 3D fracture networks. Results demonstrate high accuracy (relative errors mostly <1 %) and computational efficiency, with 20–50 % reduced cost compared to FEM-based discrete fracture models. ETH’s modular design supports mesh/time convergence control and integration of additional physics, facilitating robust modeling of heterogeneous and anisotropic reservoirs. This tool advances accessible, high-fidelity simulation capabilities for geothermal reservoir characterization, development, and uncertainty quantification.

裂缝对地热储层的流体流动和换热具有重要影响，因此需要精确、高效的模拟工具来进行资源管理。在这里，我们介绍ETH，一个开源的嵌入式离散裂缝模型（EDFM）模块，集成了MATLAB油藏模拟工具箱（MRST），可以在二维和三维裂缝性多孔介质中耦合热液模拟。ETH扩展了之前的EDFM框架，结合了传热和可变流体特性，并通过从分析单裂缝案例到复杂3D裂缝网络的四个基准进行了验证。结果表明，与基于有限元的离散裂缝模型相比，该模型具有较高的精度（相对误差约为1%）和计算效率，成本降低了20 - 50%。ETH的模块化设计支持网格/时间收敛控制和额外物理的集成，促进了非均质和各向异性油藏的稳健建模。该工具为地热储层表征、开发和不确定性量化提供了方便、高保真的模拟能力。

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引用次数: 0

Modeling tracer dispersion in a coupled system composed of a proppant-packed hydraulic fracture and a tight porous medium 模拟含支撑剂的水力裂缝和致密多孔介质耦合系统中的示踪剂分散

IF 4.2 2区环境科学与生态学 Q1 WATER RESOURCES

Advances in Water Resources

Pub Date : 2025-09-16 DOI: 10.1016/j.advwatres.2025.105122

Morteza Dejam

Tracer tests are widely performed for the characterization of reservoir properties during the hydraulic fracturing operation. The dispersion of the tracer depends on the interaction of the proppant-packed hydraulic fracture and the tight porous medium through the naturally porous walls. However, the effects of the interaction of the porous walls and dynamics of flow in the proppant-packed hydraulic fracture on the tracer dispersion and reservoir dynamic mass/heat storage capacity have not yet been reported in the literature. In this work, the tracer dispersion in a proppant-packed hydraulic fracture surrounded by a tight porous medium is theoretically modeled and the dynamic storage capacity is evaluated. The Darcy-Brinkman equation is used to describe the fully developed laminar Stokes fluid flow in the proppant-packed hydraulic fracture. We used the Taylor dispersion theory and Reynolds decomposition approach to derive the exact equivalent transport parameters, including dispersion and advection coefficients, as well as the storage capacity of the tight porous medium. It is found that the tracer dispersion is controlled by the Darcy and the Peclet numbers in the proppant-packed hydraulic fracture. The results indicate that the ratio of tracer dispersion in the proppant-packed hydraulic fracture with porous walls to that with nonporous walls ranges from zero for very small Darcy numbers to 0.3 for large Darcy numbers. The ratio of the advection velocity in the proppant-packed hydraulic fracture with porous walls to that with nonporous walls ranges from unity for very small Darcy numbers to 7/5 for large Darcy numbers. The results also indicate that tracer mass storage capacity in the tight porous medium increases as the Peclet number for fluid flow in the proppant-packed hydraulic fracture increases. Conversely, storage decreases as the Darcy number in the proppant-packed hydraulic fracture rises. A comparison reveals that a flow transport model based on proppant-free hydraulic fracture may lead to the overestimation of the tracer mass/heat storage capacity. The findings of this study pave the way to advance our understanding of tracer tests for evaluating reservoir characteristics during fracturing operations in enhanced geothermal systems.

在水力压裂作业中，示踪剂测试被广泛用于表征储层性质。示踪剂的分散取决于支撑剂充填的水力裂缝与穿过天然多孔壁的致密多孔介质的相互作用。然而，在支撑剂充填的水力裂缝中，多孔壁的相互作用和流动动力学对示踪剂分散性和储层动态质量/储热能力的影响尚未在文献中报道。在这项工作中，理论模拟了被致密多孔介质包围的支撑剂填充水力裂缝中的示踪剂分散，并评估了动态存储容量。Darcy-Brinkman方程用于描述支撑剂充填水力裂缝中完全发育的层流Stokes流体流动。我们使用Taylor色散理论和Reynolds分解方法推导出精确的等效输运参数，包括色散和平流系数，以及致密多孔介质的存储容量。研究发现，在充填支撑剂的水力裂缝中，示踪剂的分散受Darcy数和Peclet数的控制。结果表明，在支撑剂填充的水力裂缝中，多孔壁与非多孔壁的示踪剂弥散比在达西数很小时为0，在达西数很大时为0.3。在支撑剂填充的水力裂缝中，多孔壁面的平流速度与无孔壁面的平流速度之比从很小的达西数为1到很大的达西数为7/5不等。结果还表明，随着支撑剂充填水力裂缝中流体流动的Peclet数的增加，致密多孔介质中示踪剂的质量存储容量也随之增加。相反，随着支撑剂充填水力裂缝中达西数的增加，储层会减少。对比表明，基于无支撑剂水力压裂的流动输运模型可能会导致对示踪剂质量/储热能力的高估。这项研究的发现为我们进一步了解在增强型地热系统压裂作业中，用于评估储层特征的示踪测试铺平了道路。

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引用次数: 0

Monitoring drywell infiltration dynamics using time-lapse electrical resistivity tomography 利用延时电阻率层析成像技术监测干井渗透动态

IF 4.2 2区环境科学与生态学 Q1 WATER RESOURCES

Advances in Water Resources

Pub Date : 2025-09-13 DOI: 10.1016/j.advwatres.2025.105102

Z. Moreno , L. Netzer , U. Nachshon , D. Kurtzman , Y. Livshitz , T. Kamai

Drywell infiltration initiates as water is injected into the drywell. Subsequently, the water level in the drywell builds up the driving head of water flow into the subsurface via the surface area of the drywell. Drywell infiltration is a function of the surrounding media’s hydraulic properties, the drywell’s geometry, and the injection rate. The drywell infiltration capacity property determines the water volume that can infiltrate the subsurface for different injection rates without overspilling. This property can be evaluated under controlled infiltration experiments where water levels in the drywell are continuously monitored during injection. However, no available method exists for revealing spatiotemporal information on the subsurface flow mechanisms, including flow patterns and residual time at the vadose zone. Conventional methods for monitoring the subsurface are intrusive, expensive, and can provide limited information, especially on the spatial extent. Unlike conventional monitoring techniques, electrical resistivity tomography (ERT) can provide continuous, non-invasive information on the subsurface in an easy-to-apply and efficient manner. We examine the ERT applicability to monitor water dynamics at the deep vadose zone (at depths of 20–40 m), induced by drywell infiltration. For that purpose, electrodes were installed at the surface, in the perforated section of the drywell, and at a wetwell, located 5 m from the dry one. Time-lapse ERT surveys were conducted during a controlled drywell infiltration experiment, including the borehole and surface electrodes. The results show that the relative changes in the electrical conductivity can describe water dynamics during the infiltration experiment. Saturation maps translated from the electrical tomograms using calibrated petrophysical relations preserved the water mass balance injected into the well up to

\sim

250 min after the injection started. Modeling this experiment with a semi-analytical solution, assuming a sharp-wetting front interface, agreed with the wetting front location from the time-lapse electrical tomograms and with the water levels measured in the drywell.

干井渗透开始于水注入干井。随后，干井中的水位通过干井的表面形成水流进入地下的驱动头。干井渗透是周围介质水力特性、干井几何形状和注入速度的函数。干井渗透能力特性决定了在不同注入速率下能渗入地下而不溢水的水量。这种特性可以通过控制渗透实验来评估，在注入过程中连续监测干井中的水位。然而，目前还没有有效的方法来揭示地下流动机制的时空信息，包括渗流带的流动模式和剩余时间。传统的地下监测方法是侵入性的，昂贵的，而且只能提供有限的信息，特别是在空间范围上。与传统的监测技术不同，电阻率层析成像（ERT）可以以一种易于应用和有效的方式提供连续的、非侵入性的地下信息。我们检验了ERT对监测干井入渗引起的深层渗透带（深度20-40 m）水动力学的适用性。为此，电极被安装在干井表面、干井穿孔段和湿井处，距干井5米。在受控干井渗透实验期间进行了延时ERT测量，包括井眼和地面电极。结果表明，电导率的相对变化可以描述入渗试验过程中的水动力学。利用校准过的岩石物理关系，从电层析图转换而来的饱和度图在注入开始后的~ 250分钟内保持了注入井中的水质量平衡。采用半解析解对实验进行建模，假设有一个尖锐润湿前沿界面，与从延时电断层图中得到的润湿前沿位置和干井中测量的水位一致。

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引用次数: 0

Hydrothermal evolution of high-latitude frozen soil during freeze-thaw cycles 高纬度冻土在冻融循环中的热液演化

IF 4.2 2区环境科学与生态学 Q1 WATER RESOURCES

Advances in Water Resources

Pub Date : 2025-09-13 DOI: 10.1016/j.advwatres.2025.105121

Jiao Huang , Xiabing Yue , Xueying Wang , Hongwei Zhang

The primary factors causing road damage in high-latitude areas are frost heave and thaw settlement, which are governed by hydrothermal changes. An indoor freeze-thaw cycle test based on similarity theory was conducted to analyze the hydrothermal evolution of high-latitude frozen soil in Northeast China. The results were verified by field data. A hydro-thermal coupling Eq. was established by using finite element software. The experimental and simulation results were compared to validate the finite element model of the soil column. The freeze-thaw cycles exhibited three distinct phases: freezing initiation, peak freezing intensity, and thawing. The soil moisture at the end of each freeze-thaw cycle increased, decreased, and increased. The proposed hydrothermal coupling model was used to describe the long-term freeze-thaw behavior of typical subgrade sections in high-latitude permafrost regions of China. The model based on similar particle gradation proved accurate.

高纬度地区道路破坏的主要原因是冻胀和融化沉降，而冻胀和融化沉降受热液变化的支配。基于相似理论的室内冻融循环试验，分析了东北高纬度冻土热液演化过程。实测数据验证了结果的正确性。利用有限元软件建立了水热耦合方程。将试验结果与仿真结果进行对比，验证了土柱有限元模型的正确性。冻融循环表现为冻结起始阶段、冻结峰值阶段和解冻阶段。在每个冻融循环结束时，土壤水分依次增加、减少和增加。利用所建立的水热耦合模型对中国高纬多年冻土区典型路基段的长期冻融行为进行了描述。基于相似颗粒级配的模型被证明是准确的。

引用次数: 0

Advanced numerical investigation of flow field and morphological evolution around tandem piers 串联桥墩周围流场及形态演化的先进数值研究

IF 4.2 2区环境科学与生态学 Q1 WATER RESOURCES

Advances in Water Resources

Pub Date : 2025-09-13 DOI: 10.1016/j.advwatres.2025.105119

Suniti Kumari, H.L. Tiwari, Rutuja Chavan

Bridge pier scour around tandem piers constitutes a complex hydrodynamic phenomenon necessitating sophisticated numerical modeling for accurate prediction and mitigation strategies. This study employed FLOW-3D Hydro with LES turbulence model and Q-criterion vortex identification methodology to elucidate vortex-induced scour mechanisms at the vicinity of tandem arrangements, T1 and T2 under varying flow conditions. Numerical model validation achieved accuracies of 1.30–5.30 % against experimental observations, revealing best agreement with scour depths across all analysed arrangements. Morphological analysis reveals substantial configurational dependencies, with T2 arrangement exhibiting maximum scour depth as compared to T1. Interference of WVs significantly reduced scour by 38 % (T1) and 56 % (T2) at rear piers, elucidating the critical influence of pier diameter sequencing on erosional patterns. Findings established correlation between scour patterns and hydrodynamic parameters including velocity profiles, RSS and Q-criterion vortex structures, which are fundamental in understanding scour development. The velocity profiles and RSS distributions were analysed at three key section to assess flow characteristics and vortex behaviour around tandem piers. The Q-criterion methodology identifies coherent vortex structure as regions where rotational motion dominates strain, providing detailed visualisation and quantification of vortical structures responsible for scour development. Q-criterion analysis adequately identified coherent vortex structures with varying intensities at both u/s and d/s pier locations. In the complex flow region between the front and rear pier, Q-criterion vortex structures effectively captured the sheltering phenomenon where WVs from the u/s pier disrupted coherent vortex formation at the d/s pier. These vortical interactions resulted in substantial scour depth reductions of 38 % and 56 % for T1 and T2 arrangements, respectively. This paper contributes to a fundamental understanding of vortex-induced scour dynamics around complex pier arrangement, which is critical for designing resilient bridge foundations.

串联墩周围的桥墩冲刷是一种复杂的水动力现象，需要复杂的数值模拟来进行准确的预测和缓解策略。本研究采用flow - 3d Hydro结合LES湍流模型和q准则涡识别方法，阐明了不同流动条件下串联布置、T1和T2附近涡激冲刷机理。数值模型验证达到了1.30 - 5.30%的实验观测精度，揭示了在所有分析安排冲刷深度的最佳协议。形态分析揭示了大量的构型依赖性，与T1相比，T2排列显示出最大的冲刷深度。WVs的干扰显著降低了后桥墩38% （T1）和56% （T2）的冲刷，阐明了桥墩直径排序对侵蚀模式的关键影响。研究结果建立了冲刷模式与水动力参数（包括速度剖面、RSS和q准则涡结构）之间的相关性，这是理解冲刷发展的基础。分析了三个关键断面的速度分布和相对旋转速率分布，以评估串联桥墩周围的流动特性和涡行为。q准则方法将相干涡结构识别为旋转运动主导应变的区域，提供了负责冲刷发展的涡结构的详细可视化和量化。q准则分析充分识别了u/s和d/s桥墩位置上不同强度的相干涡结构。在前后桥墩之间的复杂流动区，q准则涡结构有效地捕捉到了u/s桥墩WVs干扰d/s桥墩相干涡形成的遮挡现象。这些涡旋相互作用导致T1和T2布置的冲刷深度分别减少38%和56%。本文有助于对复杂桥墩布置涡激冲刷动力学的基本认识，这对设计弹性桥梁基础具有重要意义。

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引用次数: 0

Semi-analytical solutions for nonequilibrium transport and transformation of PFAS and other solutes in heterogeneous vadose zones with structured porous media 结构多孔介质中PFAS和其他溶质在非均质渗透带中的非平衡输运和转化的半解析解

IF 4.2 2区环境科学与生态学 Q1 WATER RESOURCES

Advances in Water Resources

Pub Date : 2025-09-12 DOI: 10.1016/j.advwatres.2025.105099

Sidian Chen , Bo Guo

We present screening-type semi-analytical models for quantifying the fate and transport of PFAS, including perfluoroalkyl acids (PFAAs) and their precursors (i.e., polyfluoroalkyl substances that can transform to PFAAs), in a heterogeneous vadose zone. The models employ one-dimensional multi-continuum representations with varying complexities (dual-porosity, dual-permeability, or triple-porosity). They account for PFAS-specific transport processes, including multi-site rate-limited adsorption at solid–water and air–water interfaces, and first-order biochemical transformation. Assuming steady-state infiltration, we derive semi-analytical solutions for all models under arbitrary initial and boundary conditions. We validate these new solutions using literature experimental breakthrough curves of PFAS and other solutes for various soils and wetting conditions. Furthermore, we demonstrate the models’ capability by analyzing the long-term leaching and mass discharge of two example PFAS (PFOS and a precursor PFOSB) in a heterogeneous vadose zone beneath a model PFAS-contaminated site. The results demonstrate that the precursor undergoes significant transformation and adds additional PFOS mass discharge to groundwater. Additionally, the simulations suggest that, due to strong retention in the vadose zone (i.e., large residence time), the PFAS in the high- and low-conductivity transport pathways can be considered as in equilibrium. Taking advantage of this result, we illustrate that the multi-continuum models may be simplified to an effective single-porosity model for simulating the transport of longer-chain PFAS in a heterogeneous vadose zone. Overall, the semi-analytical models provide practical tools for assessing long-term fate and transport of PFAS in the vadose zone and mass discharge to groundwater in the presence of precursor transformations.

我们提出了筛选型半分析模型，用于定量PFAS的命运和运输，包括全氟烷基酸（PFAAs）及其前体（即，可以转化为PFAAs的多氟烷基物质），在异质渗透区。这些模型采用一维多连续体表示，具有不同的复杂性（双孔隙度、双渗透率或三孔隙度）。它们解释了pfas特异性的运输过程，包括在固体-水和空气-水界面的多位点速率限制吸附，以及一级生化转化。假设稳态渗透，在任意初始和边界条件下，我们得到了所有模型的半解析解。我们利用PFAS和其他溶质在不同土壤和湿润条件下的实验突破曲线验证了这些新的解决方案。此外，我们通过分析两种示例PFAS （PFOS和前体PFOSB）在模型PFAS污染场地下方的非均质渗透带中的长期浸出和大量排放来证明模型的能力。结果表明，前驱体发生了明显的转化，增加了PFOS向地下水的大量排放。此外，模拟结果表明，由于PFAS在气包带中的滞留时间较长（即停留时间较长），可以认为PFAS在高电导率和低电导率的运输途径中处于平衡状态。利用这一结果，我们说明了多连续介质模型可以简化为一个有效的单孔隙模型来模拟长链PFAS在非均质渗透带中的输运。总的来说，半解析模型提供了实用的工具来评估PFAS在渗流带的长期命运和运输，以及在前体转化存在的情况下向地下水的大量排放。

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引用次数: 0

Pore-scale imaging of hydrogen and methane storage in fractured aquifer rock: The impact of gas type on relative permeability 裂缝性含水层储氢甲烷孔隙尺度成像：气型对相对渗透率的影响

IF 4.2 2区环境科学与生态学 Q1 WATER RESOURCES

Advances in Water Resources

Pub Date : 2025-09-10 DOI: 10.1016/j.advwatres.2025.105109

Sojwal Manoorkar , Gülce Kalyoncu , Hamdi Omar , Soetkin Barbaix , Dominique Ceursters , Maxime Latinis , Stefanie Van Offenwert , Tom Bultreys

Underground hydrogen storage in saline aquifers is a potential solution for seasonal renewable energy storage. Among potential storage sites, facilities used for underground natural gas storage have advantages, including well-characterized cyclical injection-withdrawal behavior and partially reusable infrastructure. However, the differences between hydrogen-brine and natural gas-brine flow, particularly through fractures in the reservoir and the sealing caprock, remain unclear due to the complexity of two-phase flow. Therefore, we investigate fracture relative permeability for hydrogen versus methane (natural gas) and nitrogen (commonly used in laboratories). Steady-state relative permeability experiments were conducted at 10 MPa on fractured carbonate rock from the Loenhout natural gas storage in Belgium, where gas flows through

μ

m-to-mm scale fractures. Our results reveal that the hydrogen exhibits similar relative permeability curves to methane, but both are significantly lower than those measured for nitrogen. This implies that nitrogen cannot reliably serve as a proxy for hydrogen at typical reservoir pressures. The low relative permeabilities for hydrogen and methane indicate strong fluid phase interference, which traditional relative permeability models fail to capture. This is supported by our observation of periodic pressure fluctuations associated with intermittent fluid connectivity for hydrogen and methane. In conclusion, our findings suggest that the fundamental flow properties of fractured rocks are complex but relatively similar for hydrogen and natural gas. This is an important insight for predictive modeling of the conversion of Loenhout and similar natural gas storage facilities, which is crucial to evaluate their hydrogen storage efficiency and integrity.

盐碱层地下储氢是季节性可再生能源储存的潜在解决方案。在潜在的储存地点中，用于地下天然气储存的设施具有优势，包括具有良好特征的周期性注入-提取行为和部分可重复使用的基础设施。然而，由于两相流的复杂性，盐水氢流和天然气盐水流之间的区别仍然不清楚，特别是通过储层和密封盖层的裂缝。因此，我们研究了氢气与甲烷（天然气）和氮气（通常用于实验室）的裂缝相对渗透率。以比利时Loenhout天然气储层碳酸盐岩裂缝为研究对象，在10 MPa条件下进行了稳态相对渗透率实验。结果表明，氢气的相对渗透率曲线与甲烷相似，但两者都明显低于氮的相对渗透率曲线。这意味着在典型的储层压力下，氮不能可靠地作为氢的代表。氢气和甲烷相对渗透率较低，表明流体相干扰较强，这是传统相对渗透率模型无法捕捉的。我们观察到与氢气和甲烷的间歇性流体连通性相关的周期性压力波动，这一点得到了支持。综上所述，我们的研究结果表明，裂缝岩石的基本流动特性是复杂的，但氢气和天然气的基本流动特性相对相似。这是对Loenhout和类似天然气储存设施转换的预测建模的重要见解，这对于评估其储氢效率和完整性至关重要。

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引用次数: 0

Estimating the full anisotropy of the covariance function in geostatistical inversion using the pilot-point ensemble Kalman filter 利用导点集合卡尔曼滤波估计地统计反演中协方差函数的全各向异性

IF 4.2 2区环境科学与生态学 Q1 WATER RESOURCES

Advances in Water Resources

Pub Date : 2025-09-09 DOI: 10.1016/j.advwatres.2025.105103

Janek Geiger, Michael Finkel, Olaf A. Cirpka

In geostatistical inversion, good prior knowledge about the covariance function is important in estimating hydraulic conductivity from hydraulic-head observations, but may be hampered by poor knowledge about anisotropy. In this study we propose an extension of the pilot-point ensemble Kalman filter (PP-EnKF) that can infer the full anisotropy of the covariance function based on attainable, initially random knowledge. We address the periodicity of rotation by incorporating the unique elements of the covariance transformation matrix into the set of parameters to be estimated. The filter is further modified by generating conditional realizations in each assimilation step, increasing the inherent variance of the ensemble and counteracting filter inbreeding. We demonstrate the methodology in a synthetic study of a 2-D groundwater-flow model where we estimate the full anisotropy of the covariance function and the hydraulic conductivity at pilot points via the assimilation of hydraulic-head data. The success of this method depends more on the configuration of pilot points than on the quality of prior knowledge, as ensembles initialized with faulty random priors successfully estimated the correct parameters of the covariance function, as well as the log-hydraulic conductivity values at the pilot points. The resulting parameter fields enabled accurate predictions of hydraulic heads during a verification period, with normalized root mean square errors reduced by up to 66% compared to ensembles with isotropic covariance functions. The methodology presented in this study mitigates the importance of informative prior knowledge of the covariance function in geostatistical parameter-inference methods, especially in highly anisotropic settings.

在地质统计反演中，关于协方差函数的良好先验知识对于从水头观测中估计水力导电性很重要，但可能会受到各向异性知识不足的阻碍。在这项研究中，我们提出了一个扩展的导点集合卡尔曼滤波器（PP-EnKF），可以推断协方差函数的全各向异性基于可获得的，最初的随机知识。我们通过将协方差变换矩阵的唯一元素纳入待估计的参数集来处理旋转的周期性。通过在每个同化步骤中生成条件实现来进一步改进滤波器，增加集合的固有方差并抵消滤波器的近亲繁殖。我们在一个二维地下水流动模型的综合研究中演示了该方法，通过同化水头数据，我们估计了协方差函数的全各向异性和导点的水力导电性。该方法的成功更多地取决于导频点的配置，而不是先验知识的质量，因为用错误随机先验初始化的集合成功地估计了协方差函数的正确参数，以及导频点的对数-水力导频值。由此产生的参数字段能够在验证期间准确预测水力水头，与具有各向同性协方差函数的集成相比，标准化均方根误差减少了66%。本研究提出的方法减轻了协方差函数的信息先验知识在地质统计参数推断方法中的重要性，特别是在高度各向异性的环境中。

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