Geomechanics for Energy and the Environment最新文献_第4页

Integrating geomechanical proxy models with data assimilation for energy transition applications

IF 3.3 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2024-12-01 DOI: 10.1016/j.gete.2024.100618

Ilshat Saifullin , Gabriel Serrão Seabra , Anne Pluymakers , Femke C. Vossepoel , Denis Voskov

This study presents a method to address the significant uncertainties in subsurface modeling that impact the efficiency of energy transition applications such as geothermal energy extraction and CO

_{2}

geological sequetsration. The approach combines a physics-based geomechanical proxy model with an ensemble smoother with multiple data assimilation (ES-MDA), aimed at enhancing uncertainty quantification through the integration of vertical displacement measurements from fluid production and injection. The data from wells is limited in spatial coverage, while these measurements offer extensive spatial information, improving the understanding of subsurface behavior by reflecting changes in reservoir pressure and temperature. The open-DARTS simulator for fluid flow and a geomechanical proxy are used to perform data assimilation with ES-MDA. By generating an ensemble of model realizations with varied permeability, calculating vertical displacements at the surface, and applying ES-MDA, we effectively identify the probability distribution of the vertical displacement of the model conditioned to observed subsidence data. Entropy is used as a statistical measure to quantify the reduction of uncertainty of subsurface models based on observations. Our approach was tested on a 2D conceptual and 3D realistic datasets, demonstrating its capability to provide data assimilation. This workflow represents an advancement in subsurface modeling, supporting informed decision-making in geothermal energy production and CO

_{2}

sequestration by offering an improved alternative for data assimilation and enhancing tools for uncertainty quantification.

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引用次数: 0

Soft interface instability and gas flow channeling in low-permeability deformable media

IF 3.3 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2024-12-01 DOI: 10.1016/j.gete.2024.100622

Yifeng Wang , Teklu Hadgu , Boris Faybishenko , Jon Harrington , Elena Tamayo-Mas , Kristopher L. Kuhlman , Carlos F. Jove-Colon

Understanding gas percolation through a clay layer or a shale formation is of great importance for the development of a geologic repository for nuclear waste disposal, a subsurface system for gas storage, and an engineering approach for hydrocarbon extraction from unconventional reservoirs. Gas injection experiments have revealed complex dynamic behaviours of gas percolation through water saturated compacted bentonite, characterized by a high breakthrough pressure, rapid breakthrough, a pressure/stress decay after the breakthrough, a relatively high migration rate, high-frequency periodic/nonperiodic variations in flow rate, stepwise rate reductions during relaxation, and low gas saturation over the whole process, all indicating channelling nature of the processes. Using linear stability analyses, we show that this channelling can autonomously emerge from the instability of the deformable interface between the injected gas and the compacted bentonite matrix driven by local stress concentration, pore dilation, and hydrologic gradient. Channel patterns formed would possess a fractal geometry. We further show that, once a percolating channel is established, the gas injected would percolate through the channel in a chain of gas bubbles, also due to the interface instability, resulting in periodic/chaotic variations in gas flow rate. Our work provides a unified explanation for key features observed for gas percolation in low-permeability deformable media. The work also suggests a possibility of designing an engineered barrier system for a nuclear waste repository that can have controllable gas release while limit water transport.

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引用次数: 0

Coupled hydro-gas-mechanical 3D modeling of LASGIT experiment

IF 3.3 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2024-12-01 DOI: 10.1016/j.gete.2024.100623

B.S. Noghretab , I.P. Damians , S. Olivella , A. Gens

Gas transport simulation in bentonite for radioactive waste disposal poses challenges for numerical models due to its complex microstructure. Understanding the processes involved is a prerequisite for assessing gas flow's impact on repository layouts. The DECOVALEX23 (D-2023) Task B (Large Scale Gas Injection Test: LASGIT) project aims to advance numerical techniques for predicting gas flow in repository systems through gas injection tests on compacted bentonite at the British Geological Survey (BGS). This study develops a comprehensive coupled hydro-gas-mechanical 3D numerical model to simulate the test, considering heterogeneous initial permeability and embedded fractures. Addressing bentonite swelling, three gap closure scenarios for the canister-bentonite blocks gap interface were considered. The model reproduces observed test behaviors, capturing preferential gas flow paths. Sensitivity analysis explores variations in volume factor sensitivity, calibration, hydraulic conductivity of interfaces, heterogeneity, permeability, and model parameters, contributing to a deeper understanding of the phenomenon's complexity. The proposed hydraulic modeling, enriched by considerations of gap closure states, predicts measured evolution of gas injection trends. suggesting reliability and potential applicability for similar conditions and facilitating a comprehensive analysis of its impact on gas testing processes. Additionally, the embedded fracture models underscore the critical role of fracture behavior and dilatancy in determining the system's hydro-mechanical response, with significant sensitivity to these factors influencing stress and pore pressure evolution. Hydro-mechanical models demonstrate that modeling approaches involving embedded fractures and dilatancy significantly influence gas pathways and entry gas pressure. System volume plays pivotal role in the analysis, while sensitivity analysis of contact transmissivity reveals potential influences on preferential gas pathway formation. Hydraulic and hydro-mechanical modeling methods show promise for further numerical investigations, indicating potential for yielding meaningful insights in future studies.

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引用次数: 0

Hybrid framework for surrogate modelling of massive solar collectors in road pavements 道路路面大规模太阳能集热器替代模型的混合框架

IF 3.3 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2024-12-01 DOI: 10.1016/j.gete.2024.100617

Taher Ghalandari , David M.G. Taborda , Alalea Kia , Cedric Vuye

This paper investigates the application of surrogate modelling in the design and thermal response assessment of Pavement Solar Collectors (PSCs). The PSC system is a sustainable infrastructure solution that utilises both solar and shallow geothermal energy. PSCs incorporate a network of pipes embedded in the asphalt layer to create a heat exchange layer. During warm months, water circulating through this layer captures solar heat, which can then be used for snow melting in winter, enhancing road safety, or for domestic and industrial heating applications. Finite Element (FE) analysis is a widely used method for evaluating the thermal response of PSCs to optimize their design. However, the substantial computational requirements of numerical modelling, especially for long-term time-dependent analyses, pose significant challenges in assessing the long-term thermal behaviour of PSCs. Surrogate models, approximating complex physics-based simulations, drastically reduce computational demands, enabling rapid and accurate evaluations of various design parameters and scenarios. In this study, a validated FE simulation framework was employed to generate data, which was then used to develop a data-driven surrogate model for PSCs. In order to refine the surrogate model's performance to its optimal level, hyperparameter optimisation was carried out. The comparison of outlet water temperature results between finite element and surrogate models showed a high correlation, with a coefficient of determination of 0.97 observed for both training and test data sets. Subsequently, the surrogate model was integrated as an objective function in a Particle Swarm Optimization (PSO) algorithm to automate the Heat Harvesting Capacity (HHC) optimisation of PSCs. The PSO algorithm demonstrates robust performance in identifying optimal solutions while also offering a substantial reduction in computational costs compared to FE simulations.

研究了替代模型在路面太阳能集热器（PSCs）设计和热响应评估中的应用。PSC系统是一个可持续的基础设施解决方案，利用太阳能和浅层地热能源。psc在沥青层中嵌入了一个管道网络，以形成一个热交换层。在温暖的月份，通过这一层循环的水捕获太阳热量，然后可用于冬季融雪，加强道路安全，或用于家庭和工业供暖。有限元分析是一种广泛使用的热响应评估方法，用于优化设计。然而，数值模拟的大量计算需求，特别是长期时间依赖分析，对评估psc的长期热行为提出了重大挑战。替代模型，近似复杂的基于物理的模拟，大大减少了计算需求，能够快速准确地评估各种设计参数和场景。在本研究中，采用一个经过验证的有限元模拟框架来生成数据，然后将其用于开发数据驱动的psc代理模型。为了使代理模型的性能达到最优水平，进行了超参数优化。有限元模型与代理模型的出水温度结果比较显示出较高的相关性，训练数据集与测试数据集的决定系数均为0.97。随后，将代理模型作为目标函数集成到粒子群优化（PSO）算法中，实现PSCs集热能力（HHC）的自动优化。与FE模拟相比，PSO算法在识别最优解方面表现出强大的性能，同时也大大降低了计算成本。

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引用次数: 0

Comparing modelling approaches for a generic nuclear waste repository in salt

IF 3.3 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2024-12-01 DOI: 10.1016/j.gete.2024.100621

Tara LaForce , Jeroen Bartol , Dirk-Alexander Becker , Steven Benbow , Alexander Bond , Carl Rudolf Dietl , Tanja Frank , Ingo Kock , Fabiano Magri , Josh Nicholas , Rick Jayne , Marek Pekala , Philip H. Stauffer , Emily Stein , Jodie Stone , Jens Wolf

This paper contains a comparison of five modelling approaches for a simplified nuclear waste repository in a domal salt formation. It is the result of a four-year collaboration between five international teams on Task F of the DECOVALEX-2023 project on performance assessment modelling. The primary objectives of Task F are to build confidence in the models, methods, and software used for performance assessment (PA) of deep geologic nuclear waste repositories, and/or to bring to the fore additional research and development needed to improve PA methodologies. This work demonstrates how these objectives are accomplished through staged development and comparison of the models and methods used by participating teams in their PA frameworks. Participating teams made a wide range of model assumptions, ranging from compartmentalized networks to full 3D models of the salt formation and repository. Despite differences in the modelling strategies, all models indicate that salt compaction and diffusion of radionuclides in brine are key processes in the repository. For the isothermal spent nuclear fuel and vitrified waste scenario with multiple early failures considered, all models indicate little of the disposed radionuclides will migrate beyond the repository seal over the 100,000-year simulations. In general, the model output quantities have the largest differences over the short term and near the waste. Disparities between the models are believed to be due to differing simplifications from the conceptual model.

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引用次数: 0

Functional analysis of the constitutive role of temperature in compacted bentonites 温度对压实膨润土本构作用的功能分析

IF 3.3 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2024-12-01 DOI: 10.1016/j.gete.2024.100620

Vicente Navarro , Gema Urraca , Laura Asensio

A thermodynamically consistent expression is derived for the functional structure of effective stress understood as the work conjugate of elastic strain. The study, focussed on compacted clays, is valid for both non-isothermal conditions and constant temperature. As a result, it is found that there is no evidence to assume a direct dependence of the effective stress on temperature. Therefore, it is consistent to follow the usually employed strategies based on evaluating the implicit dependence through air pressure, macrostructural liquid pressure and macrostructural degree of saturation.

导出了有效应力功能结构的热力学一致表达式，即弹性应变的功共轭。该研究的重点是压实粘土，在非等温条件和恒温条件下都是有效的。因此，没有证据表明有效应力与温度有直接关系。因此，采用通常采用的通过空气压力、宏观结构液体压力和宏观结构饱和度来评估隐含依赖性的策略是一致的。

引用次数: 0

In situ static elastic properties assessment and validation with pressuremeter testing using a formation tester tool

IF 3.3 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2024-12-01 DOI: 10.1016/j.gete.2024.100619

Jean E. Elkhoury , Thomas Bérard , Jean Desroches , Emilie Peyret , Romain Prioul , Eleonora Crisci , Rodney Garrard , Silvio B. Giger

Pressuremeter testing (PMT) is a formation test that consists of inflating a cylindrical packer inside a borehole while measuring the radial deformation or injected fluid volume as a function of packer pressure. Provided that the stiffness of the packer measuring system is known and large enough compared to that of the formation, changes in packer pressure associated with changes in injected fluid volume provide a direct measurement of formation stiffness. In turn, the in situ static shear modulus is obtained from the formation stiffness at a length scale similar to that of the packer. Here, we report on the first field-scale campaign of PMTs in deep boreholes performed using a wireline formation tester (WFT) tool. We carried out PMT measurements as part of the characterization and appraisal of potential sites for a deep geological repository for radioactive waste in Switzerland. We performed multiple PMT inflation cycles to infer in situ static shear moduli at six stations spread across four boreholes. PMT-derived static shear moduli results were consistent with static shear moduli derived from sonic logs using independent dynamic-to-static elastic moduli transformations. PMT-derived static shear moduli and laboratory-derived static elastic moduli using samples from coring performed at the depths of the PMT stations were consistent, with slightly lower laboratory values. Furthermore, we report dynamic-to-static shear moduli transformations by using laboratory-scale data obtained on cores and field-scale derived from sonic logs and PMT. We observed differences between static and dynamic shear moduli derived from laboratory scale using cores and field scale using sonic logs and PMT. We report linear trend slopes of about 0.5 for the laboratory data and 0.7 for the field data. These first results show the viability of in situ PMT in deep boreholes with a WFT tool, as it can be performed at multiple depths in a single run, in a time-efficient manner, and in combination with micro-hydraulic and sleeve fracturing stress tests for an integral approach to in situ geomechanical assessment.

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引用次数: 0

Influence of mechanical strength on gas migration through bentonite: Numerical analysis from laboratory to field scale

IF 3.3 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2024-12-01 DOI: 10.1016/j.gete.2024.100614

Jung-Tae Kim , Changsoo Lee , Minhyeong Lee , Jin-Seop Kim , E. Tamayo-Mas , J.F. Harrington

Understanding the gas movement phenomenon within the deep geological repository is essential for assessing the disposal system’s long-term stability. The primary gas transport mechanism through the bentonite is dilatancy-controlled flow, which differs from gas flow in general porous media. This flow is characterized by gas movement through microcracks created under relatively high gas pressure conditions, and the intrinsic permeability, air-entry pressure, and mechanical strength of the medium change due to the generation and propagation of these microcracks. Therefore, dilatancy-controlled flow cannot be simulated using the classical two-phase flow modeling technique. This study constructed the H

^{2}

MD (two-phase hydraulic-mechanical-damage) numerical model by combining a damage model to simulate material degradation and the resulting change in intrinsic permeability with a classical two-phase flow model. In addition, the numerical model was tested against a 1D laboratory gas injection test investing gas flow mechanisms in the buffer, and a sensitivity analysis was performed on tensile strength, a key factor in the damage model for gas movement phenomenon. In the validation study, the proposed model successfully simulated the key features observed in the test: rapid stress and pressure increase trends, changes in intrinsic permeability due to damage, and the resulting flow rate. In addition, the effect of heterogeneity on the strength characteristics of each material and interfaces between materials was analyzed through field-scale test simulations, and the applicability of the model to upscaling analysis was examined. The study of heterogeneity effects confirmed that incorporating the strength characteristics of interfaces accurately simulates the gas flow path observed in actual tests. However, the model overestimated the gas flow before the gas breakthrough and underestimated the evolution of the damaged area within the buffer. Therefore, additional research on relative permeability and mechanical constitutive models is needed to improve the reliability of the current model.

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引用次数: 0

Modelling of mass transport in fractured crystalline rock using velocity interpolation and cell-jump particle tracking methods 利用速度插值法和单元跳跃颗粒跟踪法建立碎裂结晶岩质量输运模型

IF 3.3 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2024-11-23 DOI: 10.1016/j.gete.2024.100615

Chieh-Chun Chang , Yi-Fu Chiou , Yu-Hsiang Shen , Yun-Chen Yu

In this study, two particle tracking methods, velocity interpolation, and cell-jump, were employed to simulate tracer transport in fractured crystalline rock. The models, belonging to DECOVALEX-2023 Task F1, included one considering only the influence of deterministic (major) fractures, and another considering both deterministic and stochastic (background) fractures. The simulations involved converting fracture properties into equivalent hydraulic parameters for each three-dimensional grid, simulating steady-state flow fields, and evaluating transport parameters using particle tracking methods. Using transport parameters, one-dimensional transport pathways were simulated for evaluating mass transport of tracers considering non-reactive, decay, and adsorption. Moment analysis was then utilized to quantify breakthrough curves and compare the performance of the two particle tracking methods. The conclusion is that the cell-jump method, despite facing issues with numerical dispersion that results in a broader distribution of particle trajectories, demonstrates advantages in providing relative shorter mean breakthrough times and less temporal spreading compared to the velocity interpolation (VI) method in cases involving stochastic background fractures. Both methods are limited by the issue of particles entering the matrix due to the application of non-zero permeability for numerical convenience.

在这项研究中，采用了速度内插法和单元跳跃法这两种粒子跟踪方法来模拟裂缝结晶岩中的示踪剂运移。这些模型属于 DECOVALEX-2023 任务 F1，其中一个模型只考虑确定性（主要）裂缝的影响，另一个模型同时考虑确定性和随机性（背景）裂缝的影响。模拟包括将断裂属性转换为每个三维网格的等效水力参数，模拟稳态流场，并使用颗粒跟踪方法评估运移参数。利用迁移参数，模拟了一维迁移路径，以评估示踪剂的质量迁移，其中考虑了非反应、衰变和吸附等因素。然后利用矩量分析来量化突破曲线，并比较两种粒子追踪方法的性能。结论是，尽管细胞跳跃法面临数值分散的问题，导致粒子轨迹分布较广，但在涉及随机背景裂缝的情况下，与速度插值法（VI）相比，细胞跳跃法在提供相对较短的平均突破时间和较少的时间扩散方面具有优势。这两种方法都受到颗粒进入基质问题的限制，原因是为了数值计算方便而采用了非零渗透率。

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引用次数: 0

Numerical modeling of hydro-mechanical processes during hydraulic testing of pre-existing fractures at the Grimsel Test Site, Switzerland 瑞士格里姆塞试验场对已有裂缝进行水力测试期间水力机械过程的数值建模

IF 3.3 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment

Pub Date : 2024-11-04 DOI: 10.1016/j.gete.2024.100608

Josselin Ouf , Kavan Khaledi , Philip J. Vardon , Wen Luo , Mohammadreza Jalali , Florian Amann

This study presents a fully coupled hydro-mechanical framework for modeling hydraulic shearing in a mesoscale reservoir located at the Grimsel Test Site, Switzerland. The experiment was conducted on a ductile–brittle fault embedded in low-permeable granite. We observe that normal fracture opening increases flow channel recoverably, while fracture sliding locks asperities leading to a non-recoverable increase in flow. To couple these processes, we use a poro-elasto-plastic constitutive framework and employ a permeability function that depends on several parameters, such as dilation angle, in-situ stresses, residual aperture and maximum aperture. Our results capture the recorded pressure responses well, and indicate that the permeability changes by one order of magnitude during the experiment.

本研究提出了一个完全耦合的水力机械框架，用于模拟位于瑞士格里姆塞试验场的中尺度水库的水力剪切。实验在嵌入低渗透花岗岩的韧性-脆性断层上进行。我们观察到，正常的断裂张开会增加可恢复的流道，而断裂滑动会锁定尖角，导致不可恢复的流量增加。为了将这些过程结合起来，我们使用了孔弹性塑性构造框架，并采用了取决于多个参数（如扩张角、原位应力、残余孔径和最大孔径）的渗透率函数。我们的结果很好地捕捉到了记录的压力响应，并表明在实验过程中渗透率会发生一个数量级的变化。

引用次数: 0