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Hussein Mustapha 《Computational Geosciences》2011,15(3):385-397
We present G23FM, a mesh generation tool for discretizing two- and three-dimensional complex fractured geological media. G23FM
includes different techniques to generate finite element grids that maintain the geometric integrity of input surfaces, and
geologic data and produce optimal triangular/tetrahedral grids for flow and transport simulations. G23FM generates grid for
two-dimensional cross-sections, represents faults and fractures, for three-dimensional fractured media, and has the capability
of including finer grids. Different examples are presented to illustrate some of the main features of G23FM. 相似文献
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刘亚晨 《地质灾害与环境保护》2006,17(2):78-82
针对上期论文对核废料贮存围岩介质THM耦合过程的力学分析建立的数学模型,本文推导了求解THM耦合力学模型的有限元计算公式,并编制了有限元计算程序,并用BM T 1问题的算例,探讨了核废料贮存裂隙岩体水热耦合迁移以及应力响应特征。 相似文献
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V. S. Ponomarev 《Geotectonics》2011,45(2):157-165
Deformations of the geologic medium are traditionally regarded as a result of the application of external forces. At the same
time, such deformations can be realized at the expense of energy sources contained in the deformed bodies themselves. Since
the idea of energetic inactivity of the medium dominates as an organizing center of scientific research in this field, it
blocks the study of media in the state of energetic activity. The work discusses possible ways to overcome this conflict on
the basis of specific examples. 相似文献
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Hydromechanical coupling in geologic processes 总被引：6，自引：2，他引：4
Earth's porous crust and the fluids within it are intimately linked through their mechanical effects on each other. This paper
presents an overview of such "hydromechanical" coupling and examines current understanding of its role in geologic processes.
An outline of the theory of hydromechanics and rheological models for geologic deformation is included to place various analytical
approaches in proper context and to provide an introduction to this broad topic for nonspecialists.
Effects of hydromechanical coupling are ubiquitous in geology, and can be local and short-lived or regional and very long-lived.
Phenomena such as deposition and erosion, tectonism, seismicity, earth tides, and barometric loading produce strains that
tend to alter fluid pressure. Resulting pressure perturbations can be dramatic, and many so-called "anomalous" pressures appear
to have been created in this manner. The effects of fluid pressure on crustal mechanics are also profound. Geologic media
deform and fail largely in response to effective stress, or total stress minus fluid pressure. As a result, fluid pressures
control compaction, decompaction, and other types of deformation, as well as jointing, shear failure, and shear slippage,
including events that generate earthquakes. By controlling deformation and failure, fluid pressures also regulate states of
stress in the upper crust.
Advances in the last 80 years, including theories of consolidation, transient groundwater flow, and poroelasticity, have been
synthesized into a reasonably complete conceptual framework for understanding and describing hydromechanical coupling. Full
coupling in two or three dimensions is described using force balance equations for deformation coupled with a mass conservation
equation for fluid flow. Fully coupled analyses allow hypothesis testing and conceptual model development. However, rigorous
application of full coupling is often difficult because (1) the rheological behavior of geologic media is complex and poorly
understood and (2) the architecture, mechanical properties and boundary conditions, and deformation history of most geologic
systems are not well known. Much of what is known about hydromechanical processes in geologic systems is derived from simpler
analyses that ignore certain aspects of solid-fluid coupling. The simplifications introduce error, but more complete analyses
usually are not warranted. Hydromechanical analyses should thus be interpreted judiciously, with an appreciation for their
limitations. Innovative approaches to hydromechanical modeling and obtaining critical data may circumvent some current limitations
and provide answers to remaining questions about crustal processes and fluid behavior in the crust.
Electronic Publication 相似文献
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本文对无限空间二维变化粘弹介质中的高斯束及有关过界面的情况进行了讨论。在讨论中发现,利用高斯束法既可不用定点射线追踪,还可保证处处规则,较近年来发展较快的标准射线方法有很大的灵活性,适于处理各种复杂地质情况。并对理论地震记录的合成方法作了简要介绍。 相似文献
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未开采煤层瓦斯含量及影响因素研究,是煤矿安全生产的重要基础研究工作,以铁法盆地晓南矿未开采的14#煤层为例,系统分析了影响瓦斯含量的地质因素。采用灰色关联方法,对各影响因素进行研究,建立了灰色关联模型,并计算出各影响因素的关联度。研究结果表明：影响晓南矿14#煤层瓦斯含量的主要地质因素有煤的变质程度、地质构造、煤层厚度及煤层埋深等。并用多元回归对其进行了瓦斯含量预测。这为未开采煤层瓦斯含量的研究提供了科学方法,并为该煤矿的安全开采提供了基础资料。 相似文献
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A literature review of dripping in underground constructions in deep, unsaturated geologic media was performed as part of
a phased study. The objective is to develop and test a formulation that can be used for studying unsaturated flow through
rough multi-segmented fractures, with emphasis on predicting dripping initiation time. Geologic and hydrogeologic setting
for the Yucca Mountain (YM) and its exploratory studies facility, which is the site where the model will be tested, are described. 相似文献
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Construction of predictive reservoir models invariably involves interpretation and interpolation between limited available data and adoption of imperfect modeling assumptions that introduce significant subjectivity and uncertainty into the modeling process. In particular, uncertainty in the geologic continuity model can significantly degrade the quality of fluid displacement patterns and predictive modeling outcomes. Here, we address a standing challenge in flow model calibration under uncertainty in geologic continuity by developing an adaptive sparse representation formulation for prior model identification (PMI) during model calibration. We develop a flow-data-driven sparsity-promoting inversion to discriminate against distinct prior geologic continuity models (e.g., variograms). Realizations of reservoir properties from each geologic continuity model are used to generate sparse geologic dictionaries that compactly represent models from each respective prior. For inversion initially the same number of elements from each prior dictionary is used to construct a diverse geologic dictionary that reflects a wide range of variability and uncertainty in the prior continuity. The inversion is formulated as a sparse reconstruction problem that inverts the flow data to identify and linearly combine the relevant elements from the large and diverse set of geologic dictionary elements to reconstruct the solution. We develop an adaptive sparse reconstruction algorithm in which, at every iteration, the contribution of each dictionary to the solution is monitored to replace irrelevant (insignificant) elements with more geologically relevant (significant) elements to improve the solution quality. Several numerical examples are used to illustrate the effectiveness of the proposed approach for identification of geologic continuity in practical model calibration problems where the uncertainty in the prior geologic continuity model can lead to biased inversion results and prediction. 相似文献
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Automatic analysis of geological structure from dip-strike data 总被引：1，自引：0，他引：1
We present a technique to analyze dip-strike data to estimate a geologic structure in a previous study, in which some technical and geological problems are left unsolved. In this study, we have solved some geological problems which are to take the lateral discontinuity of the structure into account and use levels of bedding plane as input data. And also, we tried to extend the technique to more general problems that the structure consists of vertically different geologic units. We show the technique revised and some artificial and actual examples analyzed to check its validity and applicability. 相似文献
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The aim of the study is to increase the reliability of estimation of the acoustic parameters of a layered permeable formation using new software, based on two-velocity continuum equations for 2D numerical simulation of acoustic waves propagating in a borehole. The key method is the method of finite differences as applied to solving equations of the continuum filtration theory. The dissipative characteristics of Stoneley waves have been identified for the case of their propagation in a layered formation. These aspects should be taken into account when using Stoneley waves to estimate the permeability of geologic media. 相似文献
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井地联合并行电法通过在井孔和地面布设电极,进行全电极供电和测量,获得钻孔周边地电场分布特征,研究储层介质结构及变化特征,对地下复杂地电模型分辨具有重要作用。文章通过构建室内井地电法测试模型,采用并行电法技术,三维反演介质的电阻率,判断井孔周边不同类型地质体的异常分布特征。结合野外井地条件进行实测,结果表明,通过井地联合测试系统可以对钻孔周边地质条件进行有效分辨,为储层介质探查与判断提供辅助依据。 相似文献
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A new and simple concept based on the idea of correcting for non-associative characteristics of (geologic) media is presented. A special form of the concept is adopted and introduced in a critical state plasticity model. An example problem of behaviour of a soil tested under triaxial conditions is included. The concept can permit a simplified treatment of non-associativeness and under certain assumptions can allow use of existing formulations of plasticity by maintaining symmetry of the associated matrices. 相似文献
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We use high resolution Monte Carlo simulations to study the dispersive mixing in two-phase, immiscible, porous media flow that results from the interaction of the nonlinearities in the flow equations with geologic heterogeneity. Our numerical experiments show that distinct dispersive regimes occur depending on the relative strength of nonlinearity and heterogeneity. In particular, for a given degree of multiscale heterogeneity, controlled by the Hurst exponent which characterizes the underlying stochastic model for the heterogeneity, linear and nonlinear flows are essentially identical in their degree of dispersion, if the heterogeneity is strong enough. As the heterogeneity weakens, the dispersion rates cross over from those of linear heterogeneous flows to those typical of nonlinear homogeneous flows. 相似文献
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A five-step procedure involving mathematical formulation, identification and determination of parameters and verification is presented for development and selection of appropriate and reliable constitutive law(s) for geologic media. Comprehensive analyses are performed toward determination of an appropriate law for a (artificial) soil. The most suitable model is obtained by critical evaluation of four different plasticity models; here verification and comparisons of predictions with observations from laboratory tests, and with those from two boundary value problems are used as the basis of the selection. The model thus selected is found to be appropriate for applications to relevant practical problems. 相似文献
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地质体综合是地质图编制工作的重中之重,因其处理涉及内容多、业务逻辑复杂、重复工作量大,是影响编图工作推进的主要因素。为了能够实现地质体的高效综合,文章提出了一种以地质约束条件(专家知识)为核心、以制图综合为空间图形合并手段的新型地质体智能综合方法,设计并实现了围绕地质专家知识(如地质年代、地层名称等)规则映射开展的三种地质体综合方法(同属性合并、交互式选择合并、绘图合并)。使用北山地区地质图数据对地质体综合模块进行测试,经反复对比实验,证实了该方法不仅能够快速实现地质体空间图形的"一键式"合并,还可以自动完成地质知识的映射与赋值,综合结果符合地质规律。该方法为反映地质空间分布前提下对图件中地质体或其他面图元的精简提供了一种有效的自动化工具。 相似文献
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We present an extended finite element (FE) approach for the simulation of slow‐rate frictional faulting in geologic media incorporating bulk plasticity and variable friction. The method allows the fault to pass through the interior of FEs without remeshing. The extended FE algorithm for frictional faulting, advocated in two recent articles, emanates from a variational equation formulated in terms of the relative displacement on the fault. In the present paper we consider the combined effects of bulk plasticity and variable friction in a two‐dimensional plane strain setting. Bulk plasticity is localized to the fault tip and could potentially be used as a predictor for the initiation and propagation of new faults. We utilize a variable velocity‐ and state‐dependent friction, known as the Dieterich–Ruina or ‘slowness’ law, formulated in a slip‐weakening format. The slip‐weakening/variable friction model is then time‐integrated according to the generalized trapezoidal rule. We present numerical examples demonstrating the convergence properties of a global Newton‐based iterative scheme, as well as illustrate some interesting properties of the variable friction model. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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二维密度界面的遗传算法反演 总被引：8，自引：0，他引：8
二维密度界面的反演可表述成非线性优化问题，本文用遗传算法进行反演计算，首先把连续的密度界面分割成若干单元，在单元中用形函数拟合，再用高斯积分求解重力异常值，把约束条件和拟合方差组合成目标函数，用园柱体和二维盆地模型的反演实例表明，用遗传算法，反演二维密度界面是可行的 相似文献
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Semantic Web technologies bring innovative ideas to computer applications in geoscience. As an essential part of the Semantic Web, ontologies are increasingly discussed in the geoscience community, in which geologic time scale is one of the topics that have received the most discussion and practices. This paper aims to carry out a review of the recent progress on geologic time ontologies, discuss further improvements, and make recommendations for other geoscience ontology works. Several models and ontologies of geologic time scale are collected and analyzed. Items such as ontology evaluation, ontology mapping, ontology governance, ontology delivery and multilingual labels are discussed for advancing the geologic time ontologies. We hope the discussion can be useful for other geoscience ontology works, and we also make a few further recommendations, such as referring to an ontology spectrum in ontology creation, collaborative working to improve interoperability, and balancing expressivity, implementability and maintainability to achieve better applications of ontologies. 相似文献