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1.
Lars Troldborg Jens Christian Refsgaard Karsten Høgh Jensen Peter Engesgaard 《Hydrogeology Journal》2007,15(5):843-860
Four different conceptual models based on alternative geological interpretations were formulated for a shallow 600 km2 aquifer system in Denmark comprising Quaternary deposits. Each of the four models was calibrated against groundwater heads and discharge measurements through inverse modeling. Subsequently, the transport capabilities of the four models were compared to 32 concentration measurements of environmental tracers (tritium 3H, helium-3 3He, chlorofluorocarbons CFC11, CFC12 and CFC113). The flow simulations showed only minor differences in spatial head distribution associated with alternative conceptualizations despite the complexity of the aquifer system and the significant differences in geological interpretations. The models, however, showed major differences in predictions of the age of the groundwater and environmental tracer concentrations, differences that are seen as an effect of model structure uncertainty, because no additional calibrations to these data were performed. A single conceptualization may be adequate in characterizing the natural behavior of a field system after calibration, because the calibration procedure is able to compensate for errors in the data or in the conceptual model through biased parameter values. However, once extrapolation beyond the calibration base is attempted, different conceptual model formulations result in significantly different results. Consequently, it is crucial to take model conceptual uncertainty into account when making predictions beyond the calibration base. 相似文献
2.
The transition between European and Adriatic crust is an important feature related to the plate collision that formed the European Alps. The diversity of seismic and geological information allows the construction of two alternative 3D density models, which both match the observed gravity field. Different seismic experiments suggest a thickness for the Adriatic crust between 30 and 40 km. The thick crust model requires an unusually dense lower crust (>3050 kg/m3) to reproduce the observed Bouguer anomaly. To evaluate the two alternative models, the isostatic implications of the geometry and density distribution within both 3D models are investigated, using local (Airy) and regional (Vening Meinesz) isostasy.Airy isostatic investigations show that the Eastern Alps are not isostatically compensated and the residuals correlate strongly with exposed geological formations. Subsequently, subsurface loading is an important factor controlling isostatic processes. The different geometry and densities in the two 3D models imply different loading at the crust–mantle boundary. The subsurface loads calculated from the 3D density models were used to estimate regional isostasy by a convolution method. In general, small rigidity values (D<10×1021 Nm) are determined for the Eastern Alpine lithosphere. In the model with a 40-km-thick Adriatic crust, high flexural rigidities are inferred for the Adriatic plate (>100×1021 Nm), but these values are unusual for an active orogenic region. The results point to the interfingering of European and Adriatic crust that results in the squeezing of European crust between Adriatic crust and mantle with additional contamination by mantle material. 相似文献
3.
《地学前缘(英文版)》2022,13(6):101435
The past two decades have seen a rapid adoption of artificial intelligence methods applied to mineral exploration. More recently, the easier acquisition of some types of data has inspired a broad literature that has examined many machine learning and modelling techniques that combine exploration criteria, or ‘features’, to generate predictions for mineral prospectivity. Central to the design of prospectivity models is a ‘mineral system’, a conceptual model describing the key geological elements that control the timing and location of economic mineralisation. The mineral systems model defines what constitutes a training set, which features represent geological evidence of mineralisation, how features are engineered and what modelling methods are used. Mineral systems are knowledge-driven conceptual models, thus all parameter choices are subject to human biases and opinion so alternative models are possible. However, the effect of alternative mineral systems models on prospectivity is rarely compared despite the potential to heavily influence final predictions. In this study, we focus on the effect of conceptual uncertainty on Fe ore prospectivity models in the Hamersley region, Western Australia. Four important considerations are tested. (1) Five different supergene and hypogene conceptual mineral systems models guide the inputs for five forest-based classification prospectivity models model. (2) To represent conceptual uncertainty, the predictions are then combined for prospectivity model comparison. (3) Representation of three-dimensional objects as two-dimensional features are tested to address commonly ignored thickness of geological units. (4) The training dataset is composed of known economic mineralisation sites (deposits) as ‘positive’ examples, and exploration drilling data providing ‘negative’ sampling locations. Each of the spatial predictions are assessed using independent performance metrics common to AI-based classification methods and subjected to geological plausibility testing. We find that different conceptual mineral systems produce significantly different spatial predictions, thus conceptual uncertainty must be recognised. A benefit to recognising and modelling different conceptual models is that robust and geologically plausible predictions can be made that may guide mineral discovery. 相似文献
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5.
为了解决矿井导水构造精细刻画与三维地质模型灵活继承中存在的陷落柱内部岩石结构刻画不精细、多源数据融合不准确等技术问题,开展了矿井导水构造多源数据融合实体模型构建方法、精细模型构建过程与模型转换系统开发等方面的研究。基于数据融合分布式结构理论,采用地质数据耦合、实体模型耦合和构建模式耦合3个层次的耦合策略,建立一套水文地质勘探多源数据融合为三维地质实体模型的构建方法,通过多源异构地质数据标准化预处理、跟踪与分类、数据配准、关联与融合等4个关键步骤,构建矿井导水构造多源数据融合实体模型。在地质统计学研究的基础上,以陷落柱为例,提出“矿井精细导水构造模型”与“广域概略模型”的基本概念,同时构建了陷落柱广域概念模型与精细模型。根据SURPAC和FLAC3D2种三维模型的属性与数据结构特点,提出了矿井导水构造SURPAC和FLAC3D模型转换方法,利用JAVA语言和TCL语言研发了SURPAC-FLAC3D模型转换系统,该系统同时支持本地、网络操作与多用户多台机器的远程控制,最终实现了导水构造实体耦合模型转换为FLAC3D计算模型的目标,为矿山地质条件精细勘查与融合构建、矿山水害精准预测与防治提供技术支撑。 相似文献
6.
Junqi Liu Huiming Tang Junqiang Zhang Tingting Shi 《Environmental Earth Sciences》2014,72(10):3847-3856
As the global research topic, geological disasters have led to huge losses around the world yearly. In this paper, three-dimensional (3D) visualization is used as a technical method to build the 3D geological model of the HuangTuPo (HTP) landslide, and the 3D model of large field test base located in the HTP landslide, and the 3D regional geological model. These models make the landslide research digitized and transparent. Meanwhile, the preliminary studies were carried out: the comprehensive utilization of multiple scales and multiple categories of data—by “Double Center”, and the 3D data integration from region to point of disasters—by the component technology, and the transparent design and construction of disaster research—by 3D model shearing. Through these methods, the surface topography and the underground geological structure of landslide can be displayed as transparent as glass, and the virtual simulation on the results of underground engineering can be carried out in advance, providing guidance for engineering design and construction. 相似文献
7.
在基于钻孔数据进行三维地层建模方法中,钻孔样本间地层层序不一致导致建模时难以确定各地层的拓扑关系,快速准确地确定各地层层序和充分利用钻孔数据是建模的关键难点之一。拟通过综合考虑区域内所有钻孔数据,基于地质解释方法理论,以地层出现次数频率高原则进行全自动确定地层层序。首次引入子钻孔递归思想,利用表面建模方法,自下而上逐层创建三维地层模型,可确保钻孔数据不丢失且准确地应用于地层建模中,并能适应地层尖灭、地层超覆、透镜体等复杂地质构造。该方法地学意义明确,具有鲁棒性好、运行效率高及可操作性强等特点,算法已在同济曙光软件中实现,并已在多个实际地质建模工程中得到了验证。研究结果表明,该算法能充分利用已有钻孔信息,建模过程全自动完成,对复杂地层建模亦具有较强的适应性。 相似文献
8.
分块区域三维地质建模方法 总被引：3，自引：0，他引：3
区域三维地质建模是区域三维地质调查的关键。在大量反复实践的基础上,提出了分块三维地质建模方法,该方法的主要步骤为：以断裂、岩体边界和不整合等为边界,把复杂的三维地质建模区域分解为内部构造相对简单的建模块或建模地质单元;分别对各建模块进行地质地球物理综合研究,编制深部地质剖面,揭示深部地质结构;采用基于剖面的建模方法按照全区统一的坐标系统构建三维地质模型;在完成全区所有建模块三维地质模型构建之后,把各个建模块的三维地质模型集成在统一的三维空间框架下,形成全区的三维地质模型。该方法具有能够简化三维地质建模过程、易于修改完善模型、易于集成模型等优势,能够克服常规的基于剖面的三维地质建模方法中存在的问题,突破了大规模区域三维地质建模的瓶颈。在本溪-临江深部地质调查中的应用表明,采用该方法可以有效构建研究区的三维地质模型,并能充分表达复杂的地下深部地质结构,为开展复杂地区大规模区域三维地质建模提供了一个重要途径。 相似文献
9.
砂体上倾尖灭油气藏是岩性油气藏中重要类型之一,砂体上倾尖灭的刻画与描述是上倾尖灭圈闭有效性评价的关键。在以三角洲前缘沉积为主构成的三级层序内,三角洲沉积相关砂体上倾尖灭的地质-地球物理“逐级预测”描述方法对于认识上倾尖灭油气藏分布规律及其油气勘探具有重要意义。该方法由5个部分组成:在三级层序识别的基础上,运用高精度层序地层划分技术建立了四级层序构成的高频层序地层格架;在高频层序约束下,利用地震沉积学技术描述沉积相的平面分布;在地质模型指导下,利用频谱成像技术定性确定尖灭带的分布;利用相控储层反演半定量、定量预测砂体尖灭线;根据不同成因砂体的沉积特点,利用正演模拟技术开展尖灭线的外推预测。 相似文献
10.
11.
三维地质模型精度评估与误差修正问题已成为制约三维地质模拟技术深入发展应用的瓶颈。在综合国内外研究现状与发展趋势的基础上,提出了三维地质结构模型精度评估、误差检测、动态修正的总体研究框架。在模型精度评估方面,提出分别构建三维地质结构模型精度评估的一般理论模型、面向特定地质体的实际操作模型和地质结构构造不确定性的三维空间分布模型的研究思路,指出应重点研究地质实体自身特性、三维地质建模方法对三维地质结构模型精度的影响,解决由一般地质界面的内插误差和特殊地质体的外推误差引起的精度评估问题。在模型误差修正方面,提出基于建模初始数据的模型误差修正方法和基于建模中间结果的模型误差修正方法,在具体实现时,引入“数据 模型的可视化交互技术”。这些研究成果为建立一套完整的三维地质结构模型精度评估与误差修正的理论体系和方法体系奠定了基础,有助于完善复杂地质条件下三维地质模拟的方法与技术。 相似文献
12.
三维信息化模型是重大工程全生命周期建设的重要基础。然而,目前对于地质三维模型与建筑结构三维信息模型,通常由于数据结构问题难以统一,而且大部分停留在“可视化”,难以“可计算”、“可分析”。此外,由于地质条件的复杂性,在三维地质建模方面通常进行大量的简化。本文基于目前先进的三维建模技术,提出了三维精细化地质模型与建筑结构三维模型融合的建模方法,实现了三维地质模型的快速、精细化建模。所建立的模型,统一在*.stl、*.obj及*.igs等标准化三维模型文件下,可方便地用于不同场景的三维模型可视化、分析及后续数值计算模型网格划分等。针对大型水电工程建设提出了水利工程信息模型的框架,并将其应用于索风营水利工程,实现了大坝精细化BIM及4个堆积体的精细化三维地质模型(LIM)的融合与信息化管理。本文研究对于实现水电工程信息化管理、稳定性分析、潜在灾害评估和预测等具有重要的意义。 相似文献
13.
Improved seismic velocity reference model from local earthquake data in Northwestern Italy 总被引：3，自引：0，他引：3
Resolution and reliability estimates of results obtained by seismic tomography strongly depend on the reference model. Inadequate initial reference models may severely distort tomographic images or introduce artefacts that lead to misinterpretations of the results. Reference models are usually obtained by means of a priori near-surface geological information or by geophysical information derived by controlled-source seismology.
Starting from the idea that a reference model must approximate the weighted average of data selected for the three-dimensional (3D) inversion, one-dimensional (1D) model for Northwestern Italy is derived that is able to minimize mean of RMS of a set of well-locatable earthquakes, by computing a solution of the coupled hypocentre 1D velocity problem.
Such a model, termed the Minimum 1D model, can be used both as an initial reference model for 3D inversion and as a reference velocity model for high-quality routine earthquake location. 相似文献
Starting from the idea that a reference model must approximate the weighted average of data selected for the three-dimensional (3D) inversion, one-dimensional (1D) model for Northwestern Italy is derived that is able to minimize mean of RMS of a set of well-locatable earthquakes, by computing a solution of the coupled hypocentre 1D velocity problem.
Such a model, termed the Minimum 1D model, can be used both as an initial reference model for 3D inversion and as a reference velocity model for high-quality routine earthquake location. 相似文献
14.
D. Bugai A. Skalskyy S. Dzhepo Yu. Kubko V. Kashparov N. Van Meir D. Stammose C. Simonucci A. Martin-Garin 《Applied Geochemistry》2012
This article represents the second of two articles, which review the main results of the international radioecological projects: Chernobyl Pilot Site Project (1999–2003) and Experimental Platform in Chernobyl (2004–2008). These projects studied radionuclide migration from the near-surface radioactive waste trench at the Red Forest waste dump in the Chernobyl zone, which contained nuclear fuel particles. This article presents results from the comprehensive hydrogeological site characterization program including the following issues: geological structure of the study site, hydraulic properties of the deposits, tracer tests in the aquifer, results of groundwater monitoring and unsaturated zone regime studies, as well as data on the 90Sr distribution in the unsaturated zone and aquifer, and analyses of 90Sr sorption behavior. The derived parameters were used to develop and calibrate 1D (flow tube) and 2D (cross-section) models describing the migration of 90Sr from the studied waste trench to the unsaturated zone and aquifer over a 16-a period (1986–2002). The models involved the following sub-models: (1) the geostatistical (structural) model for radioactivity distribution in the trench (using GSLIB); and (2) the radionuclide source term model (STERM1D) describing dissolution of fuel particles and a 1D of radionuclide redistribution in the trench body and unsaturated zone. The MODFLOW – MT3D codes were used to model the 2D 90Sr transport in the aquifer cross-section. Calibration of the 1D model with respect to Kds and dispersivities allowed quite accurate reproduction of 90Sr migration behavior for the early period (1995–1998). The less perfect fit between the 1D and 2D modeling results and monitoring data for the later period (1999–2002) suggests the need to improve the conceptual radionuclide migration model (i.e. to account for transient hydraulic and geochemical regimes of the waste site). 相似文献
15.
真实地质体三维数值模型构建是进行岩体工程数值分析面临的难题,开展大型复杂地质体三维数值模型构建方法比较研究具有重要意义。以3DMine数字化模型为基础,提出了3DMine-FLAC3D耦合建模方法和3DMine-Surfer-Rhino- ANSYS-FLAC3D多软件耦合建模方法,详细阐述了各建模方法具体步骤,深入分析了各建模方法优缺点及适用性,通过对比各建模方法的优势与短板,取长补短,改进了3DMine-FLAC3D耦合建模方法存在的缺陷,解决了复杂地质体三维数值模型构建难题。以广西铜坑矿锌多金属矿体开采为背景,利用大型复杂地质体三维数值建模方法,构建了锌多金属矿三维数值模型,分析了矿体上行开采地表沉陷规律。研究成果对准确构建大型复杂地质体三维数值模型具有重要指导作用。 相似文献
16.
Hysteresis effects in geological CO2 sequestration processes: A case study on Aneth demonstration site,Utah, USA 
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下载免费PDF全文 Realistic models for saturation, capillary pressure and relative permeability s-pc-kr relations are essential for accurate predictions in multiphase flow simulations. The primary object of this work is to investigate their influence on geological CO2 sequestration processes. In this work, the hysteresis effects on simulation results predicting geological CO2 storage are investigated on a synthetic 2D model and a geological setting built according to Aneth demonstration site. Simulation results showed that hysteretic relative permeability model should be included while the residual trapping mechanism is under investigation. The effects of hysteresis and WAG schemes were studied with a series of numerical simulations on a geological setting based on Aneth site. Our simulations demonstrate that the hysteresis effect is strong on residual trapping mechanisms and there is no significant effects of alternative WAG schemes for long term residual trapping in our conceptual model. The effects of WAG schemes and hysteresis are weak on dissolution trapping mechanisms. 相似文献
17.
在深部找矿过程中,三维地质建模技术起着不可或缺的作用。本次研究以相山矿田横涧-岗上英矿区为例,依托成矿理论、成矿预测理论和矿产资源勘查与评价理论,分析总结横涧-岗上英矿区的成矿地质条件,利用三维地质建模软件GoCAD建立研究区的地形、地层、构造、岩体、矿体和钻探模型,进一步结合勘查开采经验,建立矿区的地质找矿模型,并且采用找矿信息量法圈定成矿有利区段3处。结果表明,横涧-岗上英矿区深部仍有较大的找矿潜力。 相似文献
18.
Teti Zubaidah M. Korte M. Mandea Y. Quesnel B. Kanata 《International Journal of Earth Sciences》2010,99(5):1123-1132
During the last years, several investigations on the earthquakes and related tectonic structures along the Java Trench have
been conducted. In this study, we focus on the Lombok Island—West Nusa Tenggara (Indonesia), which lies between the centres
of the highest intensity of contiguous negative–positive geomagnetic anomalies in this region. The geological and tectonic
structures, however, are not known in detail for this island, whereas a better knowledge of these conditions could lead to
better estimate the potential earthquake risks and thus a possible improvement of the existing early warning system. We have
performed a ground-based geomagnetic survey at 56 stations in the Lombok Island during October–November 2006 for a detailed
mapping and interpretation of geomagnetic anomalies related to the geological and tectonic characteristics. The 2D and 3D
magnetic maps show a general geomagnetic anomaly pattern in the Lombok Island which consists of repeated contiguous negative–positive
anomalies. Two forward models have been proposed for a profile connecting a strongest apparent dipolar structure. The first
model assumes a uniformly magnetized sphere as the source of the anomaly, and could be interpreted as a specific local structure
composed by a quite large magnetic body. The second model considers several rocks with different susceptibilities and magnetizations,
and could be interpreted as a discontinuity in the geological structures. This model agrees with the local geological surface
conditions and the known large scale regional tectonic structure. Therefore, it is used to interpret our results in terms
of tectonic characteristics, which suggests the potential existence of a new tectonic element (e.g. a local normal fault)
in this region. 相似文献
19.
A. K. Verma R. K. Bajpai T. N. Singh P. K. Narayan Avi Dutt 《Arabian Journal of Geosciences》2011,4(7-8):1173-1188
Conceptual geological repositories are generally used for disposing spent nuclear wastes containing both high and low level of nuclear radiation and heat. Due to its long-lasting effect, it is imperative to analyze its long-term effect on the surrounding rock. Before analyzing radiation and thermal effect, it is important to have structurally stable cavern because designing an opening in rock is a more difficult problem than designing the structure made of steel. Underground rocks are under stress because of the weight of the overlying rock, and in addition, an underground opening will produce a stress concentration and stress relaxation in the surrounding rock. If the induced stress in the surrounding rock exceeds its strength, the opening will fail either by fracturing or by deforming more than the tolerable limit. In this paper, the stability of four different shapes of excavation has been examined for conceptual geological repositories in Indian context. This has been done using equivalent continuum numerical model which has been incorporated in the commercial finite difference code-FLAC-3D. Effects of opening shapes on stress distribution, subsidence of crown and side wall, and their stability have been analyzed and discussed. The validation of FLAC3D software for its applicability in conceptual underground geological repositories has been done with a published literature. 相似文献
20.
The Zhonggu iron orefield is one of the most important iron orefields in China, and is located in the south of the Ningwu volcanic basin, within the middle and lower Yangtze metallogenic belt of eastern China. Here, we present the results of new 3D prospectivity modeling that enabled the delineation of areas prospective for exploration of concealed and deep-seated Baixiangshan-type mineralization and Yangzhuang-type mineralization within the Zhonggu orefield; both of these deposits are Kiruna-type Fe-apatite deposits but are hosted by different formations within the Ningwu Basin. The modeling approach used during this study involves 3 steps: (1) combining available geological and geophysical data to construct 3D geological models; (2) generation of 3D predictive maps from these 3D geological models using 3D spatial analysis and 3D geophysical methods; (3) combining all of the 3D predictive maps using logistic regression to create a prospectivity map. This approach integrates a large amount of available geoscientific data using 3D methods, including 3D geological modeling, 3D/2D geophysical methods, and 3D spatial analysis and data integration methods. The resulting prospectivity model clearly identifies highly prospective areas that not only include areas of known mineralization but also a number of favorable targets for future mineral exploration. The 3D prospectivity modeling approach showcased within this study provides an efficient way to identify camp-scale concealed and deep-seated exploration targets and can easily be adapted for regional- and deposit- scale targeting. 相似文献