基于多源、 多时相遥感影像的高原湖泊提取及其不确定性——以西藏羊卓雍错流域为例

基于野外实地考察, 以西藏中南部羊卓雍错流域为例, 探讨了基于多源、 多时相遥感影像的高原湖泊提取. 目前计算机辅助分类方法在高原湖泊提取上存在很大的局限性, 目视解译方法虽然繁琐, 但能结合丰富的经验信息, 故而成为当今高原湖泊提取的较为现实与可行的方法. 为此, 针对各季湖面特征的不同相态, 结合图像增强技术、 DEM等辅助信息和野外实地验证, 建立了高原湖泊不同时相的遥感解译标志. 根据1972-2009年Landsat、 CBERS和HJ-1A/1B等3种不同数据源的37幅遥感影像提取了流域内主要湖泊, 并分析了湖泊面积的年内与年际变化. 在此基础上, 讨论了高原湖泊提取过程的不确定性, 包括遥感影像甄选、 几何校正误差、 数字化容差和目视解译经验等给结果带来的不确定性. 结果表明: 引入高分辨率、 多源遥感影像以及不受天气状况影响的微波影像有助于高原湖泊变化监测能力与解译精度的提高; 而综合考虑地形信息、 湖泊不同时相特征, 适用于多种数据源的计算机自动解译算法研发, 将提高长时间序列高原湖泊提取的效率.     

Geomechanical property estimation of unconventional reservoirs using seismic data and rock physics

An extension of a previously developed rock physics model is made that quantifies the relationship between the ductile fraction of a brittle/ductile binary mixture and the isotropic seismic reflection response. By making a weak scattering (Born) approximation and plane wave (eikonal) approximation, with a subsequent ordering according to the angles of incidence, singular value decomposition analyses are performed to understand the stack weightings, number of stacks, and the type of stacks that will optimally estimate two fundamental rock physics parameters – the ductile fraction and the compaction and/or diagenesis. It is concluded that the full PP stack, i.e., sum of all PP offset traces, and the “full” PS stack, i.e., linear weighted sum of PS offset traces, are the two optimal stacks needed to estimate the two rock physics parameters. They dominate over both the second‐order amplitude variation offset “gradient” stack, which is a quadratically weighted sum of PP offset traces that is effectively the far offset traces minus the near offset traces, and the higher order fourth order PP stack (even at large angles of incidence). Using this result and model‐based Bayesian inversion, the seismic detectability of the ductile fraction (shown by others to be the important rock property for the geomechanical response of unconventional reservoir fracking) is demonstrated on a model characteristic of the Marcellus shale play.     

基于多源遥感数据分析日喀则地区活动断裂的影像特征

选取多时相、多波段的MODIS红外影像以及MSS、ETM、资源卫星等多源遥感数据,通过解译活动断裂的遥感影像标志,对西藏日喀则地区东西向的活动断裂位置及其活动性进行了重新解译和判定,识别出了沿雅鲁藏布江缝合带展布的三条活动断裂,即冈底斯断裂、昂仁-仁布断裂、拉孜-邛多江断裂。同时,利用多源遥感影像综合分析了断裂发育的宏观及微观地貌特征,研究了构造活动与水系冲沟地貌之间的关系,得到了一些初步认识:三条东西向活动断裂以挤压逆冲为主,且受雅鲁藏布江缝合带的控制,断裂的活动性存在差异;利用亮温梯度特征在红外影像上提取的线性迹象与光学影像提取的活动断裂位置吻合较好;红外亮温梯度的变化除了受季节、地形、地貌等多种因素影响外,可能还与断裂的活动性有关。在传统遥感解译活动断裂的基础上,辅以红外亮温梯度特征分析,有助于更好地开展活动断裂的提取及其活动性监测研究工作。     

地质雷达在活动断裂探测中的应用与进展

结合国内外最新研究成果,对地质雷达技术在活动断裂探测中的应用进行了系统分析和总结,重点对地质雷达在城市活断层探测、古地震探测和断层识别方法的研究现状进行了阐述,并结合理塘活动断裂的应用实例进行评述。最后,提出了地质雷达探测活动断裂现存的问题,对该技术探测活动断裂的发展方向和应用前景进行了展望。      

遥感解译在内蒙古狼山戈壁荒漠地区1:50000地质填图中的应用

针对内蒙古戈壁荒漠区特殊地貌地质填图工作,选择ASTER和SPOT5数据,通过图像融合、影像校正、影像增强等处理方法,提高图像的空间分辨率和光谱分辨率。利用遥感解译图像快速准确地获取地层、侵入体和构造的解译标志,通过遥感地质解译结合地面调查进行综合分析和解译,提高了填图的准确性,为特殊地质地貌区地质填图提供技术支持,对于在同类区域开展地质填图工作有指导意义。      

一种基于地球物理数据格网的三维地质填图方法及其实现

地球物理方法（重力、地震、电法等）是地质调查及填图工作中的重要手段。相对于二维地质填图,三维地质填图/建模更迫切地需要借助地球物理数据来获取大量与深度有关的地质信息,因此本文提出了一种基于地球物理数据的地质体三维填图方法。首先,将不同地球物理手段所获取到的数据格网进行可视化建模综合;然后,在有限的地质采样约束下进行解释并直接映射为地质三维模型。实践证明,该方法自动化程度较高,并能在地质调查工作中针对性地解决一些地球物理资料较丰富而地质采样相对匮乏的三维地质填图问题。此外,它也可应用于传统三维地质填图工作中,以极大地提高地球物理数据处理效率。     

遥感技术在矿产远景调查工作中的应用——以内蒙古莫力达瓦旗巴彦街地区为例

工作区所在的大兴安岭北段地区,由于地面披覆物的影响,地质体在遥感影像上的区分度降低,一般认为遥感技术难以发挥作用.但是对矿调工作来说,抓住与矿产分布最为密切的线、环形构造和遥感蚀变异常两方面的内容最为关键,而这两方面的内容受地面披覆物的影响相对较小.在巴彦街矿调项目中,首先对工作区进行不同尺度的线、环形构造解译,运用比值-主成分分析方法提取蚀变异常.综合两方面的内容,并结合化探异常圈定了重点工作区,经探槽工作验证,具有较好的找矿前景.     

Facies and seismic analysis of the Late Carboniferous–Early Permian Finnmark carbonate platform (southern Norwegian Barents Sea): An assessment of the carbonate factories and depositional geometries

The late Palaeozoic buried Finnmark platform, in the Norwegian Barents Sea, is a depositional system which developed under major modifications of palaeoclimatic and palaeoceanographic conditions, given by the northward drifting of the Arctic depositional domain beyond the tropical belt, the activity of the Gondwanan icecaps, and the gradual closure of the Eastern European seaway. In this study, detailed core/microfacies analysis from the explorations wells 7128/4-1 and 7128/6-1, combined with new 2D seismic sections and available dataset from previous studies in the eastern Finnmark area, have allowed a re-evaluation of the depositional scenarios associated with the Ørn and Isbjørn/Polarrev Formations. The late Asselian–early Sakmarian depositional record of the Ørn Formation, followed by the middle Sakmarian transition to the Isbjørn/Polarrev Formations, shows depth-related variations in sedimentation modes and a change of the platform morphology.In particular, a shift from Chloroforam to Bryonoderm sedimentation mode took place through a stratified water column during the deposition of the Ørn Formation, over what we suggest was a distally steepened ramp. In the late Sakmarian, the deposition of the Isbjørn/Polarrev Formations, characterised by a full Bryonoderm sedimentation mode, took place through a cooler non stratified water column, leading to the gradual instauration of a homoclinal ramp profile.Among the other results, our integrated study suggests the development of subtidal heterozoan mounds associated with the Ørn Formation, predating the formation of the larger, stacked and well-known heterozoan distal complexes of the Polarrev Formation. Given the good potential of the Ørn Formation within the Finnmark depositional domain, our results may help to improve the assessment of future evaluations of reservoir properties in the area, which are closely associated with the depositional style and their post-depositional modifications.     

Seal rock deformation by polygonal faulting,offshore Uruguay

Due to a lack of borehole data, reservoir and seal rock presence in frontier basins is typically inferred from seismic reflection data. However, analysis of the geometry and kinematic development of polygonal fault systems (PFS), which almost exclusively form within very fine-grained strata, provides another, largely untested method to infer reservoir and seal rock presence. We here use very high-quality 3D seismic reflection data from offshore Uruguay and a range of quantitative GIS-based techniques to document the planform and cross-sectional characteristics of a basin-scale (>6400 km²) PFS, and to investigate the role that stratigraphic variations in the Tertiary deep-water host-rock have on its geometrical variability and kinematic development. We demonstrate that a series of likely sandstone-rich deep-water deposits occur at the base of and within the main PFS tier. The geometric characteristics and throw distribution on individual polygonal faults suggest these sandstone-rich deep-water deposits represent a mechanical barrier to fault propagation, thus influencing fault height and areal density and, in some cases, strike. We argue that in largely unexplored, deep-to ultra-deep water basins, such as those characterizing offshore Uruguay, the distribution and geometric attributes of PFS can be used to delineate sandstone-rich reservoir bodies. Furthermore, these characteristics may help exploration geoscientists better understand seal heterogeneity and quality in data-poor basins.