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岩溶对于目前的工程建设是一个很大的隐患。本文介绍了井间地震层析成像的原理及工作方法,简要地阐述了地震波的反演理论基础。并利用层析成像反演软件对其在工区里获得的原始数据进行反演处理,对得到不同测线的反演剖面图进行解释。通过这一工程实例的应用效果,说明井间地震CT技术在圈定岩溶勘察中具有较高的精度和可信度,为工程设计提供了可靠的依据。 相似文献
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井间电磁波CT技术是利用地层间介质的物性差异，不同性质的物质对电磁波的反射和吸收能力是不同的。井间电磁波CT技术在探测岩溶裂缝等方面有较好效果，本文利用井间电磁波CT技术，对昆明地铁四号线苏家塘站岩溶专项线路工程地下岩溶发育地段进行测试，通过对工区岩石电磁波吸收系数差异的研究，依据吸收系数特征，探测到地铁线路工程地下岩溶及裂缝发育，划分出4个层次的岩溶区，经与钻孔岩心资料对比，证实探测结果的正确性。且对工程设计和施工提供了必要的基础资料。 相似文献
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利用井间电磁波CT技术可以对地下岩溶、破碎带等问题进行精细探查。本文通过构建岩溶区域模型，利用数值模拟手段对岩溶区进行电磁波CT透视模拟，讨论电磁波在岩溶发育区的衰减及响应特征。结合杭州某地实施孔间电磁波透视成像，对岩溶发育区进行解释，并与钻孔实际揭露地质资料相对比，结果表明电磁波CT对探测岩溶发育区效果良好。 相似文献
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井间地震资料分辨率很高,但是缺乏成熟的解释方法,本文针对井间地震资料的特点,借鉴地面地震解释技术对井间地震资料开展了精细解释方法研究.首先在深度域资料特点分析的基础上,利用区域速度和层析成像速度将深度域井间地震资料转换到时间域进行研究,并通过粗化降频建立起井间地震资料与地面地震资料之间的相似性联系,得到对井间地震低频反射特征的认识,结合井旁道合成地震记录标定建立起井间地震资料的反射特征,准确的解释了井间地震的反射层位.采用地震瞬时属性分析和时频属性分析得到了对沉积环境的认识,进一步通过波阻抗反演更好的认识井间储层特征.在实际应用中综合多种方法进行解释,并结合测井资料对比落实了井间砂体展布特征,得到对井间储层的精细描述结果,解决了两口井之间储层分布范围、横向连通性及厚度变化等问题,取得了较好的应用效果. 相似文献
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城市地铁工程中经常遇到岩溶等不良地质现象,勘察阶段需要查明其发育的位置及规模。然而,地下岩溶分布的隐蔽性、城市环境的复杂性使得岩溶勘察具有相当大的难度。本文采用综合物探方法对南京某地铁工程的岩溶发育情况进行了探查,分析以等值反磁通瞬变电磁法、弹性波CT法为主的综合物探方法在岩溶探测中的应用效果。 相似文献
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针对井间地震数据成像技术的一些缺陷并根据井间地震数据的特点,利用井间上、下行反射波信息,提出了一种基于波动方程的井间地震反射波偏移成像技术,该技术既考虑了井间地震数据的运动学特征(时间信息),又考虑了动力学特征(振幅信息).以PC机集群为计算平台,Linux为操作系统,设计了井间地震炮域波动方程偏移成像并行计算流程,并且在64位联想机群上用井间模型数据和某油田的实际数据对该技术和计算流程进行了测试和试处理,试验结果表明成像方法和并行算法正确、实用且计算效率高. 相似文献
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为了研究松南地区陆相砂泥岩薄互层储层岩石物性横向变化、微构造等对油气聚集的影响和探索利用高分辨率井间地震技术直接指示油气分布的可能性,开展了井间地震及地面小三维地震、VSP、测井等立体地震观测．使用了自行研制的井中炸药震源和常规地震记录仪器．采用层析成像方法、反射资料叠前偏移成像方法等对采集到的资料进行研究,得到了不同分辨率的地下构造和岩石物性信息,展示出不同方法技术在分辨薄储层能力上的差异．高分辨率的井间地震成果较好地实现了井间地层对比,查清了两井间储层横向变化和油气分布情况．层析速度与构造信息等的综合应用解释了两井油气产能差异的原因,建立了油气地质模型．所得成果显示出井间地震技术在油气开发中的潜力． 相似文献
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Gary J. Barnes John M. Lumley Phill I. Houghton Richard J. Gleave 《Geophysical Prospecting》2011,59(1):176-187
Noise levels in marine and airborne full tensor gravity gradiometer surveys together with conventional land, marine and airborne gravity surveys are estimated and analysed in gridded form, resulting in relations that detail how these different survey systems can be compared analytically. After defining survey parameters including line spacing, speed and instrument bandwidth, the relations estimate the noise levels that result on either grids of gravity (gz) or gravity gradient (Gzz) as a function of the spatial filtering often applied during geological interpretation. Such comparisons are believed to be a useful preliminary guide for survey selection and planning. 相似文献
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1 全球地震活动概况
据中国地震台网测定,2012年全球共发生7级以上地震20次(表1),其中包括2次8级以上地震,即2012年4月11日苏门答腊北部附近海域8.6级、8.2级地震(图1).与2011年相比,全球地震频次和能量释放明显减少.2012年全球7级以上地震活动有以下特点:
1.1 全球8级地震继续活跃
2012年全球共发生7级以上地震20次,比1900年以来的平均水平(18次/年)略高,与2011年(26次)相比,地震频次减少(图2).虽然2012年4月11日苏门答腊北部附近海域发生8.6级、8.2级地震,但与2011年(3月11日发生日本9.0级地震)相比,全球地震能量释放减少较明显. 相似文献
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Stream networks used in studies of basin morphometry, network topology, flood hydrology, and sediment production should be defined as precisely as possible. Previous work has drawn attention to the way in which stream network definition varies on maps of different scales, on maps employing different conventions devised in relation to the dynamic network, and according to whether maps, remote sensing or field survey sources are used. Networks also vary in extent according to the date of survey and after considering the instructions to surveyors it is shown that such changes, over periods of 100 years reflect changes in network extent. For three areas of Britain, network change can be identified by comparison of maps of different dates, by comparison of these changes with the results of field survey, and by reference to dateable features such as inclosure boundaries. Changes of drainage networks since the nineteenth century are shown to be significant in extent and they have often occurred as a result of the replacement of flushes by clearly defined stream channels. This transformation has often occurred as a result of new or modified systems of stormwater drainage from roads, tracks or farms, and the planning of the future disposal of road drainage should be considered carefully in relation to such stream network changes. The changes of drainage networks identified from maps of different dates and editions can provide a useful data base for studies of network topology and may also be significant in relation to palaeohydrological investigations. 相似文献
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1 SURVEY OF GLOBAL SEISMICITY IN 2011A total of 26 strong earthquakes with MS ≥ 7. 0 occurred in 2011 throughout the worldaccording to the China Seismic Network ( Table 1 ) . The strongest earthquake was the Japanearthquake measuring MS9. 0 on March 11 ( Fig. 1) . The frequency was slightly lower and the 相似文献
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现代海底热液活动的调查研究方法 总被引：11，自引：0，他引：11
介绍了国外在现代海底热液活动调查研究中使用的方法和技术手段。现代海底热液活动是普遍发育于大洋中活动板块边界及板内火山活动中心的一种在岩圈和大洋之间进行能量和物质交换的过程。其突出的表象是高温的热液从海底流出，并由此造成热液活动区和上限覆水体的物理和化学异常。海底热测量、海底岩石取样、水体的CH4、^3He和Mn异常观测、硅氧异常观测、多波束测量、OBS观测、深潜调查等都是进行现代海底热液活动调查研究的重要手段。其中水体异常的观测是最为快捷有效的，而深潜器直接观测是现代海底热液活动研究必不可少的。 相似文献
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山西断裂带活动趋势与动态特征 总被引：12，自引：1，他引：12
利用沿山西断裂带布设的GPS监测网的 6期复测资料 (1996～ 2 0 0 1) ,分析了山西断裂带水平运动的趋势及动态活动特征。结果表明 :(1)现阶段趋势性活动表现为北段向西运动 ,南段向东运动 ,整体呈现逆时针的差异活动性质 ;但趋势性活动强度并不高 ,断裂带从南到北在垂直方向上的趋势性差异运动分量为 3mm a左右 ;该带的南北向伸展运动量也只有 1mm a ,而且主要发生在断裂带的北段。 (2 )趋势性运动所反映主压应变场的方位角为 72°。 (3)每年间的活动性质并不完全相同甚至相反 ,并偏离趋势性活动 ,由此所推算出的应变场参数不能反映基本应力场的物理特性。 (4)高频运动 (每年的 )不但存在而且复杂 ,强度是趋势运动的数倍。 (5 )无论是长趋势性活动还是每年的活动都看不出区内任何一条断裂两侧存在明显的差异性运动(包括走滑运动 )。趋势性运动结果不仅验证了华北地区西界受力“南强北弱”的基本特征 ,而且一直持续到华北腹地。断裂两侧无明显的差异活动可能说明板内各块体之间的差异活动是在一定的空间范围内通过渐变来完成的 ,并不是以某一条断裂或狭小条带为界的突变过渡来实现的。动态活动明显存在则可能表明 :(1)在基本应力场的大环境下存在着应力扰动行为。 (2 )由于介质的物性存在着差异 ,区域应力 相似文献
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An information-fusion method to identify pattern of spatial heterogeneity for improving the accuracy of estimation 总被引：1，自引：0，他引：1
Lianfa Li Jinfeng Wang Zhidong Cao Ershun Zhong 《Stochastic Environmental Research and Risk Assessment (SERRA)》2008,22(6):689-704
While spatial autocorrelation is used in spatial sampling survey to improve the precision of the feature’s estimate of a certain
population at area units, spatial heterogeneity as the stratification frame in survey also often have a considerable effect
upon the precision. Under the context of increasingly enriched spatiotemporal data, this paper suggests an information-fusion
method to identify pattern of spatial heterogeneity, which can be used as an informative stratification for improving the
estimation accuracy. Data mining is major analysis components in our method: multivariate statistics, association analysis,
decision tree and rough set are used in data filter, identification of contributing factors, and examination of relationship;
classification and clustering are used to identify pattern of spatial heterogeneity using the auxiliary variables relevant
to the goal and thus to stratify the samples. These methods are illustrated and examined in the case study of the cultivable
land survey in Shandong Province in China. Different from many stratification schemes which just uses the goal variable to
stratify which is too simplified, information from multiple sources can be fused to identify pattern of spatial heterogeneity,
thus stratifying samples at geographical units as an informative polygon map, and thereby to increase the precision of estimates
in sampling survey, as demonstrated in our case research. 相似文献
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Three‐dimensional seismic survey design should provide an acquisition geometry that enables imaging and amplitude‐versus‐offset applications of target reflectors with sufficient data quality under given economical and operational constraints. However, in land or shallow‐water environments, surface waves are often dominant in the seismic data. The effectiveness of surface‐wave separation or attenuation significantly affects the quality of the final result. Therefore, the need for surface‐wave attenuation imposes additional constraints on the acquisition geometry. Recently, we have proposed a method for surface‐wave attenuation that can better deal with aliased seismic data than classic methods such as slowness/velocity‐based filtering. Here, we investigate how surface‐wave attenuation affects the selection of survey parameters and the resulting data quality. To quantify the latter, we introduce a measure that represents the estimated signal‐to‐noise ratio between the desired subsurface signal and the surface waves that are deemed to be noise. In a case study, we applied surface‐wave attenuation and signal‐to‐noise ratio estimation to several data sets with different survey parameters. The spatial sampling intervals of the basic subset are the survey parameters that affect the performance of surface‐wave attenuation methods the most. Finer spatial sampling will reduce aliasing and make surface‐wave attenuation easier, resulting in better data quality until no further improvement is obtained. We observed this behaviour as a main trend that levels off at increasingly denser sampling. With our method, this trend curve lies at a considerably higher signal‐to‐noise ratio than with a classic filtering method. This means that we can obtain a much better data quality for given survey effort or the same data quality as with a conventional method at a lower cost. 相似文献
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近日,在美国最新国家研究计划“大数据计划”框架下,包括美国国家科学基金会、美国地质调查局和美国国家航空航天局在内的美国政府主要机构同时推出新的研究项目,并对现有研究部署做出相应调整,此举将带动包括地球科学在内的各领域研究的新发展;与此同时,英国地质调查局也公布了其地球科学新领域的最新研究进展.通过解读这些最新的研究计划,可以揭示出国际地球科学研究的新动向. 相似文献