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对于孔径过小,采样不充分的地震数据,抛物线拉冬变换的多次波压制效果不理想,且存在空间假频问题。综合Sacchi、Mauricio、Todd Mojesky等对抛物线拉冬变换压制多次波的分析,阐明了高分辨率抛物线拉冬变换原理。通过理论模型试验和实际地震数据的分析证明,高分辨率抛物线拉冬变换可以突破离散采样和有限孔径的限制,实现对地震数据中的多次波及空间假频的快速、有效压制。 相似文献
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《物探与化探》2015,(6)
叠前CMP道集中,走时为双曲线的地震反射同相轴经过部分动校正(NMO)之后变为近似抛物线,当道集中缺失某些地震道时,可利用抛物线Radon变换通过迭代计算进行地震道的重建和恢复。笔者基于抛物线Radon变换的基本原理,利用加权抛物线Radon变换的计算方法,进行叠前地震道的恢复和重建,并且在数据域对其加权系数进行改进和优化,模型数据和实际资料的试算结果表明,改进后的计算方法即使在较强的随机噪声下依然可以稳建同相轴,且避免了常规方法在重建过程中产生虚假同相轴的缺点,与原始的加权抛物线Radon变换的计算方法相比,新方法具有压制随机噪声的优点,即具有较好的抗噪性,计算精度也有所提高,且算法稳健、高效,具有良好的应用前景。 相似文献
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f-x域随机噪声压制方法面临着2个问题:叠前共炮点道集或CMP道集反射波同相轴为双曲线型,去噪同时会损害有效波;地震信号为复杂的非平稳信号,要求去噪方法具有自适应性。基于f-x EEMD的共偏移距道集随机噪声压制方法利用了共偏移距道集反射波同相轴为水平满足f-x域去噪假设条件和EEMD算法对非平稳信号的良好适应性,对f-x域每一个等频率切片做EEMD分解,并去除以高频随机噪声为主的第一个IMF分量,最后将f-x域数据反变换回t-x域,实现噪声分离。正演模拟和实际地震数据试算结果表明:该方法在压制随机噪声的同时,能够保持有效信号。 相似文献
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《物探化探计算技术》2015,(6)
多次波是海洋资料处理中最主要的噪音,目前有多种多次波压制方法,但每一方法均有其优势和局限性,任意一种单一的方法均难有效地消除各种多次波,常采用SRME、拉冬、分频去绕射多次波组合的方法进行多次波的去除。在某些工区,即使采用上述组合方法仍然有能量强、频带宽的残余多次波,用常规的方法难以对其进行去除,对这类残余的多次波,这里提出运用f-x域预测反褶积的方法进行去除。该方法主要在共偏移距道集上进行处理,是基于f-x域信号的可预测性进行多次波的衰减,首先追踪出待消除多次波对应有效波的层位,再以此层位信号为依据,在f-x域内进行预测反褶积,压制多次波后,再将其共偏移距道集进行成像。通过理论数据模拟与实际资料验证得出:该方法对压制资料残余的强能量多次波,具有很好的压制效果。 相似文献
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基于稀疏离散τ-p变换的叠后地震道外推 总被引:2,自引:0,他引:2
这里研究的是一种基于稀疏离散τ-p变换的地震道缺失重建方法。该方法根据叠后零偏移距剖面,在局部时窗内可以看作是一系列线性同相轴的组合,使用稀疏离散τ-p和预条件双共轭梯度算法进行地震道外推,使空间方向的缺失道得到恢复。τ-p变换由于信息不足,有限的孔径和离散等因素,导致在τ-p域的结果存在假象、不准确,而在τ-p域进行稀疏对于重建缺失的信息是非常有用和必要的。同时,还可使用迭代的预条件双共轭梯度算法进行计算。 相似文献
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波动方程角度域共成像道集 总被引:1,自引:0,他引:1
针对基于波场深度递推的波动方程叠前深度偏移成像方法难以准确地给出如Kirchhoff积分叠前深度偏移成像方法的偏移距域共成像道集的不足,在分析研究现有的各种波动方程偏移成像共成像道集方法的基础上,利用波场外推的单平方根算子和波场的窗口Fourier框架展开与重构方法,提出一种局部角度域共成像道集方法——成像点处反射角共成像道集方法.把这种角度域共成像道集方法应用于国际标准的Marmousi模型数据和一条实际二维地震数据都取得了理想的结果.提出的波动方程反射角度域共成像道集方法可为进一步的叠前偏移数据振幅随角度变化分析和偏移速度分析工作提供基础. 相似文献
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通过对地震观测系统设计及CRP面元的分析,获得了不同观测系统及覆盖次数下CRP面元内偏移距与方位角的分布情况.研究表明:对于满36次覆盖面元内的偏移距与方位角来说,8线10炮观测系统较8线8炮分布更为均匀,偏移距信息与宽方位角信息缺失较少,有利于进行岩性勘探.对于8线10炮同一观测系统,24次覆盖较36、48次覆盖其方位角分布均匀,但缺失大角度道集;而48次覆盖偏移距信息更为均匀丰富,却存在小角度道集缺失的情况.盲目的增加覆盖次数将会降低地震资料的分辨率,影响地震资料的构造解释. 相似文献
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Emily Keeble David I. Whiteside Michael J. Benton 《Proceedings of the Geologists' Association. Geologists' Association》2018,129(2):99-119
Pant-y-ffynnon Quarry in South Wales yielded a rich cache of fossils in the early 1950s, including articulated specimens of new species (the small sauropodomorph dinosaur Pantydraco caducus and the crocodylomorph Terrestrisuchus gracilis), but no substantial study of the wider fauna of the Pant-y-ffynnon fissure systems has been published. Here, our overview of existing specimens, a few described but mostly undescribed, as well as freshly processed material, provides a comprehensive picture of the Pant-y-ffynnon palaeo-island of the Late Triassic. This was an island with a relatively impoverished fauna dominated by small clevosaurs (rhynchocephalians), including a new species, Clevosaurus cambrica, described here from a partially articulated specimen and isolated bones. The new species has a dental morphology that is intermediate between the Late Triassic Clevosaurus hudsoni, from Cromhall Quarry to the east, and the younger C. convallis from Pant Quarry to the west, suggesting adaptive radiation of clevosaurs in the palaeo-archipelago. The larger reptiles on the palaeo-island do not exceed 1.5?m in length, including a small carnivorous crocodylomorph, Terrestrisuchus, and a possible example of insular dwarfism in the basal dinosaur Pantydraco. 相似文献
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Gilles Serge Odin 《Comptes Rendus Geoscience》2002,334(6):409-414
Lithostratigraphy, physicochemical stratigraphy, biostratigraphy, and geochronology of the 77–70 Ma old series bracketing the Campanian–Maastrichtian boundary have been investigated by 70 experts. For the first time, direct relationships between macro- and microfossils have been established, as well as direct and indirect relationships between chemo-physical and biostratigraphical tools. A combination of criteria for selecting the boundary level, duration estimates, uncertainties on durations and on the location of biohorizons have been considered; new chronostratigraphic units are proposed. The geological site at Tercis is accepted by the Commission on Stratigraphy as the international reference for the stratigraphy of the studied interval. To cite this article: G.S. Odin, C. R. Geoscience 334 (2002) 409–414. 相似文献
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The effect of water on accessory phase solubility in subaluminous and peralkaline granitic melts 总被引:4,自引:0,他引:4
The solubilities of columbite, tantalite, wolframite, rutile, zircon and hafnon were determined as a function of the water contents in peralkaline and subaluminous granite melts. All experiments were conducted at 1035 °C and 2 kbar and the water contents of the melts ranged from nominally dry to approximately 6 wt.% H2O. Accessory phase solubilities are not affected by the water content of the peralkaline melt. By contrast, solubilities are affected by the water content of the subaluminous melt, where the solubilities of all the accessory phases examined increase with the water content of the melt, up to 2 wt.% H2O. At higher water contents, solubilities are nearly constant. It can be concluded that water is not an important control of accessory phase solubility, although the water content will affect diffusivities of components in the melt, thus whether or not accessory phases will be present as restite material. The solubility behaviour in the subaluminous and peralkaline melts supports previous spectroscopic studies, which have observed differences in the coordination of high field strength elements in dry vs. wet subaluminous granitic glasses, but not for peralkaline granitic glasses. Lastly, the fact that wolframite solubility increases with increasing water content in the subaluminous melt suggests that tungsten dissolved as a hexavalent species. 相似文献
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Emmanuel Skourtsos Daniel Vachard Alexandra Zambetakis-Lekkas Rossana Martini Louisette Zaninetti 《Comptes Rendus Geoscience》2002,334(12):925-931
Some olistolites reworked in a Tertiary flysch of Mount Parnon (Peloponnesus, Greece) exhibit a Late Permian assemblage, dominated by Paradunbarula (Shindella) shindensis, Hemigordiopsis cf. luquensis and Colaniella aff. minima. This association corresponds to the Late Wuchiapingian (=Late Dzhulfian), a substage whose algae and foraminifera are generally little known. Contemporaneous limestones crop out in the middle part of the Episkopi Formation in Hydra, but they are rather commonly reworked in Mesozoic and Cainozoic sequences. The palaeobiogeographical affinities shared by the foraminiferal markers of Greece, southeastern Pamir, and southern China, are very strong (up to the specific level), and are congruent with the Pangea B reconstructions. To cite this article: E. Skourtsos et al., C. R. Geoscience 334 (2002) 925–931. 相似文献
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正20141596 Liu Yunhuan(School of Earth Sciences and Resources,Chang’an University,Xi’an 710054,China);Shao Tiequan Early Cambrian Quadrapyrgites Fossils of Xixiang Boita in Southern Shaanxi Province(Journal of Earth Sciences and Environment,ISSN1672-6561,CN61-1423/P,35(3),2013,p.39-43,3 illus.,20 refs.) 相似文献
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正20141719 Chen Zhijun(State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences,Wuhan 430074,China);Chen Jianguo Automated Batch Mapping Solution for Serial Maps:A Case Study of Exploration Geochemistry Maps(Journal of Geology,ISSN1674-3636,CN32-1796/P,37(3),2013,p.456-464,2 illus.,2 tables,10 refs.) 相似文献
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正20140962 Chen Fenning(Xi’an Institute of Geology and Mineral Resources,Xi’an710054,China);Chen Ruiming Late Miocene-Early Pleistocene Ostracoda Fauna of Gyirong Basin,Southern Tibet(Acta Geologica Sinica,ISSN0001-5717,CN11-1951/P,87(6),2013,p.872-886,6illus.,56refs.) 相似文献
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正1.IGNEOUS PETROLOGY20142008Cai Jinhui(Wuhan Center,China Geological Survey,Wuhan 430205,China);Liu Wei Zircon U-Pb Geochronology and Mineralization Significance of Granodiorites from Fuzichong Pb-Zn Deposit,Guangxi,South China(Geology and Mineral Resources of South China,ISSN1007-3701,CN42-1417/P,29(4),2013,p.271-281,7illus., 相似文献
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正20141205Cheng Weiming(State Key Laboratory of Resources and Environmental Information System,Institute of Geographic Sciences and Natural Resources Research,CAS,Beijing 100101,China);Xia Yao Regional Hazard Assessment of Disaster Environment for Debris Flows:Taking Jundu Mountain,Beijing as an 相似文献
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正20141266Fan Chaoyan(Guangdong Provincial Key Laboratory of Mineral Resources and Geological Processes,Guangzhou 510275,China);Wang Zhenghai On Error Analysis and Correction Method of Measured Strata Section with Wire Projection Method(Journal of 相似文献