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1.
《物探化探计算技术》2015,(3)
基于地质统计先验信息的随机地震反演方法是一种基于蒙特卡洛的非线性反演方法。在贝叶斯理论框架下,通过序贯高斯模拟方法(sequential Gaussian simulation,SGS)和逐渐变形算法(Gradual Deformation Method,GDM)得到基于地质统计学的先验信息,然后构建似然函数,最终利用Metropolis算法实现后验概率密度的抽样,得到反演问题的解。与确定性反演结果相比,该方法能够有效地融合测井资料中的高频信息,提高反演结果的分辨率。数值模拟试验表明:本方法的反演结果与理论模型吻合较好,具有较高的分辨率;序贯高斯模拟采用一种新的逐点模拟方式,并结合GDM,有效提高了随机反演的计算效率。 相似文献
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基于分形先验信息的非线性反演方法能综合利用测井数据和地震信息,在贝叶斯框架下,通过分形高斯噪音算法得到基于分形理论的先验信息,然后根据地震资料构建似然函数,最终利用基于快速模拟退火算法(Very Fast Simulated Annealing,VFSA)改进的粒子群优化(Particle Swarm Optimization,PSO)算法(VFSA-PSO)实现后验概率密度的抽样。与确定性反演结果相比,该方法能够有效地融合测井资料中的高频信息,提高反演结果的分辨率,并且目标函数的建立融合了确定性反演中的低频约束,从而得到宽频带的反演结果。数值模拟试验表明:基于分形先验的非线性反演结果与理论模型吻合较好,实际资料的应用效果也证明了该反演方法的有效性。 相似文献
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地震波阻抗反演可以直接提供地下介质的弹性信息，为后续的煤层识别，水通道预测以及陷落柱识别等提供可靠的资料。在面对复杂地质条件时，现有的波阻抗反演方法精度较低，不能满足实际勘探的需求。反射率法通过求解弹性波动方程获得弹性参数信息，能够模拟全波场响应以及地震波的各种传播效应，能更精确地考虑透射损失、多次波等引起的地震波振幅和相位变化，精度较高，且计算效率高于其他波动方程求解方法。因此，基于贝叶斯框架，建立了反射率法的反演目标函数并通过引入柯西分布作为先验分布提高反演结果的分辨率，形成了一种基于贝叶斯的反射率法波阻抗反演方法。将该方法应用于布尔台煤矿地震数据中，获得的波阻抗反演结果与测井资料匹配度较好，相比于常规方法分辨率更高，精度高，能够有效识别薄煤层和深部煤层分布，有效验证了新方法的可行性和有效性。该方法能为利用地震反演技术识别煤层及陷落柱等小构造，预测顶底板水分布提供有力的资料。 相似文献
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模型评价（模型选择）是地下水数值模拟不确定分析的重要研究内容,模型边缘似然值是进行模型评价的重要依据。嵌套抽样算法是一种高效的高维积分计算方法,能有效计算复杂模型的边缘似然值。本次研究提出了一种基于Adaptive Metropolis的嵌套抽样算法,通过对两个（线性、非线性）解析函数及一组不同结构的地下水模型边缘似然值的计算,并与大样本条件下算术平均方法的计算结果相对比,验证了该方法对于计算模型边缘似然值的有效性。 相似文献
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《物探化探计算技术》2016,(3)
弹性阻抗反演是结合声阻抗反演与AVO反演的叠前地震反演技术,能够克服叠后波阻抗反演的缺陷,反映振幅随偏移距变化的信息,已经广泛应用于地震岩性识别和流体特征的获取。常规的线性迭代弹性阻抗反演方法存在依赖初始模型、容易陷入局部极值等缺陷。针对这一问题,提出了一种基于改进粒子群算法的弹性阻抗非线性反演方法,并利用该算法对胜利油田某工区地震资料进行了弹性阻抗反演,获得了多个弹性参数剖面,与实际钻井结果相符,该方法为复杂油气藏的勘探开发提供了一种有效可行的途径。 相似文献
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重力梯度张量的定义是对重力位求二阶导数,相比于传统的布格重力异常,它在反映地下密度异常分布上有着更高的灵敏度,且能够进一步准确直接地反映目标体的边界.但对单个张量分量作反演时,可能会丢失一部份有用的信息,从而造成反演结果的误差.而全张量反演是将重力的五个梯度张量联合起来进行反演,这样做可以综合更丰富的场源信息.相比于传统做法中的布格重力异常反演和单重力张量分量反演,得到的反演结果不仅有了更高的分辨率,在识别目标体特征上也有更好的效果.粒子群算法是一种基于群体智能的优化迭代算法,这里利用粒子群算法对重力张量单分量、布格重力异常和全张量分别进行反演,并对结果进行简要分析. 相似文献
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反演问题一直是地球物理的重点研究问题之一。本文以长导线源半航空瞬变电磁为例,对时间域半航空数据进行一维反演研究。将自适应正则化(ARIA)反演方法和阻尼最小二乘(LM)反演方法相结合,提出一种改进的反演方法:自适应正则化-阻尼最小二乘(ARIA-LM)反演算法。本文选用三层理论模型对比阻尼最小二乘算法、自适应正则化反演算法与本文方法,并使用四层理论地层模型来验证算法的有效性和可靠性。结果表明:该算法在一定程度上对高阻分辨率增强,能有效提高反演的精度及稳定性。 相似文献
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《物探化探计算技术》2015,(4)
非线性反演方法在储层预测中得到了广泛地应用,但其通常只采用叠后波阻抗反演结果和叠后属性进行预测,进而忽略了叠前道集中包含的岩性信息。这里提出了一种基于叠前反演的储层预测方法,可以有效地利用叠前信息进行储层预测。首先对叠前道集进行针对性处理,使其满足叠前反演的要求,其次改进横波估算方法获得高精度的横波数据,并针对叠前数据进行子波提取,然后通过叠前反演获得纵波、横波阻抗和密度信息,最后结合叠前属性,采用概率神经网络方法(PNN)来反演储层孔隙度参数,该方法克服了叠后波阻抗反演进行储层预测造成的多解性问题,并提高了储层识别的精度,预测结果与测井一致,证明该方法正确有效。 相似文献
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提出一种基于谱反演方法的叠后地震数据纵波阻抗反演算法,用于提高地震反演精度。谱反演在地震高分辨率和反射系数反演中应用广泛,其基于反射系数的奇偶分解,能降低薄层之间的调谐效应,使反演数据体的分辨率得以提高,而由反射系数计算纵波阻抗的过程不适定,分步进行纵波阻抗反演会引入较大的累积误差。本研究提出基于谱反演方法的叠后纵波阻抗反演算法,引入TV正则化约束目标方程,通过迭代求解,可直接得到相对阻抗,然后同预先建立的低频模型进行频率域融合得到绝对阻抗。模型和实际数据说明,相比基于稀疏脉冲反褶积的阻抗反演,本文提出的方法反演分辨率较高,更有利于后续储层预测等研究的开展。 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