共查询到19条相似文献，搜索用时 125 毫秒
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在基于褶积模型的子波提取中,大多假设地震子波为最小相位性质。虽然在地震资料处理中进行了相位转换和Q补偿处理,但从实际地震记录中提取的地震子波,大多也表现为混合相位性质。提取吸收系数大多采用地震记录谱模拟方法,即用地震记录振幅谱平滑代替子波振幅谱,这样就会存在一个误差项,给以常规方法提取的吸收系数地震剖面属性解释带来更多的不确定性。针对以上问题,在地震叠偏剖面上,动态计算地震子波的振幅谱和相位谱,可得到任意相位性质的地震子波,采用谱比法并应用相位项提取较准确的吸收系数。利用动态子波提取的吸收系数剖面,精细显示出储层中含油气和未含油气区域的明显差异,结合嘉陵江组一段动态吸收系数平面图分析,为工区储层的精细解释提供了一种精确的方法。 相似文献
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全波形反演(full waveform inversion, FWI)是目前精度最高的一种速度反演工具,通过迭代反演得到高精度的地下构造,为叠前成像技术提供更准确的速度场,满足目前勘探开发日益复杂的需求。但FWI需要估计精确的震源子波,而从野外采集的地震数据提取子波是非常困难的,此外,反演过程中,模型参数与观测数据存在强的非线性关系,容易产生周波跳跃现象。针对中低波数反演过程中存在周波跳跃现象与地震子波难提取的问题,本文构建了一种基于组合震源的多尺度波形反演方法。首先对子波和地震数据进行时移组合叠加,再进行互相关梯度求取,只需要一次逆时偏移的计算量,就可以完成梯度的求取,实现多尺度反演的目标。通过模型试算,基于组合震源的FWI方法,可以达到多尺度反演的目的,使得反演结果更稳定;与不依赖子波的方法相结合,反演结果相对准确。 相似文献
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《中国煤炭地质》2015,(6)
确定地震反演子波以及处理其与各井最优标定子波之间的差异是地震反演与解释所面临的问题之一。以陕北侏罗纪煤田榆横矿区某勘探区为例,对其地震资料采用不同的子波进行标定与反演实验,研究地震子波变化引起的波阻抗数值和结构在纵横向上的变化规律,并讨论其对地质解释的影响。研究表明,在基于模型的反演中,标定和反演所用的地震子波对最终得到的波阻抗具有明显的影响,具体表现在波阻抗幅值、时间轴偏移、纵向变化细节以及横向连续性等。在该区选取子波的研究中还发现,子波变化产生的波阻抗差异逾700(m/s)*(g/cm3),这将导致在密度为2.6 g/cm3的地层中速度误差达300 m/s,其结果必会影响岩性解释的准确性。 相似文献
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《物探化探计算技术》2017,(2)
在地震反演中,地震信号可以认为反射系数与地震子波的褶积,在此过程地震子波振幅保持不变。这里提出一种修正的褶积模型,将透射损失融入褶积过程中,表现为子波振幅的衰减,对于砂泥岩互层介质,修正褶积模型更加真实地刻画地震信号形成过程。基于修正褶积模型建立新的反演目标函数,反演得到的反射系数消除了透射损失的影响。与基于常规褶积反演得到的反射系数相比较,此方法保证了更多有效信息的体现。实际资料应用表明,基于修正褶积模型的地震反演方法提高了反演结果的合理性。 相似文献
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高分辨率地震反演面临着:①地震反演是一个不适定问题,存在多解性;②采集和处理流程产生噪声和畸变降低反演算法的稳定性,针对这两个问题,提出一种基于L_1-L_1范数稀疏表示的地震反射系数反演方法。该方法利用L_1范数正则化项降低反演多解性和L_1范数拟合项增加噪声鲁棒性。通过井震联合提取子波构建过完备楔形子波字典,然后用L_1-L_1范数稀疏表示对地震信号进行稀疏分解,实现高分辨率反射系数反演。楔形模型和实际地震资料试算结果表明,该反演算法稳定,具有良好的噪声鲁棒性,通过测井资料标定检验,其反演结果准确可信。 相似文献
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二维连续复小波变换识别重力场源 总被引：3，自引：2，他引：3
利用旋转反投影法由位场一维连续母小波构造出二维连续母小波,同时也给出了位场中适应性非常强的矢量分析母小波和张量分析母小波。在理论模型上(直方棱柱体和球体)进行了二维连续小波变换,估计了场源的尺度指数,通过尺度指数与欧拉结构指数关系式得到场源的欧拉结构指数,由此可以识别出重力场源的类型,成功地实现了重力场源的快速反演。此法实用于重磁资料快速自动化处理、反演与解释。 相似文献
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《Physics and Chemistry of the Earth, Part A: Solid Earth and Geodesy》1999,24(3):261-268
Visualisation of seismic and tomographic results is a crucial point to properly understand the models provided by seismic methods. We consider several geostatistical methods (inverse distance weighting, point kriging and mathematical wavelets) to map surface wave tomography in a sparsely sampled study area, and to compare their accuracy and efficiency with proper raypath methodologies (inversion and projection onto convex sets). A large set of synthetic data is used to estimate seismic velocities before application to real data. The contour maps of prediction errors indicate that spatial prediction and inversion perform similarly. 相似文献
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"先成型"致密砂岩气的勘探重点是寻找相对高孔渗砂岩,基于该观点,以鄂尔多斯盆地东缘上古生界为研究对象,以"相控储层"为思路,结合构造、沉积等研究成果,开展测井约束反演工作,以此寻找相对高孔渗优质储层。研究区有利储层较为成功的预测表明,依据地质、测井资料,采用拟声波重构技术可有效提高测井曲线岩性识别能力,并为砂岩识别提供波阻抗门槛;利用自动迭代子波扫描求取每口井的最佳子波,实行多个子波同时参与反演,可获得初始模型与井旁地震数据的最佳匹配。另外在构建地质模型时,针对不同储层的沉积特点,选取了不同的插值方式进行分段反演,有效划分出不同层段中有利区带及最佳目的层段。 相似文献
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Wavelet-based methods have been widely used for compression of remotely sensed images and data. Recently, second generation of wavelets which is based on a method called lifting has proven to be more effective than traditional wavelets as it provides lossless compression, lowers the memory usage, and is computationally faster. This study explores the literature related to applying second-generation wavelets for the compression of remote sensing data. Nevertheless, in order to compare the results of two wavelet types, some applications of traditional wavelets are also presented. 相似文献
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综合研究区地质、地震、测井、录井等各类信息,从测井约束稀疏脉冲波阻抗的反演技术的基本原理出发,探讨反演过程中测井资料的标准化处理、地震子波的提取、时深关系的转化,以及初始波阻抗模型的建立等主要的技术环节。综合分析了研究区双阳组二段重点圈闭区块砂体的发育和分布情况,并探讨在同一构造圈闭上不同井位失利的原因,为精细的油气储层研究提供了可靠的信息。 相似文献
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A review of applying second-generation wavelets for noise removal from remote sensing data 总被引：1，自引：0，他引：1
Ladan Ebadi Helmi Z. M. Shafri Shattri B. Mansor Ravshan Ashurov 《Environmental Earth Sciences》2013,70(6):2679-2690
The processing of remotely sensed data includes compression, noise reduction, classification, feature extraction, change detection and any improvement associated with the problems at hand. In the literature, wavelet methods have been widely used for analysing remote sensing images and signals. The second-generation of wavelets, which is designed based on a method called the lifting scheme, is almost a new version of wavelets, and its application in the remote sensing field is fresh. Although first-generation wavelets have been proven to offer effective techniques for processing remotely sensed data, second-generation wavelets are more efficient in some respects, as will be discussed later. The aim of this review paper is to examine all existing studies in the literature related to applying second-generation wavelets for denoising remote sensing data. However, to make a better understanding of the application of wavelet-based denoising methods for remote sensing data, some studies that apply first-generation wavelets are also presented. In the part of hyperspectral data, there is a focus on noise removal from vegetation spectrum. 相似文献
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Patterns of crystallographic preferred orientation are referred to as texture. The specific subject of texture analysis is
the experimental determination and interpretation of the statistical distribution of orientations of crystals within a specimen
of polycrystalline material, which could be metals or rocks. The objective is to relate an observed pattern of preferred orientation
to its generating processes and vice versa. In geosciences, texture of minerals in rocks is used to infer constraints on their
tectono-metamorphic history. Since most physical properties of crystals, such as elastic moduli, the coefficients of thermal
expansion, or chemical resistance to etching depends on crystal symmetry and orientation, the presence of texture imparts
directional properties to the polycrystalline material.
A major issue of mathematical texture analysis is the resolution of the inverse problem to determine a reasonable orientation
density function on SO(3) from measured pole intensities on
, which relates to the inverse of the totally geodesic Radon transform. This communication introduces a wavelet approach into
mathematical texture analysis. Wavelets on the two-dimensional sphere
and on the rotational group SO(3) are discussed, and an algorithms for a wavelet decomposition on both domains following the
ideas of Ta-Hsin Li is given. The relationship of these wavelets on both domains with respect to the totally geodesic Radon
transform is investigated. In particular, it is shown that the Radon transform of these wavelets on SO(3) are again wavelets
on
. A novel algorithm for the inversion of experimental pole intensities to an orientation density function based on this relationship
is developed. 相似文献