共查询到18条相似文献，搜索用时 140 毫秒
1.
《地球物理学进展》2015,(4)
共反射点道集中的噪声与剩余时差影响着偏移剖面的质量和叠前反演的精度.本文采用二次多项式拟合地震数据对地层倾向进行估计,并基于结构中值滤波方法对共反射点道集进行优化处理.在计算时窗内,对道集中每一个样点的二次多项式拟合系数进行精确扫描以确定样点所在同相轴方向并在同相轴方向进行中值滤波即结构中值滤波,滤波后道集信噪比得到提高同时保护了地层边缘特征.由于相关性在叠加剖面中要优于存在剩余时差的道集间,因此本文在叠加剖面上通过建立模型道来进行剩余时差校正即通过计算滑动时窗内待校正地震道和模型地震道间的互相关值,以最优化原则逐道估计剩余校正量,得到每个共反射点道集的剩余校正量模型,然后对剩余校正量模型在空间上做平滑处理,最后对共反射点道集进行时差校正.理论模型数据和实际数据的处理结果表明,该方法能够很好地解决道集中的信噪比和剩余时差问题,提高了共反射点道集和叠加剖面的整体质量. 相似文献
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静校正问题是地震勘探的关键问题，直接影响地震勘探精度和准确性.实际地震采集过程中，当在相同接收点位置上不同时间内插拔布设了不同的检波器时，对于目前基于地表一致性理论假设的基准面静校正和剩余静校正，以及非地表一致性剩余静校正都不具备适用条件.为解决这一问题，本文提出了基于共姿态道集的静校正方法，将相同接收点位置上不同时间布设的检波点所接收的地震数据抽成不同的共姿态道集，在共姿态道集内实施地表一致性静校正；当某接收点位置上具有若干个共姿态道集时，该接收点位置上可能会存在多个检波点静校量；炮点静校问题仍然采用地表一致性静校正方法解决.该方法解决了同一接收点位置上不同共姿态道集之间的非地表一致性静校正问题，同时也解决了全区的检波点和炮点的地表一致性静校正问题，在实际数据应用效果明显. 相似文献
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《地球物理学进展》2015,(3)
针对复杂探区因模型道品质差导致反射波剩余静校正效果不好的难题,本文提出了一种基于样条曲线拟合的二维初至波剩余静校正方法.该方法相对直线拟合法,可以用的初至信息更多,统计的短波长静校正量更为准确;相对折线拟合法,它不用拾取折射拐点,操作方便快捷,更具有可操作性.它采用三次样条函数将应用了长波长静校正量的初至拟合成一条光滑曲线,根据地表一致性原则将延迟时分解为炮点、检波点短波长静校正量.实际资料应用结果表明,基于样条曲线拟合的单炮初至变得光滑,叠加剖面同相轴连续性得到增强,可为反射波剩余静校正提供较好品质的模型道,对低信噪比资料剩余静校正问题的解决具有实际意义. 相似文献
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在地表地形复杂的情况下，静校正不易做好，这是制约山地资料处理质量的一个很重要的因素.复杂地表共反射面元（CRS）叠加不需对叠前数据做静校正，而且在得到叠加剖面后可以利用叠加得到的波场参数剖面实现基准面重建.地震数据的试算表明，复杂地表CRS叠加得出的剖面与常规处理剖面相比有着较高的信噪比和同相轴连续性.与水平地表CRS叠加不同的是，在复杂地表CRS叠加的时距公式中，波场三参数耦合，难以通过简化CRS道集的方法将它们全部分离并逐个优化.引入模拟退火算法后，有效地解决了这一组合优化的难题. 相似文献
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P-SV转换波处理与传统的P-P波处理有很大的不同,如S波静校正、CCP叠加、P-SV速度分析和偏移等,其中最大的难题就是S波静校正问题.S波速度基本不受潜水面的影响,与纵波静校正没有直接相关性,有时横波静校正量能达到纵波静校正量的十倍,用纵波静校正量乘以比例系数来解决横波静校正问题将导致较大误差.同一接收点X和Z分量存在一定的初至时差,该时差代表了P波和S波在低降速带的走时差,可以利用该时差和近地表纵横波速度比信息去除低降速带对横波的影响,得到准确的静校正量.本文利用多分量初至时差推导了较为精确的横波静校正公式,再结合共检波点叠加求取剩余静校正量的方法,形成了完整的转换波静校正配套方法.利用该方法对苏里格气田二维及三维多波地震资料进行了实际处理,数据处理结果证明了该方法的有效性,该方法尤其适用于其他方法难以奏效的风化层较厚地区的横波静校正量求解,该方法也同时考虑了长波长横波静校正问题. 相似文献
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针对复杂地表地质条件下地震资料覆盖次数不均、部分数据缺失而导致的地震资料品质下降、陡倾角地区成像质量变差等问题,文中采用了叠前三维共反射面叠加技术.共反射面叠加是一种与宏观速度无关且考虑了反射点曲率的地震成像方法.它利用共反射点道集一个邻域内(菲涅尔带)道之间的相关性,并将相干区域内道集的能量相加来增强地震反射信号和绕射波能量,并借助于相邻CMP道集数据形成CRS超道集,使得面元内的覆盖次数更加均匀;同时利用超道集的高覆盖次数来压制噪声,最终得到高信噪比道集数据.实际地震资料处理表明,该方法可大幅度地提高地震资料信噪比和分辨率,增强地震同相轴的连续性,此外还可为叠前偏移成像处理、AVO属性分析、叠前地震反演等提供高质量的输入数据. 相似文献
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《地球物理学进展》2015,(4)
水平叠加技术是提高地震资料的信噪比和分辨率的方法之一.只有当CMP道集同相轴校齐,消除各种时差,才能实现CMP道集中各道真正的同相位叠加,否则地震资料的高频信息会缺失,降低信噪比和分辨率.本文给出一种应用相位替换的处理方法消除CMP道集中的剩余时差,利用消除剩余时差后的CMP道集进行叠加.这种方法的理论基础是地震信号的到达时完全包含在信号的相位谱中,通过改变相位谱可以达到改变信号到达时的目的.综合理论模型和实际资料的数据处理,详细探讨了该方法对提高信噪比和分辨率的效果,结果表明,通过选取合适的参考道,该方法可有效地提高地震资料的信噪比和分辨率且理论上可以消除任何时差. 相似文献
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We apply interferometric theory to solve a three‐dimensional seismic residual statics problem to improve reflection imaging. The approach calculates the static solutions without picking the first arrivals from the shot or receiver gathers. The static correction accuracy can be significantly improved by utilising stacked virtual refraction gathers in the calculations. Shots and receivers may be placed at any position in a three‐dimensional seismic land survey. Therefore, it is difficult to determine stationary shots and receivers to form the virtual refraction traces that have identical arrival times, as in a two‐dimensional scenario. To overcome this problem, we use a three‐dimensional super‐virtual interferometry method for residual static calculations. The virtual refraction for a stationary shot/receiver pair is obtained via an integral along the receiver/shot lines, which does not require knowledge of the stationary locations. We pick the maximum energy times on the interferometric stacks and solve a set of linear equations to derive reliable residual static solutions. We further apply the approach to both synthetic and real data. 相似文献
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川东北复杂山地由于地表高程变化大、风化层厚度不均匀、低降速带速度横向变化大、高速层底界不稳定等因素，得到的地震资料具有严重的静校正问题，因此，如何解决山地静校正问题是后续地震资料处理的关键之一，本文首先分析高程静校正、折射静校正、层析静校正的基本原理和适用条件，结合实际复杂山地三维地震资料的特点，进行试验对比，提出了进行山地静校正的基本思路，即：首先进行高程静校正，这样可以利用高程静校正更容易拾取初至时间，然后利用折射静校正结合微测井等资料建立近地表速度-深度模型，以此速度-深度模型作为层析静校正的初始模型进行迭代处理，最后得到最终的近地表速度-深度模型和静校正值.根据以上处理流程，我们建立了适合于川东北山地三维复杂地表地震资料的静校处理正方法，并在实际生产过程中取得了良好的效果. 相似文献
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低信噪比转换波地震资料静校正(英文) 总被引：1，自引：0，他引：1
Converted waves have slow velocity and low signal-to-noise ratio. It is also difficult to pick first-breaks and bin the common-conversion-points （CCP）. Some statics methods, which work well for P-wave data, can＇t be effectively used for solving convertedwave statics problems. This has become the main obstacle to breakthroughs in convertedwave data processing. To improve converted-wave static corrections, first, a statics method based on the common-receiver-point （CRP） stack is used for the initial receiver static correction to enhance the coherency of the CRP stack. Second, a stack-power-maximization static correction which improves the continuity of the CCP stack is used for detailed receiver statics. Finally, a non-surface-consistent residual moveout correction of the CCP gathers is used to enhance the stack power of reflection signals from different depths. Converted-wave statics are solved by the joint use of the three correction methods. 相似文献
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In the case of onshore data sets, the acquired reflection events can be strongly impaired due to rough top‐surface topography and inhomogeneities in the uppermost low‐velocity layer, the so‐called weathering layer. Without accounting for these influences, the poor data quality will make data processing very difficult. Usually, the correction for the top‐surface topography is not perfect. The residuals from this correction and the influence of the weathering layers lead to small distortions along the reflection events. We integrated a residual static correction method into our data‐driven common‐reflection‐surface‐stack‐based imaging workflow to further eliminate such distortions. The moveout‐corrected traces and the stacked pilot trace are cross‐correlated to determine a final estimate of the surface‐consistent residual statics in an iterative manner. As the handling of top‐surface topography within the common‐reflection‐surface stack is discussed in a separate paper in this special issue, the corresponding residual static correction will be explained in more detail. For this purpose, the results obtained with a data set from the Arabian Peninsula will be presented. 相似文献
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剩余静校正的目的是消除地震道中由近地表因素造成的静态剩余时差的影响,通常以时差的四因子分解模型为基础建立剩余静校正方程组,并采用迭代求解方法获得剩余静校正量。但实际上,由于地层的倾斜,时差中还应包含横向和纵向倾角项,因此本文首先对剩余校正的理论模型进行了改进,提出了以扩展面元为计算单元的时差分解六因子模型。又由于地层的走向具有局部线性性,因此剩余动校正项,横向及纵向倾角项系数仅在一些给定的面元上计 相似文献
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Static shifts from near‐surface inhomogeneities very often represent the key problem in the processing of seismic data from arid regions. In this case study, the deep bottom fill of a wadi strongly degrades the image quality of a 2D seismic data set. The resulting static and dynamic problems are solved by both conventional and common‐reflection‐surface (CRS) processing. A straightforward approach derives conventional refraction statics from picked first breaks and then goes through several iterations of manual velocity picking and residual statics calculation. The surface‐induced static and dynamic inhomogeneities, however, are not completely solved by these conventional methods. In CRS processing, the local adaptation of the CRS stacking parameters results in very detailed dynamic corrections. They resolve the local inhomogeneities that were not detected by manual picking of stacking velocities and largely compensate for the surface‐induced deterioration in the stack. The subsequent CRS residual statics calculations benefit greatly from the large CRS stacking fold which increases the numbers of estimates for single static shifts. This improves the surface‐consistent averaging of static shifts and the convergence of the static solution which removes the remaining static shifts in the 2D seismic data. The large CRS stacking fold also increases the signal‐to‐noise ratio in the final CRS stack. 相似文献
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Static correction is a common step in a seismic data proccessing flowchart for land data. Here we propose a new algorithm for automatic short‐period static correction. The algorithm is based on the assumption that seismic events after short‐period static correction should be locally plane nearly everywhere. No other assumptions are made. Therefore the proposed method does not require a preliminary velocity analysis. The algorithm consists in two main parts: evaluation of second spatial differences of trajectories and subsequent regularized integration of these differences. The proposed method proves its robustness and shows results comparable with conventional residual static correction based on improving common‐midpoint stacking. In contrast to the conventional residual static, the proposed algorithm can estimate short‐period statics in complex cases where common‐midpoint stacking fails because of non‐hyperbolic events. 相似文献
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我国北方地区黄土塬覆盖区的静校正问题是地震数据处理中的难点问题之一.黄土塬表层覆盖巨厚黄土，高差起伏较大，地震静校正问题严重；而且黄土塬覆盖区的潜水面普遍较深，常规折射静校正方法无法取得令人满意的处理效果.本文针对黄土塬覆盖区的静校正难题，研究层析反演静校正方法在黄土塬地区的适用性和可靠性.层析反演静校正利用地震波初至走时数据、通过迭代反演的方法构建速度模型，进而依据所得的近地表速度模型对地震数据进行静校正处理.本文的迭代反演采用同步迭代重构算法（SIRT），并且对同步迭代重构算法进行了改进，使得层析反演的迭代过程趋于稳定.但是，因为黄土塬覆盖区地表高程的横向变化剧烈，相邻检波点的高差及其静校正量有时差异很大，在运用层析静校正求取长波长静校正量的同时，还需采用初至波剩余静校正方法求取短波长静校正量.实例证明，综合应用依据初至波走时数据的层析静校正和剩余静校正方法，同时计算长波长和短波长的静校正量，能够有效地解决黄土塬覆盖区实际地震资料的静校正问题. 相似文献