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适于窄线三维地震资料的面炮方法 总被引：4，自引：6，他引：4
用小孔径波动方程叠前深度偏移完成大面积数据的成像，不仅总的计算量较大，而且成像畸变较严重。为了进行大孔径波动方程叠前深度偏移，必须将实际的小孔径资料合成大孔径资料，并解决大孔径资料的成像方法。AMO等合成孔径方法，数据合成方式简单，但成像方法是近似的且较复杂。面炮方法从理论上讲数据合成方法较简单，成像方法是精确的且较简单，但其应用适用于远道振幅比近道弱很多的情况。在窄线三维地震资料情况，其联络测线方向不易满足面炮应用条件。针对这种情况，本文将最小二乘原理应用于波场成像，提出适用窄线三维地震资料的面炮方法。为了解三维波动方程叠前深度偏移的面炮方法解决复杂油气藏的可行性、所需计算资源和成像效果，我们利用大庆SW地区三维地震资料进行了实验研究。通过研究，我们获得了面炮方法的实际效果，获得了所需计算资源的测试数据。对实际效果的分析对比表明，面炮方法是一种三维波动方程叠前深度偏移的快速方法，有较好应用前景。 相似文献
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盐丘模型 推覆体模型 波动方程 叠前深度偏移 总被引：4，自引：0，他引：4
三维波动方程叠前深度偏移是复杂介质中进行构造成像、弹性参数反演的重要环节.由于其技术实现不仅涉及波场延拓理论的创新，而且需要大规模计算，因而研究难度较大. 本文以实验效果的取得为目的，完整地实现了SEG/EAEG盐丘和推覆体模型的三维波动方程辛几何算法的叠前深度偏移成像计算. 文中详细考察了所研制的波动方程三维叠前深度偏移软件系统及其对复杂地质构造的成像能力. 具体包括：1）对于盐丘模型，文中讨论了成像参数的选择、地震子波对成像精度的影响、完成二维及三维叠前深度偏移的比较；2）对推覆体模型，文中进行了脉冲响应测试；3）由两个模型的成像结果可见本文的波动方程三维叠前深度偏移软件系统已具有适应强速度横向变化、复杂构造的成像能力. 相似文献
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三维波动方程叠前深度偏移是复杂介质中进行构造成像、弹性参数反演的重要环节．由于其技术实现不仅涉及波场延拓理论的创新,而且需要大规模计算,因而研究难度较大．本文以实验效果的取得为目的,完整地实现了SEG／EAEG盐丘和推覆体模型的三维波动方程辛几何算法的叠前深度偏移成像计算．文中详细考察了所研制的波动方程三维叠前深度偏移软件系统及其对复杂地质构造的成像能力,具体包括：1)对于盐丘模型,文中讨论了成像参数的选择、地震子波对成像精度的影响、完成二维及三维叠前深度偏移的比较;2)对推覆体模型,文中进行了脉冲响应测试;3)由两个模型的成像结果可见本文的波动方程三维叠前深度偏移软件系统已具有适应强速度横向变化、复杂构造的成像能力。 相似文献
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Kirchhoff积分叠前时间偏移应用波动方程的Kirchhoff积分解实现地下反射层的偏移问题,该技术应用所有偏移距的地震资料,能适应纵横向速度变化较大的情况,是复杂地区地震资料成像的较理想的方法.叠前时间偏移是对偏移处理和偏移速度修改的一个迭代过程,偏移速度的精度直接影响到偏移效果.对大庆油田古龙断陷某工区的三维地震资料,应用叠前时间偏移技术进行成像处理,对于埋深较大的目的层,断陷结构复杂,介质的各向异性较为严重,所以应用考虑各向异性参数的速度修改公式,得到较为精确的偏移速度体,进而保证偏移CRP道集拉平,得到成像良好的偏移数据体.实际地震数据偏移处理结果表明叠前时间偏移技术可对复杂构造的地震数据准确成像,可在古龙地区断陷地层勘探中推广应用. 相似文献
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复杂构造地震成像主要取决于叠前地震数据品质、偏移速度可靠性和偏移算子成像精度. 库车坳陷异常复杂的近地表条件导致极低信噪比的地震采集数据. 该区逆冲推覆高陡构造刺穿盐体大面积分布, 盐层厚度变化大、顶底面形态复杂, 盐下断裂带破碎、小断块发育, 形成异常复杂的地震成像问题. 本文重点研究三个关键环节:(1)精细的叠前地震预处理研究: 根据该区地震地质复杂性和地震资料特征, 采用一些新的方法技术和技术组合从振幅与时移的大、中、小尺度变化三个层次来解决资料信噪比问题, 重建深部反射信号; (2)三级偏移速度分析研究:利用库车坳陷盐刺穿逆冲推覆构造建模理论及变速成图配套技术解决叠前时间偏移速度场时深转换问题,利用井约束低频速度地震迭代反演技术解决连井层速度场与偏移速度场的融合问题,实现从DMO速度分析、叠前时间偏移速度分析到叠前深度偏移速度分析的有机衔接,建立拓扑结构相对保持的叠前深度偏移速度模型;(3)基于退化Fourier偏移算子的半解析波动方程叠前时间和深度偏移研究, 极大地改善了地震偏移过程中高波数波的成像问题. 通过对库车坳陷大北、博孜、却勒、西秋4和西秋10等复杂高陡构造的叠前时间和深度偏移地震成像处理,取得了较好的应用效果. 相似文献
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受地下复杂构造和地震数据采集系统的影响，使地震波对地下目标的照明出现不均匀性，地震采集系统难以有效地获取地下某些目标的反射信息，进而使数据偏移成像在这些目标体上出现成像阴影. 根据波场和Green函数的窗口Fourier框架展开，利用角度域波动方程偏移成像和波动方程照明分析，并结合波动方程反演理论，提出一种角度域波动方程偏移成像阴影照明补偿方法. 这种补偿方法能同时考虑地震数据采集系统和波场传播路径对偏移成像的影响，消除复杂构造区的偏移成像阴影，改进波动方程叠前深度偏移成像在复杂构造区的成像效果. 相似文献
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The semi‐automated detection of objects has been quite successful in detecting various types of seismic object, such as chimneys. The same technique can be applied successfully to detect faults in 3D seismic data. We show that several different attributes – among others, similarity, frequency and curvature, all of which potentially enhance the visibility of faults – can be combined successfully by an artificial neural network. This results in a fault ‘probability’ cube in which faults are more continuous and noise is suppressed compared with single‐attribute cubes. It is believed that the fault‐cube can be improved further by applying image‐processing techniques to enhance the fault prediction. 相似文献
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滕学军 《CT理论与应用研究》1995,4(1):10-14
本文对煤矿井下巷间地震波透射观测资料在平滑弯曲射线的基础上，利用联合迭代法（ＳＩＲＴ）进行煤体波速场的反演成像，并结合数值计算结果给以验证。其结果表明：采用平滑弯曲射线追中学地震波射线可以大大提高成像质量；地震层析成像技术用于探测煤体中的构造是一种有效且可行的方法。 相似文献
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Tao Wang Han-Dong Tan Zhi-Qiang Li Kun-Peng Wang Zhi-Ming Hu Xing-Dong Zhang 《应用地球物理》2016,13(3):553-560
The Z-Axis tipper electromagnetic (ZTEM) technique is based on a frequency-domain airborne electromagnetic system that measures the natural magnetic field. A survey area was divided into several blocks by using the Maxwell’s equations, and the magnetic components at the center of each edge of the grid cell are evaluated by applying the staggered-grid finite-difference method. The tipper and its divergence are derived to complete the 3D ZTEM forward modeling algorithm. A synthetic model is then used to compare the responses with those of 2D finite-element forward modeling to verify the accuracy of the algorithm. ZTEM offers high horizontal resolution to both simple and complex distributions of conductivity. This work is the theoretical foundation for the interpretation of ZTEM data and the study of 3D ZTEM inversion. 相似文献
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HVSR prospecting in multi-layered environments: An example from the Tyrnavos Basin (Greece) 总被引：1，自引：0，他引：1
The Tyrnavos Basin (Central Greece) is an E-W trending graben bordered by two major antithetic sets of right-stepping dip-slip normal faults that began forming during Middle Pleistocene as a consequence of the N-S extension which affected the whole Aegean Region. This Quaternary structure is superimposed on the Pliocene-Early Pleistocene NW-SE trending Larissa Basin, approximately 700–800 m deep. Seismic activity is instrumentally well documented within and surrounding the investigated area. Based on structural, morphotectonic and palaeoseismological data, several structures previously characterised as active faults have been investigated by applying the HVSR method. This method is commonly used to map the thickness of sedimentary layers in a basin based on the variation of the fundamental 1-D frequency. The polyphased structural evolution and the consequently complex geological setting do not allow for the contouring of a unique continuous surface. We therefore developed a new interpretation technique for statistically significant HVSR peaks, in order to obtain 2-D sections that can be interpreted in a seismic-like fashion. We applied this technique across the major active faults bordering the basin. The results confirm their occurrence at depth and document the important vertical component of displacement. 相似文献
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转换波方位各向异性裂缝检测技术研究及应用 总被引：1，自引：0，他引：1
HTI裂缝各向异性介质中,转换波随方位角的变化比较复杂,目前还没有解析公式可以表达其变化特征,只能通过物理实验或数值模拟来分析其应用的可能性.数值模拟结果表明,转换波在裂缝各向异性介质中传播时,其R分量和T分量的振幅属性都具有明显的方位各向异性特征,R分量振幅方位各向异性拟合椭圆的长轴方向指示裂缝方位,这与纵波方位各向异性特征相似;根据P波AVAZ方位各向异性分析原理,对转换波R分量振幅方位各向异性曲线进行方位椭圆拟合,寻找椭圆的长轴方向,即裂缝主方位,再由P波AVAZ技术中振幅响应与炮检方向和裂缝走向之间的夹角关系式得到裂缝的发育密度,从而构建转换波方位各向异性AVAZ裂缝检测技术.该技术已用于川西新场气田某区块的裂缝储层预测,取得了较好的应用效果. 相似文献
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Mohammad Talebi Abbas Sivandi-Pour Ghasem-Ali Ahmadi Ehsan Noroozinejad Farsangi Shamseddin Esmaeili Mohammad-Javad Banimahdi-Dehkordi Hamidreza Safizadeh Mahdieh Akbarpoor Ehsan Ebrahimi Rabe Sharifi Rad Manoochehr Fallah 《地震科学（英文版）》2022,35(2):122-137
Fault lineaments are the main input data in earthquake engineering and seismology studies. This study presents a digitally-based active fault map of the Kerman region in central-east Iran which experienced several devastating earthquakes on poorly exposed and/or not identified active faults. Using Landsat 8 data, we have carried out the image-based procedures of fault mapping, which include applying the contrast stretching technique, the principal component analysis, the color composite technique, the spectral rationing, and creating the false-color composite images. Besides, we have cross-checked the resulting map with the geological maps provided by the Geological Survey of Iran to decrease the associated uncertainties. The resulting map includes 123 fault segments, still, a part of which has been expressed in the previously compiled active-fault maps of Iran. Indeed, the new one is mapping the poorly exposed active faults, so-called secondary faults, which are able to produce strong events. These faults are primarily associated with poorly defined areas that accommodate low levels of seismicity; however, sporadic strong events are likely to occur. It has also been investigated that these kinds of faults are seismogenic and are able to produce destructive events. In total, the outcome of this study can also be jointed with seismic studies for investigating parts of the earthquake activity in central-east Iran, in particular for the fault-based approaches in impending earthquake-resistant buildings. 相似文献
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运用ＣＴ技术中的傅利叶重建法，根据任意所给的两个初始速度模型，用几组平行射线束进行扫描，采集走时数据，并利用走时数据反演速度图象．反演结果与初始模型比较两者基本相符合。由此证明，傅利叶重建法在一定条件下可以用来反演地壳速度结构，并可得到较好的结果．这种方法是ＣＴ技术应用于地学研究的一种新的尝试． 相似文献
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The transient analysis of dam–reservoir systems by employing perfectly matched layers has been investigated. In previous studies, boundary conditions of the PML region in the reservoir have been neglected. In this paper, they are incorporated completely in the formulation. Moreover, a technique is introduced to involve the effect of incident waves caused by vertical ground motions at the reservoir bottom in the analysis. Performing several numerical experiments indicates that applying boundary conditions of the PML domain and utilizing the proposed method for vertical excitation cases reduce the computational cost significantly and make the PML method a very efficient approach for the transient analysis of dam–reservoir systems. 相似文献
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Numerical investigations have been carried out on suitable interpretation schemes for gravity, based upon Backus-Gilbert inverse theory. A two-dimensional linear model consisting of horizontal prisms (grid shape) has been adopted for interpretation of gravity profiles. An inversion technique, which uses a linear approach suitable for rapid computation, and studies with synthetic bodies have led to improvements in the method, mainly by applying weighting factors, which improve the solution in the final stages of computational work. Gravity data from the well-known Cyprus island positive anomaly were inverted to demonstrate the feasibility of the method. 相似文献
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Jin Xueshen Liu Yunqing Hu Mingqing Liu Zhihui Nie Lei and Zhang FengzhiSeismological Bureau of Hebei Province Shijiazhuang China Jianghan University Wuhan China 《中国地震研究》1998,(1)
I.INTRODUCTION A great deal of 1ife lOSS data from the strong earthquakes.especially the total deathtoll in eachstrong shock,has been accumulated in some densely populated areas.In the record ofthe injuries anddeaths from earthquakas,the death mark iS easier to be judged SO that Bhth(1978)suggested chat thedeathtoll would be used as a mark of the level of the earthquake destruction.He considered that insome cases.the deathtoll of life would be more effective than the destruction number… 相似文献