VSP地震资料逆时偏移方法研究

发布时间：2018-04-11 13:33

本文选题：VSP资料 + 逆时偏移　；参考：《东北石油大学》2015年硕士论文

【摘要】：传统VSP成像方法仅利用记录中的上行波,并将其视作一次反射进行成像,然而下行波并未得到应用。当地下存在高陡倾角构造时,下行波所包含的此类构造的反射信息将不能得到有效成像。并且由于上行波的照明有限,同时也将限制其成像的范围。与之相比,VSP逆时偏移理论上可对多种波(一次反射、多次波、棱柱波等)进行准确成像,无成像倾角限制。因此,VSP地震资料的丰富波场信息更适合于逆时偏移,其复杂的波场也将被充分利用,从而弥补传统方法的不足。本文首先对VSP观测方式进行简要介绍,并对VSP资料的特点进行了说明,阐明VSP资料对于复杂构造勘探的重要价值。其次,针对地震波场的数值模拟进行研究,对常规网格、变网格、频域正演以及两步法显示延拓等方法的理论给予简要说明,分析各自方法的优势,可在不同程度上提高波场数值模拟精度或效率。在存储方面,对逆时偏移的存储进行分析,通过采用相应的存储策略可在不影响精度的同时,减少逆时偏移对存储的过多依赖。在去噪方面,分析对比了不同的低频噪音压制方法。在计算方面,实现算法的GPU加速计算,通过GPU多卡并行来进行三维模型的计算,显著提高了算法的计算效率。然后对影响逆时偏移的各种因素进行分析,以提高成像效果。通过对复杂模型进行试算,验证了算法的实际效果。并将算法在Qt平台下进行集成,得到可移植的VSP偏移界面。最后,对全波形反演算法进行了探索性研究,为逆时偏移的速度建模提供保证。
[Abstract]:The traditional VSP imaging method only uses the recorded uplink wave and regards it as a reflection, but the downlink wave is not applied.When there is a high steep dip structure in the underground, the reflection information of such a structure contained in the downlink wave will not be able to be effectively imaged.And because the illumination of uplink wave is limited, it will also limit the range of imaging.In comparison with VSP inverse time migration, multiple waves (primary reflection, multiple, prism, etc.) can be accurately imaged in theory without the limitation of imaging inclination angle.Therefore, the rich wave field information of VSP seismic data is more suitable for inverse time migration, and its complex wave field will be fully utilized to make up for the shortcomings of traditional methods.In this paper, the VSP observation method is introduced briefly, the characteristics of VSP data are explained, and the important value of VSP data for the exploration of complex structures is expounded.Secondly, the numerical simulation of seismic wave field is studied. The theories of conventional grid, variable grid, frequency domain forward modeling and two-step method display continuation are briefly explained, and the advantages of each method are analyzed.The accuracy or efficiency of wave field numerical simulation can be improved in different degree.In the aspect of storage, the storage of inverse time offset is analyzed. By adopting the corresponding storage strategy, we can reduce the excessive dependence of inverse time offset on storage without affecting the accuracy.In the aspect of denoising, different methods of low frequency noise suppression are analyzed and compared.In the aspect of computation, the GPU accelerated computation of the algorithm is realized, and the computation of 3D model is carried out by GPU multi-card parallel, which improves the computational efficiency of the algorithm significantly.Then, various factors affecting inverse-time migration are analyzed to improve the imaging effect.Through the trial calculation of the complex model, the actual effect of the algorithm is verified.The algorithm is integrated on QT platform to obtain portable VSP migration interface.Finally, the full waveform inversion algorithm is studied in order to guarantee the velocity modeling of inverse time migration.
【学位授予单位】：东北石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P631.44

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