地球物理学进展 ›› 2018, Vol. 33 ›› Issue (3): 1176-1183.doi: 10.6038/pg2018BB0297

• 应用地球物理学Ⅰ(油气及金属矿产地球物理勘探) • 上一篇    下一篇

复杂地表区叠前深度偏移近地表速度应用技术研究

赵玲芝1,2,冯许魁2,祖云飞3,张建中1,金守利4   

  1. 1. 中国海洋大学海洋地球科学学院,山东青岛 266100
    2. 东方地球物理公司研究院,河北涿州 072750
    3. 东方地球物理公司采集技术支持部,河北涿州 072750
  • 收稿日期:2017-06-26 修回日期:2018-02-05 出版日期:2018-06-20 发布日期:2018-08-23
  • 作者简介:第一作者简介 赵玲芝,女,1970年生,高级工程师,主要从事叠前成像技术的研究与应用工作.(E-mail: 843422508@qq.com)
  • 基金资助:
    国家科技重大专项(2017ZX05018-003)

Applied research of the complex near-surface velocity in the depth migration

ZHAO Ling-zhi1,2,FENG Xu-kui2,ZU Yun-fei3,ZHANG Jian-zhong1,JIN Shou-li4   

  1. 1. Ocean University of China, Shandong Qingdao 266100, China
    2. Geophysical Research Institute, BGP, Hebei Zhuozhou 072750, China
    3. Department of Acquisition Techniques Support, BGP, Hebei Zhuozhou 072750, China4. Research and Development Center,BGP,Hebei Zhuozhou 072750, China
  • Received:2017-06-26 Revised:2018-02-05 Online:2018-06-20 Published:2018-08-23

摘要:

随着基于“真地表”叠前深度偏移技术的实施,偏移速度需要由浅表层到深层开始建立,而浅表层的速度一般是利用初至层析技术反演得到,但初至层析技术具有多解性和等效性,这种特性对于静校正量的计算是合理的,但对于叠前深度偏移的速度而言则是不合适的,它直接影响深度偏移射线路径的走向及深层速度迭代的精度.为了提高浅表层速度应用的合理性,本文开展了详细的研究,通过研究发现:参与初至层析的炮检距范围是影响初至反演近地表速度多解性的主要原因,为了选取合适的能够用于叠前深度偏移的近地表速度模型,根据数值模型分析的结果,形成了基于优化炮检距的大炮初至层析近地表速度的选取及应用技术.通过应用该技术,选取的速度与真实速度比较接近,达到了提高近地表速度反演精度和应用合理性的目的,为叠前深度偏移近地表速度模型的合理选取提供了技术依据.

关键词: 深度偏移, 大炮初至, 层析反演, 速度模型, 复杂地表区

Abstract:

As the implementation of the “real” surface datum prestack depth migration technology, the migration velocity needs to set up from the shallow to depth. In general, the shallow velocity is usually obtained by first arrival tomography inversion technique. But this technology has multiple solutions and equivalence for the velocity model which is reasonable for the statics calculation and not appropriate for prestack depth migration. The reason is that this model can directly influence the ray path and direction in the depth migration, as well as the deeper velocity precision. In order to improve the application rationality of the near surface velocity, this paper has carried out detailed research. Through the research, we found that the offset range has the main influence to the multiple solutions of the near-surface velocity in the first arrival tomography. In order to select the right model which can be used to be near-surface velocity model of pre-stack depth migration, the paper has formed technology selection and application strategy of the first break tomography inversion based on the optimization offset according to the results of the theory model analysis. Through the application of the technology, we found that the selection velocity is close to the actual velocity. And the accuracy of the near-surface velocity have risen. The rationality of the method is proved. The purpose of application for near-surface velocity model of pre-stack depth migration has achieved.

Key words: depth migration, first break, tomography inversion, velocity model, complex surface area

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