地球物理学进展 ›› 2018, Vol. 33 ›› Issue (5): 1967-1973.doi: 10.6038/pg2018BB0216

• 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

复杂近地表三维初至波走时层析方法研究

王川1(),李振春2,李文燕1,张凯2,王兴军1,陈阳阳1   

  1. 1. 中国石油塔里木油田分公司勘探开发研究院,新疆库尔勒 841000
    2. 中国石油大学(华东)地球科学与技术学院,山东青岛 266580
  • 收稿日期:2017-12-26 修回日期:2018-08-11 出版日期:2018-10-20 发布日期:2019-01-11
  • 作者简介:王川,男,1985年生,工程师,2008年毕业于西南石油大学勘查技术与工程技术专业,长期从事速度研究与变速成图方法技术研究.
  • 基金资助:
    国家自然科学基金(41774133);塔里木油田分公司课题(041014110039)

3D first-arrival travel-time tomography based on complex near-surface model

WANG Chuan1(),LI Zhen-chun2,LI Wen-yan1,ZHANG Kai2,WANG Xing-jun1,CHEN Yang-yang1   

  1. 1. Exploration and Development Research Institute of Tarim Oilfield Company of Petro-China, Xinjiang Korla 841000, China
    2. School of Geosciences, China University of Petroleum(East China), Shandong Qingdao 266580, China;
  • Received:2017-12-26 Revised:2018-08-11 Online:2018-10-20 Published:2019-01-11

摘要:

复杂起伏地表条件下三维初至波走时层析速度建模方法是我国西部山地、沙漠地区地震资料处理的关键技术之一.传统的三维走时层析反演在应用中存在诸多问题:一是射线追踪技术固有的计算效率低、对复杂模型计算不稳定;二是对于大规模三维模型,Tikhonov正则化难以对零空间和欠定分量进行有效约束,造成迭代收敛速度缓慢.本文首先在多模板快速推进算法(MSFM)走时计算的基础上,提出了一种新的射线追踪方法.整形正则化方法和共轭梯度法对反演方程进行了有效的约束,实现了初至波走时层析反演.三维理论模型实验和实际资料处理表明,该方法具有比传统射线走时层析方法更高的反演精度与迭代收敛速度.

关键词: 三维初至波走时层析, 敏感核函数, 多模板快速推进法, 起伏地表, 整形正则化

Abstract:

Highly efficient and accurate ray-tracing method in complex near-surface media have continuously been the key technique in three dimensional travel-time tomography. However, traditional algorithms utilized for travel-time tomography usually encounter problems when handling large 3D seismic data. First is the shortcomings inherited in the ray-tracing technique, such as the low computational efficiency and instability when strong velocity contrast exists in velocity model. Second, the disadvantages of traditional regularization algorithms lie in their low iterative convergence rate caused by the insufficient control on estimated model by the Tikhonov’s regularization, which could be detrimental for large 3D scale problems, when only few iterations are affordable. In this paper, we first develop the Multi-Stencils Fast Marching Method (MSFM) into 3D travel-time computation for complex media with topography. We propose a new algorithm for calculating the Fréchet derivative matrix based on MSFM. Additionally, we incorporate a shaping regularization into conjugate gradient algorithm to minimize the data misfit iteratively. Finally, the numerical experiments on 3D models and real data have demonstrated the higher accuracy and faster convergence of the proposed method compared to the classical algorithm.

Key words: 3D first-arrival travel-time tomography, fréchet matrix;, MSFM, irregular topography, shaping regularization

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