First break traveltime tomographic imaging based on the eikonal equation in VTI medium

ZHANG Kai1,2 CHEN Junyi1,2 ZHU Baihang1 LI Zhenchun1,2 DING Pengcheng1

(1.School of Geosciences, China University of Petroleum (East China) , Qingdao, Shandong, China 266580)
(2.Laboratory of Marine Mineral Resources Evaluation and Detection Techniques, National Laboratory for Marine Science and Technology, Qingdao, Shandong, China 266061)
【Knowledge Link】Fast marching method

【Abstract】The first break traveltime tomography is an effective method for the inversion of anisotropic parameter. Its difficulties are the calculation of first break traveltime and joint inversion of anisotropic parameters in VTI medium. In this paper, we use, NMO velocity, and non-elliptic coefficient to characterize the anisotropy. The ray tracing based on Runge-Kutta algorithm is used to calculate Fréchet kernel. According to the group slowness approximate expressions, the Fréchet kernels of these three parameters are derived. In order to overcome the magnitude between the three parameters, a double-round strategy is employed. The least squares orthogonal decomposition (LSQR) algorithm is used to carry out the joint inversion of the two methods. The numerical simulations show that the proposed method has better inversion accuracy than the Thomsen Kutta algorithm is not only applicable to isotropic medium but also to VTI medium.

【Keywords】 VTI medium; eikonal equation; first break traveltime tomography; Fréchet kernel; Thomsen parameter;

【DOI】

【Funds】 National Science and Technology Major Project on Oil and Gas Development (2017ZX05032-003-002) Natural Science Foundation of Shandong Province (ZR2017MD014) Key Research and Development Program of Shandong Province (2018GHY115016) Innovative Scientific Research Program of China University of Petroleum (East China) (17CX02052)

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This Article

ISSN:1000-7210

CN: 13-1095/TE

Vol 53, No. 06, Pages 1218-1226+1112-1113

December 2018

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Abstract

  • 1 Introduction
  • 2 Principle
  • 3 Numerical simulation
  • 4 Conclusions
  • References