A linear traveltime interpolation method with hybrid meshes for VTI medium under rugged interface conditions

WANG Qi1,2 LI Qingchun WANG Zhiqi

(1.College of Geology Engineering and Geomatics, Chang’an University , Xi’an, Shaanxi, China 710054)
(2.China National Aviation Fuel Northwest China Company, Xi’an, Shaanxi , China 710082)
【Knowledge Link】direct wave; primary wave

【Abstract】In order to calculate the seismic wave traveltime in VTI medium under rugged interface conditions, we divide a model with a hybrid mesh composed by rectangular meshes and irregular quadrilateral meshes to better fit rugged interface conditions. In the hybrid mesh, the relationship between group velocity and group angle is transformed into the relationship between group velocity and interpolated point coordinates to find the local traveltime. Then with the multi-stage multi-step calculation technique, the ray tracing algorithm is extended to VTI medium to realize the traveltime calculation of seismic waves (first arrival, reflection, multiple reflection, multiple transmission conversion, and multiple reflection conversion) in VTI medium. Compared with the irregular cell shortest path method, the numerical simulations show that the proposed algorithm is more accurate and can better adapt the complex-structure models.

【Keywords】 vertical transverse isotropic ; ray tracing ; rugged interface ; hybrid mesh ; seismic wave traveltime ;

【DOI】

【Funds】 National Natural Science Foundation of China (41874123) Geologic Research Project of China Geological Survey (DD20160060) Fundamental Research Funds for the Central Universities (300102268401)

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This Article

ISSN:1000-7210

CN: 13-1095/TE

Vol 53, No. 06, Pages 1175-1187+1111

December 2018

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Article Outline

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Abstract

  • 1 Introduction
  • 2 LTI ray tracing in hybrid mesh modeled VTI media with irregular surface
  • 3 Numerical examples
  • 4 Conclusions
  • References