A grid-variable finite-difference fast marching method
You-Juan HE1, Yu-Lei QIAO2, Li-Juan HOU3, Jun ZHU4, Gang GAO1, Peng WANG1
1. Key Laboratory of Exploration Technologies for Oil and Gas Resources(Yangtze University),Ministry of Education,Wuhan 430100,China 2. Shengli Oil Field Exploration and Development Research Institute,SINOPEC,Dongying 257000,China 3. No.1 Oil Production Plant,Qinghai Oil Field,PetroChina,Haixi 816400,China 4. No.1 Oil Production Plant,Northwest Oilfield Company,SINOPEC,Luntai 841600,China
The accuracy of seismic wave traveltimes directly affects the reliability of research results in such fields as seismic inversion,pre-stack migration imaging and tomography.Therefore,it is of great significance to study the improvement of the accuracy of seismic wave traveltimes.Based on the double grid technology,this paper comes up with a fast marching method (FMM) based on the grid-various finite-difference scheme to calculate the traveltimes of seismic wave.It analyzes the advantages and applicability of the grid-various finite-difference FMM by the forward simulation of uniform model as well as the existence of high-speed anomalous body model,Marmousi model.The results show that the corner points need to be included in the calculation when the traveltimes are calculated by using Eikonal equation so as to reduce the error.Under the background of uniform model,the grid-variable finite-difference FMM has the same advantages as the double grid FMM.Nevertheless,under the background of the existence of high-speed anomalous body model,the double grid FMM may violate the law of wavefront expansion to cause a greater error.The grid-variable finite-difference FMM does not have such a problem,and its advantage is remarkable.Therefore,this method is an effective way to improve the accuracy and efficiency of traveltime calculation,which not only enhances the applicability of the FMM but also expands the application range of grid-various technology.
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