改进型迎风有限差分法计算三维地震波走时  

Research on calculation of 3D seismic-wave travel time based on improved upwind finite difference method

作　　者：巴素玉[1] 时瑞坤[1] 孙小东[2] 蒋润 BA Suyu;SHI Ruikun;SUN Xiaodong;JIANG Run(Geophysical Research Institute,Shengli Oilfield Company,SINOPEC,Dongying 257022,Shandong;School of Geosciences,China University of Petroleum(East China),Qingdao 266580,Shandong)

机构地区：[1]中国石化胜利油田分公司物探研究院,山东东营257022 [2]中国石油大学(华东)地球科学与技术学院,山东青岛266580

出　　处：《长江大学学报（自然科学版）》2023年第2期45-50,共6页Journal of Yangtze University(Natural Science Edition)

基　　金：山东省自然科学基金面上项目“深层粘滞性介质弹性波逆时偏移”(ZR2020MD048);中国石化地球物理重点实验室开放基金项目“基于YOLO和CNN-LSTM复合神经网络的智能速度拾取”(33550006-22-FW0399-0026);国家自然科学基金项目“基于三角网格剖分模型的高斯波包立体层析成像”(41874118)。

摘　　要：走时计算在速度分析、基准面校正、层析反演及射线类偏移等领域有广泛的应用。为了提高走时计算的精度和稳健性,在常规有限差分算法的基础上,进一步推出基于局部平面波前近似的程函方程求解方法,即改进型迎风有限差分法,用来计算出三维初至走时。改进型迎风有限差分法对散射波和首波做了适当处理,不存在常规有限差分算法的阴影区、焦散区等问题。从模型试算的效果可以看出,该方法灵活性好,适用于强变速的情况,对于盐丘模型,即使不做平滑处理也能稳健地进行走时计算。改进型迎风有限差分法计算三维地震波走时适用于复杂地质构造地区的走时计算,具有广阔的应用前景。Travel time calculation has been widely used in velocity analysis,datum correction,tomography inversion and ray migration.In order to improve the accuracy and robustness of travel time calculation,based on the conventional finite difference algorithm,an eikonal equation solution method based on local plane wavefront approximation,namely the improved upwind finite difference method,was further proposed in this paper to calculate the three-dimensional first break travel time.The calculation method of the improved upwind finite difference method has properly treated the scattered wave and head wave,and there will be no shadow area,caustics area and other problems of the traditional finite difference algorithm.It can be seen from the result of model test that the method in this paper is flexible and suitable for the case of strong velocity change.For the salt dome model,the travel time can be calculated robustly even without smoothing.The improved upwind finite difference method for 3D seismic-wave travel time calculation proposed in this paper is suitable for travel time calculation in complex geological structure areas,and has broad application prospects.

关 键 词：迎风型有限差分法 程函方程 初至走时 焦散区 

分 类 号：P631.44[天文地球—地质矿产勘探]