摘要
高斯束逆时偏移是一种采用高斯束加权积分构建格林函数的逆时偏移算法,结合了逆时偏移的高精度和高斯束偏移的灵活性、高效性,能够面向目标成像。对于高斯束逆时偏移算法,成像精度很大程度上取决于初始参数的设置:当初始波束宽度较小时,浅层构造成像精度高,但波束宽度会随着距离增加快速发散,影响中深部成像效果;当初始波束宽度较大时,波束宽度沿射线路径变化比较缓慢,但会降低中心射线振幅及旅行时计算精度,进而影响成像质量。为此,将动态聚焦束思想应用于高斯束逆时偏移算法,通过选取合适束算子构建格林函数,进而通过格林函数实现正、反向波场延拓,最后通过正、反向波场的互相关求取成像结果,实现各向异性动态聚焦束逆时偏移。数值模型测试验证了算法的正确性和有效性。
Reverse time migration with Gaussian beams is a reverse time migration algorithm that uses Gaussian beam weighted integral to construct Green function.It integrates the flexibility and high efficiency of Gaussian beam migration and the accuracy of reverse time migration,which is capable of target imaging.The imaging quality of reverse time migration with Gaussian beams is highly dependent on initial parameters.When the initial beam width is small,the imaging accuracy of shallow structures is high.However,the beam width diverges rapidly as the distance increases,affecting the imaging effect of the middle and deep parts.When the initial beam width is large,the beam width changes slowly along the ray path but can reduce the calculation accuracy amplitude and travel time at the central ray,which thereby affects the imaging quality.In view of this,the idea of dynamically focused beams and the reverse time migration with Gaussian beams are combined.The Green function is constructed by the selection of an appropriate beam operator,with which the conti-nuation of forward and backward wave fields is rea-lized.Finally,the imaging results are obtained through the cross-correlation of forward and backward wave fields,and the anisotropic reverse time migration with dynamically focused beams is rea-lized.The correctness and effectiveness of the method are verified by numerical tests.
作者
肖建恩
李博
万城程
蔡杰雄
白英哲
李振春
XIAO Jian'en;LI Bo;WAN Chengcheng;CAI Jiexiong;BAI Yingzhe;LI Zhenchun(SINOPEC Geophysical Research Institute,Nanjing,Jiangsu 211103,China;Exploration&Development Research Institute of Henan Oilfield Company,SINOPEC,Zhengzhou,Henan 450000,China;School of Geosciences,China University of Petroleum(East China),Qingdao,Shandong 266580,China)
出处
《石油地球物理勘探》
EI
CSCD
北大核心
2021年第5期1086-1092,I0012,I0013,共9页
Oil Geophysical Prospecting
基金
中石化科技部项目“超深层碳酸盐岩储集体成像处理技术研究”(P21071-1)资助。
关键词
高斯束逆时偏移
动态聚焦束
格林函数
各向异性射线追踪
reverse time migration with Gaussian beam
dynamically focused beam
Green function
anisotropic ray tracing
