Acoustic field simulations of logging while drilling by cylindrical finite difference with variable grids

作     者：Pan Yue He Xiao Chen Hao Wang Xiu-Ming 潘钥;何晓;陈浩;王秀明

作者机构：State Key Laboratory of AcousticsInstitute of AcousticsChinese Academy of SciencesBeijing 100190China University of Chinese Academy of SciencesBeijing100049China Beijing Engineering Research Center of Sea Deep Drilling and ExplorationBeijing 100190China 

出 版 物：《Applied Geophysics》 (应用地球物理（英文版）)

年 卷 期：2022年第19卷第1期

页      面：11-28,143页

核心收录：

学科分类：081801[工学-矿产普查与勘探] 081802[工学-地球探测与信息技术] 08[工学] 0818[工学-地质资源与地质工程] 

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.12174421 11774373 11734017 and 42074215) 

主　　题：acoustic detection finite difference variable grid method scattering and refl ection cylindrical guided wave 

摘      要：This study proposes an elastic finite difference(FD)time domain method with variable grids in three-dimensional cylindrical *** calculations will diverge and become less accurate by conventional cylindrical FD as the grid size gradually becomes more extensive with the increasing *** prevent grids from being too coarse in far fields,we compensate for the grid cell infl ation by refi ning the grid step in the azimuthal *** variable grid FD in the cylindrical coordinate systems has a higher effi ciency in solving acoustic logging while drilling(LWD)problems because the grid boundaries are consistent with those of the drill collar and the *** proposed algorithm saves approximately 94%of the FD grids,80%of the computation time,and memory with a higher calculation accuracy than the FD on rectangular grids for the same *** also calculate the acoustic LWD responses of the fl uid-fi lled borehole intersecting with *** ections are generated at the fractures,which can be equivalent to an additional scattering *** mode conversions between the collar and the Stoneley waves are *** Stoneley spectra are more sensitive to the ***,the logs in a heterogeneous formation with two refl ectors far from the borehole are modeled,and a means of estimating the azimuth of geological interfaces from refl ections is proposed.