用线震源代替点震源模拟地震自激自收记录的几点探讨
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摘要
在进行地震波数值模拟时,往往需要模拟自激自收地震记录,一炮一道计算很费时间。如果用线震源代替点震源来进行模拟计算,则大大提高计算效率。本文以二维的一阶速度—应力交错迭代计算的方程组为理论基础,分别采用点震源和线震源对水平、倾斜两层介质模型以及断层模型进行了正演模拟计算。从直观的反射波波形形态、反射时间大小以及频率特性等方面进行了对比分析。另外,还从球面波(点震源)与柱面波(线震源)的联系方面,探讨了将球面波通过反滤波转换为柱面波的可能性。研究结果表明,如果只考虑反射时间以及频率的相对变化,则线震源可以替代点震源模拟自激自收地震记录。
When numerically simulating the seismic wave,the zero offset seismic records are usually needed to be simulated.Calculation for each channel and shot is time-consuming.If the thread source replaces point source to simulate calculation,computation efficiency is improved greatly.Based on the 2Dfirst derivative of velocity and stress staggered grid iteration calculation equations,two medium layers,horizontal and oblique,and fault model are forward simulated calculation by the use of the thread source and point source.The visual image of form of reflection wave,the size of the reflection time,frequency characteristicand so on have been compared and analyzed.In addition,in terms of the relationship between the spherical wave(point source)and the cylindrical wave(thread source),the possibility that filter is used to inverse the spherical wave into the cylindrical wave is discussed.The results show that the thread source can replace point source to simulate zero offset seismic records taking only the reflection time and relative change off frequency into consideration.
When numerically simulating the seismic wave,the zero offset seismic records are usually needed to be simulated.Calculation for each channel and shot is time-consuming.If the thread source replaces point source to simulate calculation,computation efficiency is improved greatly.Based on the 2Dfirst derivative of velocity and stress staggered grid iteration calculation equations,two medium layers,horizontal and oblique,and fault model are forward simulated calculation by the use of the thread source and point source.The visual image of form of reflection wave,the size of the reflection time,frequency characteristicand so on have been compared and analyzed.In addition,in terms of the relationship between the spherical wave(point source)and the cylindrical wave(thread source),the possibility that filter is used to inverse the spherical wave into the cylindrical wave is discussed.The results show that the thread source can replace point source to simulate zero offset seismic records taking only the reflection time and relative change off frequency into consideration.
引文
[1]潘威,成景旺,闫立爽.二维弹性波方程频率空间域有限差分正演研究[J].工程地球物理学报,2013,10(6):858~862.
[2]郑昭,王志.裂缝介质地震波场特征正演模拟分析[J].工程地球物理学报,2013,10(4):487~492.
[3]黄诚,杨飞,李鹏飞.利用正演模拟识别各类地震假象[J].工程地球物理学报,2013,10(4):493~496.
[4]黄琪嵩,于师建,郭龙.砂岩双相介质孔隙度地震波场数值模拟研究[J].工程地球物理学报,2014,11(1):95~100.
[5]裴正林.双相各向异性介质地震波传播交错网格高阶有限差分法模拟[J].石油地球物理勘,2006,41(2):137~143.
[6]孙卫涛,杨慧珠.双相各向异性介质地震波场有限差分正演模拟[J].固体力学学报,2004,25(1):21~28.
[7]吴国忱,王华忠.波场模拟中的数值频散分析与校正策略[J].地球物理学进展,2005,20(1):58~65.
[8]张省,何兵寿,王玉凤.VTI介质交错网格FCT有限差分数值模拟[J].工程地球物理学报,2012,9(5):565~571.
[9]杜世通.地震波动力学理论与方法[M].山东东营:中国石油大学出版社,2009.
[2]郑昭,王志.裂缝介质地震波场特征正演模拟分析[J].工程地球物理学报,2013,10(4):487~492.
[3]黄诚,杨飞,李鹏飞.利用正演模拟识别各类地震假象[J].工程地球物理学报,2013,10(4):493~496.
[4]黄琪嵩,于师建,郭龙.砂岩双相介质孔隙度地震波场数值模拟研究[J].工程地球物理学报,2014,11(1):95~100.
[5]裴正林.双相各向异性介质地震波传播交错网格高阶有限差分法模拟[J].石油地球物理勘,2006,41(2):137~143.
[6]孙卫涛,杨慧珠.双相各向异性介质地震波场有限差分正演模拟[J].固体力学学报,2004,25(1):21~28.
[7]吴国忱,王华忠.波场模拟中的数值频散分析与校正策略[J].地球物理学进展,2005,20(1):58~65.
[8]张省,何兵寿,王玉凤.VTI介质交错网格FCT有限差分数值模拟[J].工程地球物理学报,2012,9(5):565~571.
[9]杜世通.地震波动力学理论与方法[M].山东东营:中国石油大学出版社,2009.
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