用P-SV波叠加剖面合成横波层速度剖面

本文从Zoeppritz方程的精确解出发,导出了P-SV波反射系数的高精度近似表达式,证明P-SV波的反射振幅正比于△V_s/V_s.这里,V_s为反财界面两侧横波层速度的平均值;△V_s为两侧横渡层速度的差值.文中将P-SV波共转换点水平叠加改进为共转换点拟合叠加,得到正比于△V_s/V_s的叠加振幅.仿照纵波勘探中的波阻抗技术,利用P-SV波拟会叠加剖面(或其偏移归位剖面)逐层向下递推反演,再加上适当的标定,便可获得横渡层速度剖面.

Deriving a S-wave interval-velocity section from P-SV wave stack section

The desirable approximate expression of P-SV wave refIection coefficient is deduced from the accurate solution of Zoeppritz's equation. Then,the reflection amplitude of P-SV wave is proved to be directly proportional to △V_s/V_s,where V_s is theaverage interval velocity of shear waves at the both sides of reflector,and △V_s is theinterval velocity difference of the shear waves.The horizontal stack of common conversion points of P-SV waves is changed into fitting stack of these comrnon conversion points to result in stacked amplitudes which are directly proportional to △V_s/V_s.People can obtain S-wave interval-velocity section by imitating wave impedancetechnique in P-wave exploration,namely,by rnaking downward layer by layer recursion inversion and calibration of fitting-stacked (or rnigrated) section of P-SVwaves.