PSV波叠前反射点水平偏移

HORIZONTAL MIGRATION OF REFLECTION SPOTS OF PSV-WAVE BEFORE STACK

地质矿产部石油物探研究所

在PSV波勘探中,由于入射P波,反射SV波引起的传播路径不对称,使反射点偏离共中心点,浅层比深层偏得远;大炮检距比小炮检距偏得严重。如果不做这种偏离的校正,就不可能实现共反射点叠加。本文从理论上证明了PSV波射线轨迹的单调性;叙述了采用“网格移动法”在水平方向上做PSV波的运动学特征的偏移步骤,并且给出了一些实际算例。

In PSV-wave exploration, owing to the asymmetry of the ray-paths caused by the incident P-wave and the reflected SV-wave, the reflection spots would be deviated from the CMPs: the shallower the horizon, the more the deviation; the greater the offset, the more it would be deviated. If the deviation correction won't be made, the CRP-stack won't surely be carried out.It has been proved theoretically in this paper that the locus of the PSV-wave ray-paths was monotonic in character. The migration steps of extracting the kinematical characters of PSV-wave in horizontal direction by "grid shifting"were described. Some exampls of the real data were given.