井间地震和逆VSP联合层析成像

Joint tomography of interborehole seismic data and inverse VSP data.

在研究井间地震和逆VSP联合层析成像时,充分考虑了坡射线在纵、横向非均习介质中的弯曲效应。首先采用打靶法进行两点射线追踪,用奇异值分解注解病态方程;然后设计了一个理论模型进行试验,并用上述方法对实际井间地震和逆VSP资料进行处理,获得令人满意的效果。当地下介质比较复杂时,利用射线追踪可能出现盲区。为了克服盲区给反演计算带来的影响,可对盲区政用直射线代替曲射线追踪。

The curvature effect of wave rays in vertically and horizontally-nonuniform medium must be considered in making joint tomography of interborehole seismic data and inverse VSP data. Desirable result can be achieved by performing dual-point ray tracing with the use of 'target practice 'method, solving for ill-conditioned equation with the aid of singular value decomposing, designing a theoretical model for test,and processing real interborehole seismic data and inverse VSP data according to this procedure. Ray tracing may result in blind zone in the case of complicated medium. In order to eliminate the trouble caused by the blind zone in inversion,we use straight-ray tracing over the blind zone instead of curved-ray tracing.