Interferometric Imaging Of Walkaway VSP Data

In this paper, a new imaging method, which is called seismic interferometric imaging that based on optical interferometry principle, has been tested; seismic wave instead of leaser beam has been used. This method transforms the walkaway VSP data into surface seismic data that is equivalent in kinematics. Prestack migration and conventional seismic data processing method can be used to process the transformed seismic data(interferogram). Therefore, matured conventional seismic processing method could be used to image walkaway VSP data. The primary advantage of interferometric imaging method is the wider imaging extension and insensitivity to the receiver statics correction. We modeled the walkaway VSP data of a strata structure and a geological structure that a fault is included using acoustic equation finite difference method in this dissertation. The conventional primary reflection imaging method and interferometric imaging method were used to process the modeling data. Imaging result indicated that interferometric imaging method could get correct subsurface image and its imaging extension was about 3 times more than primary reflection imaging. Also, conventional surface seismic imaging method and interferometric imaging method were used to process transformed seismic data(diffraction-stack migration), both could get correct subsurface image. Finally, field walkaway VSP data was processed using the interferogram imaging method and satisfactory image was gained.