Cross-well reflection imaging at the Verkhnekamskoe potash deposit

We propose the technique of extended processing of cross-well seismic data for reflection imaging. Based on the analysis of the wave field and synthetic modeling, a graph for processing cross-well data is developed to separate the reflections in the presence of a boundary of a sharp change in the velocity of elastic waves. The migration of the reflected waves from the time scale to the depth is performed by solving a forward problem for each source-receiver pair. As a result, the position of the reflection points is calculated, after which all the traces are stacked based on the binning grid. The input information for performing migration and solving a forward problem is the velocity characteristic of the massif, which is calculated using traveltime tomography on direct body waves obtained from the same data set of cross-well survey and vertical seismic profiling. The resulting depth seismic section has a much higher resolution than that of vertical seismic profiling and ground-based shallow seismic studies. This opens up the opportunity of identifying different small natural or technogenic objects in the interwell space.