METHOD OF PROCESSING SEISMIC DATA BY PROVIDING SURFACE OFFSET COMMON IMAGE GATHERS

摘要

The method processes input (DS,G[t]) including, for each of a plurality of shots at respective source locations, seismic traces recorded at a plurality of receiver locations. Offset-modulated data (D'S,G[t]) are also computed by multiplying the seismic data in each seismic trace by a horizontal offset between the source and receiver locations for said seismic trace. A depth migration process is applied (i) to the seismic data to obtain a first set of migrated data (MS[x,y,z]), and (ii) to the offset-modulated data to obtain a second set of migrated data (M'S[x,y,z]). For each shot, offset values (hS[x,y,z] ) are estimated and associated with respective subsurface positions, by a division process applied to the first and second sets of migrated data. A migrated value (Rx y[z,h]) for a depth z and an offset h in a surface offset common image gather (CIG) at a horizontal position x, y is a migrated value of the first set of migrated data associated with a subsurface position x, y, z for a shot such that the estimated offset value associated with that subsurface position is the offset h.