Common-reflection-point stacking in laterally inhomogeneous media

An important seismic reflection-imaging process which is widely applied in practice in an approximate form is the simulation of a zero-offset (ZO) sec tion from a set of common-offset (CO) sections. Rather than using the famil iar common-midpoint (CMP) stack (which suffers from reflection-point disper sal when the reflectors are dipping), the aim now increasingly is to perfor m an accurate common-reflection-point (CRP) stack. In the latter case, all primary CO reflections used for the simulation of a particular ZO reflectio n are expected to have a common reflection point. A CRP stack can be perfor med with a macro-velocity model or with the near-surface velocity only. The fundamental CRP reflection and stacking trajectories involved in both of t hese CRP stacking techniques are inherently related. The aims of this paper are (a) to give some simple analytic formulae for these trajectories for t he constant-velocity case and (b) to describe two CRP stacking methods for 2D laterally inhomogeneous media that make use of the formulae.