Computer migration of oblique seismic reflection profiles

A reflecting interface with irregular shape is overlain by a material of constant velocity VT. Multifold reflection data are collected on a plane above the reflector and the reflector is imaged by first stacking then migrating the reflection data. There are three velocity functions encountered in this process: the measured stacking velocity VNMO; the true overburden velocity VT; and a profile migration velocity VM, which is required by present point‐imaging migration programs. Methods of determining VNMO and, subsequently, VT are well‐known. The determination of VM from VT, on the other hand, has not been previously discussed. By considering a line‐imaging migration process we find that VM depends not only on the true section velocity but also on certain geometrical factors which relate the profile direction to the structure. The relation between VM and VT is similar to, but should not be confused with, the known relation between VNMO and VT. The correct profile migration velocity is always equal to or gr...