Plane-wave migration in tilted coordinates

Conclusion

Plane-wave migration in tilted coordinates makes the extrapolation direction close to the actual propagation direction in the subsurface by assigning a well-chosen tilted coordinate system for each plane-wave source. One-way wave equations in tilted coordinates are exactly the same as those in vertical Cartesian coordinates, therefore we can still use the accurate one-way extrapolator methods developed for vertical Cartesian coordinates in last two decades to reduce the sensitivity to the coordinates. Plane-wave migration in tilted coordinates is much cheaper than reverse-time migration, but it can handle waves that illuminate steeply dipping reflectors and overhanging flanks, such as high-angle energy and overturned waves, which are challenging to image with conventional one-way downward continuation migration. Examples show that plane-wave migration in tilted coordinates is a good tool for delineation of complex salt bodies.