Accurate and Efficient Absorption Compensation Pre-imaging

Inverse Q compensation is most accurately performed when included in the imaging step. However, this is a computationally expensive process, therefore methods which can perform the Q compensation as part of the pre-migration data conditioning are used regularly. In a deep-water environment, in particular, the application of Q compensation needs to take into account that no dispersion occurs in the water. Methods which correctly handle the water layer under the straight ray assumption like in Xia provide more optimal results. To provide a more accurate, yet simple compensation not limited by the straight ray assumption, we propose a new method using a combination of two straight ray approximation methods.

In this study, we present a 3D application of inverse Q filtering prior to imaging based on the inverse Q application method developed by Xia and a new straight ray Q-effective method with its corresponding scheme for spatial averaging. We demonstrate that new approach is more accurate for far offsets, as well as in the presence of a 3D spatially variant Q model. The comparison between this method and inverse Q application within Kirchhoff Pre-Stack Depth Migration validates the advantage of using this method for accurate imaging supra-salt and subsalt events.