Compensation of Absorption Effects in Seismic Data

Abstract

The frequency content of seismic data is changing with propagation depth due to intrinsic absorption. This implies that the higher frequencies are highly attenuated, thus leading to a loss in resolution of the seismic image. In addition, absorption anomalies, for example, caused by gas sands, will further dim the seismic reconstruction. The absorptive property of a medium can be described by a quality factor Q, which determines the energy decay and a velocity dispersion relationship. The quality factor and the velocity govern the propagation of seismic energy in the earth. It is possible to correct for such absorption effects by employing so-called inverse Q-filtering (IQF). This is a filtering technique that tries to restore the loss of the higher frequencies due to propagation. Newer developments within IQF can be regarded as a migration type of algorithm, and such classes of techniques are studied in this thesis.