Green's theorem based onshore preprocessing - a reduced data requirement assuming a vacuum/earth model for the air/earth interface and the evaluation of the usefulness of that assumption

摘要

The elastic Green's theorem wave separation method can effectively reduce ground roll and ghosts in land data, and most importantly, without harming reflection data. Both tractions and multicomponent displacements are assumed in the original elastic Green's theorem method (Wu and Weglein, 2015a). However, it is not easy to measure tractions directly. In order to reduce the requirement of traction, this paper simplifies the algorithm assuming that the acquisition is on a vacuum/earth surface. The new formula requires the traction at only the source point rather than all the points along the measurement surface. The reason is that traction is zero everywhere except the place where the source is located. Synthetic tests show: (1) successful processing results for data that are generated assuming a vacuum/earth boundary, and (2) very useful results when the data are generated from a more realistic air/earth model.