METHODS AND SYSTEMS TO SEPARATE WAVEFIELDS USING PRESSURE WAVEFIELD DATA

摘要

This disclosure is directed to wavefield separation methods and systems. In one aspect, methods and systems compute an approximate vertical particle velocity wavefield based on a measured pressure wavefield and knowledge of free-surface when the pressure wavefield was measured. The measured pressure wavefield is used to compute an approximate frozen free-surface profile. The approximate frozen free-surface profile and the measured pressure wavefield are used to compute an approximate vertical particle velocity wavefield. The approximate vertical particle velocity wavefield and measured pressure wavefield may be used to compute separate up-going and down-going pressure, or vertical particle velocity, wavefields.

主权项

1. A method comprising:
computing forward and backward extrapolated gathers based on a pressure wavefield gather for each trial depth of a series of trial depths, the pressure wavefield gather generated by receivers of a seismic data acquisition system located beneath a free-surface of a body of water; computing an approximate frozen free-surface profile of the free-surface based on the forward and backward extrapolated gathers; computing an approximate vertical particle velocity wavefield gather based on the pressure wavefield gather and the approximate frozen free-surface profile; and computing one of separate up-going and down-going vertical particle velocity wavefield gathers based on the pressure wavefield gather and the approximate vertical particle velocity wavefield gather.