Investigation of the common depth point method by means of synthetic seismograms

[摘要] In seismic reflection shooting, some of the traces correspond to relatively large angles of incidence, especially when the method of common depth point is used. In an effort to observe the effect of the angles of incidence on traces with common depth point, approximations of synthetic seismograms at oblique incidence with and without multiples were constructed. The theory of constructing a synthetic seismogram is briefly explained, under the assumption that S waves do not exist. After obtaining three approximations of synthetic seismograms for assumed shot point to geophone distances of 400, 800, and 1200 feet respectively, the effects of initial suppression, filter, and automatic gain control were simulated. The three synthetic seismograms so obtained were staked together to obtain a single seismogram for various comparisons. It is concluded that as the angles of incidence of the shot traces increase, so do the differences with respect to a trace shot at normal incidence. From the comparison of the stacked traces it is proved that the common depth point stacking process leads to a better definition of the character of the reflections, in comparison with the conventional process.

[发布机构] Rice University