Topography and near-surface heterogeneities lead to traveltime perturbations in surface land-seismic experiments. Usually, these perturbations are estimated and removed prior to further processing of the data. A common technique to estimate these perturbations is the delay-time method. We have developed the “modified delay-time method,” wherein we isolate the arrival times of the virtual refraction and estimate receiver-side delay times. The virtual refraction is a spurious arrival found in wavefields estimated by seismic interferometry. The new method removes the source term from the delay-time equation, is more robust in the presence of noise, and extends the lateral aperture compared to the conventional delay-time method. We tested this in an elastic 2D numerical example, where we estimated the receiver delay- times above a horizontal refractor. Taking advantage of reciprocity of the wave equation and rearranging the common shot gathers into common receiver gathers, isolated source delay times could also be obtained.
This document was originally published in Geophysics by the Society of Exploration Geophysicists. Copyright restrictions may apply. doi: 10.1190/geo2012-0111.1
Mikesell, T. Dylan; van Wijk, Kasper; Ruigrok, Elmer; Lamb, Andrew; and Blum, Thomas E.. (2012). "A Modified Delay-Time Method for Statics Estimation with the Virtual Refraction". Geophysics, 77(6), A29-A33.