The Plus-Minus time analysis (PMT) method was developed to solve the time delays on reflection seismic data caused by low velocity near-surface deposits. The PMT method includes a Plus time analysis for depth analysis and a Minus time analysis for velocity determination. The PMT method was tested with a synthetic dataset and provided a reliable near-surface model.
A refraction analysis involving a three-componreplent 2D seismic line from the Blackfoot area was completed. S- wave refractions were identified on the radial component and were used to establish an S- wave near-surface model, while P- wave refractions were used to build the P- wave model. According to the P-S reflection raypath geometry, the shot static corrections were computed from the P- wave model and the receiver static corrections from the S- wave model and were applied to the radial component data to produce stacked sections. Improvements in reflector continuity and energy focus were found.
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