Enhanced Prestack Data
The fundamental geophysics behind UniQ
The Land Q-Technology methodology to deal with noise involves decomposing the orthogonal acquisition geometry into cross spreads. Each point-receiver cross-spread provides a single-fold subset of the continuous wavefield. Digital processing is applied to this finely-sampled dataset to attenuate noise and correct for signal perturbations.
The Land Q-Technology methodology to deal with noise is as follows:
- Decompose the orthogonal acquisition geometry into cross spreads, spatially repeated.
- UniQ cross spreads provide single-fold subsets of the continuous wavefield.
- Uncommitted, array-less recording allows a full data processing solution.
The inset figure shows the FKK spatial antialias filter response for an example areal geophone array (top) and for a DGF digital spatial antialias filter used with UniQ.
An ideal spatial antialias filter would have a flat response within the spatial filter pass-band and complete rejection outside it. The ideal filter response would also be azimuthally isotropic; i.e., the array response is the same for energy arriving from all angles.
The antialias filter performance for conventional data acquisition is typically achieved by the convolution of source and receiver arrays, with some imperfect and azimuthally variable level of noise rejection in the filter stop-band and an imperfect (non-flat) response in the pass-band. All remnant energy in the stop-band will be aliased into the pass-band during acquisition and appear as noise on the seismic trace.
The Q-Technology acquisition technique allows the application of optimal digital spatial antialias filters designed using the alternating projections onto convex sets (APOCS) filter design technique.
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