Amplitude Compensation

Accurate space- and time-variant inverse-Q filtering

VariQ is the WesternGeco approach to the derivation of absorption (effective Q) fields and the application of time- and space-variant inverse-Q filters for absorption compensation. Energy absorption and velocity dispersion effects often vary both horizontally and vertically in the subsurface, creating complicated Q fields.

Conventional techniques recognize these fluctuations, but often leave residual amplitude and phase errors. In addition, many techniques are forced to make the limiting assumption that the seismic wavelet exhibits either a constant or zero phase angle.

VariQ estimates and applies an absorption compensation without any residual amplitude or phase errors, and with no restrictions on field variability. It aids interpretation, and is a key element where AVO and reservoir characterization objectives demand temporal and lateral wavelet consistency. The derived Q field can also be incorporated as an attribute in seismically derived Rock Property Calibration.