Source Amplitude Solution

Source Amplitude Solution 3D survey, dual source

Early QC checks

compute RMS amplitude statistics for each sail line

compute RMS amplitude statistics on shot and channel basis

analyse frequency spectra of selected shots

Amplitude of the two sources seen to vary considerably across the survey

One source consistently stronger than the other

Differences in frequency content apparent between the two sources Signature Deconvolution

Source wavelet matched to a user-defined wavelet

Deconvolution performed separately for each gun and matched to a common wavelet

No need to determine which gun has correct spectrum

Deconvolution filters derived for each shot from running average across 50 field records at a time

Deconvolution filters applied on shot-by-shot basis

Amplitude and frequency discrepancy between sources is significantly reduced by the application of signature deconvolution

Equalisation of the amplitudes is clearly visible on RMS displays, shot plots and near traces

Survey-wide variation in source amplitude is eliminated

Surface Consistent Scaling Amplitude variations will exist within data volumes on many levels

Channel, shot, gun, cable, line, receiver etc

The measured amplitude responses in the data are modelled using a series of such terms (also including CMP & offset terms)

The model is estimated in a least squares sense, with the terms being computed iteratively in a user specified order.

Corrections can be computed on individual lines or on a number of lines simultaneously.

Line to Line Corrections (Common Offsets)

Line to line amplitude variations can be effectively & safely removed after fold normalisation.

Amplitudes extracted on common time slices for each common offset.

Median amplitude responses analysed and corrections applied to correct raw amplitudes to these median values.

Time dependent scalars (ie filtering can be easily controlled if necessary through target horizons)