Purpose: Increase the vertical resolution of the seismic data. Theory: A matching filter is designed that shapes the seismic amplitude spectrum to resemble the amplitude spectrum of measured logs. In the general case, amplitudes at low frequencies are reduced while amplitudes at higher frequencies are enhanced. Detailed information that is inherent in the seismic signal becomes visible, while noise is not increased to unacceptable levels. Software: OpendTect + Seismic Spectral Bluing
Workflow:
Open the attribute set window, select attribute: Spectral Blueing, select input Data .
Press Analyze and Create ... to open the Spectral Blueing application.
Select Input Seismic and Well data, select well logs (right-click on the well) and time windows for seismic and wells. To load, press Load seismic and Reload wells, respectively.
Select Design controls and play with the parameters (increase the smoothing operator, toggle range and try reducing the max. frequency, toggle Auto Calc. and change low-cut and high-cut). Notice how the curves change interactively. Chose parameters that yield a smooth spectrum over the seismic frequency band.
Apply the Spectral Blueing attribute to the seismic data in batch: Processing - Create seismic output, or on-the-fly: right-click on the element in the tree (e.g. part of an inline).
Tips:
Sometimes low and high mono-frequency noise trails are observed in the spectral blued data. The frequencies of such noise trails correspond to the cut-off frequencies specified in the design window. To reduce these effects try changing the cut-offs. Look at the spectrum of the operator (the blue curve) that should be straight over the seismic bandwidth without lobes on the side.
Use the Chart Controller and Zoom options (View menu) to see all graphs simultaneously.
