dGB Earth Sciences


Spectral decomposition and RGB(A) blending is not only useful for studying sub-seismic resolution stratigraphic features, but can be a great asset to highlight potential bright (spot) amplitude anomalies.

As you can see in this video, there is a strong amplitude observed at around 1.8s.To aid in describing such an anomaly, we mapped it using OpendTect inversion + tracker. This tracker combines amplitude tracking and tracking from seismic dips. OpendTect’s attribute engine boasts four different attributes for spectral decomposition. The “Spectral Decomposition” attribute supports short-window FFT (Fast Fourier Transform) and CWT (Continuous Wavelet Transform) algorithms.

The user computes a range of components over the full seismic bandwidth. From this range three iso-frequencies are selected. The lowest frequency is displayed in the red, the middle frequency in the green and the highest frequency in the blue.

In the example shown in this movie, 3D seismic volume from Taranaki Basin, a color blended volume combines 14, 28, and 42 Hz components in the red, green and blue respectively added to the mapped horizon. The RGB result shows nicely the extension of a very strong amplitude anomaly.