Attribute Description: Envelope Slope (Time Derivative of the Envelope) shows the variation of the energy of the reflected events. The derivative computed at the onset of the events shows absorption effects. A slower rise indicates larger absorption effects. Events with a sharp relative rise also imply a wider bandwidth, hence fewer absorption effects. This attribute is also a physical attribute and it can be used to detect possible fracturing and absorption effects.
Interpretation Use: This attribute may provide value because:
- Sharpness of the rise time relates to absorption in an inversely proportional manner
- It is affected by the slope, rather than envelope magnitude
- Lateral variation shows discontinuities,
- It is used in the computation of group propagation direction. When compared with phase propagation direction, it may indicate dispersive waves.
Since the distribution of this data is Gaussian in nature, with high values at the extremes, a standard seismic colorbar can work.
In this example, we are using a white-black colorbar where white and black highlight the extreme values in the histogram and the intermediate values are displayed in a gray tone.
A specially designed time domain filter is used to perform the differentiation.
Where * denotes convolution, and diff(t) is the differentiation operator
- Chopra, S. and K. J. Marfurt, 2007, Seismic attributes for prospect identification and reservoir characterization: Society of Exploration Geophysicists, Geophysical Developments #11.
- Taner, M. T., 2001, Seismic attributes: Canadian Society of Exploration Geophysicists Recorder, 26, no 7.