Watch videos of Presentations from SEG 2017
Using Attributes to Interpret the Environment of Deposition - A Video Course. Taught by Kurt Marfurt, Rocky Roden, and ChingWen Chen
Dr. Kurt Marfurt and Dr. Tom Smith featured in the July edition of AOGR on Machine Learning and Multi-Attribute Analysis
Rocky Roden and Ching Wen Chen in May edition of First Break - Interpretation of DHI Characteristics using Machine Learning
Seismic interpretation and machine learning by Rocky Roden and Deborah Sacrey, GeoExPro, December 2016

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Phase Breaks

Attribute Description:  The Phase Breaks signal marks phase discontinuities by picking peaks from a difference signal that is constructed by subtracting the phase signal from the smoothed phase signal.  It extracts a peak at the -180-degree phase point of the real trace and creates a 3 sample spike to designate that location. The result reflects the discontinuities in the phase and is amplitude independent. For greater detail read “Banded Attributes Overview".

This is a display of amplitude a(t) and phase breaks. Notice how each phase break matches a trough in the amplitude display

This is a display of amplitude a(t) and phase breaks. Notice how each phase break matches a trough in the amplitude display

Interpretation Use:  This attribute may provide value by:

  • Providing improved “trough” interpretation
  • Showing boundaries of sequences and depositional environments
  • Showing discontinuities and faults
  • Making normal event interpretation easier as amplitude is removed

Recommended Colorbar:

Since the distribution of this data is all positive, and amplitudes reside in a 3 trace spike, a wraparound colorbar gives a trace-like view and highlights discontinuities.

Example Colorbar and amplitude spectrum

Example Colorbar and amplitude spectrum

Example:

Vertical display of Phase Breaks

Vertical display of Phase Breaks

Time slice of Phase Breaks

Time slice of Phase Breaks

Frequency Spectrum

Frequency Spectrum

Computation: Phase breaks is computed in several steps.  First, smooth phase is computed as

Phase Breaks - 06.png

where b(t) is a boxcar function with a length of T samples and height 1/T

Phase breaks are computed by convolving a 3-sample Hanning smoother han(t) with the Hilbert transform of the difference between the phase and the smoothed phase.

References:

  • Taner, M. T., 2001, Seismic attributes:  Canadian Society of Exploration Geophysicists Recorder, 26, no 7.
  • Tom Smith, Paradise Instantaneous Attributes, 2017, Paradise Help