Advanced seismic attributes applied on resolution-enhanced 2D seismic data for BSR mapping offshore Makran, Pakistan

Area of Science:

• Geophysics
• Marine Geology
• Petroleum Geoscience

Background:

• Identifying gas hydrates and bottom simulating reflectors (BSRs) in seismic data is challenging due to signal limitations.
• Seismic attributes have proven effective in recognizing hydrocarbon reservoirs and can aid BSR interpretation.

Purpose of the Study:

• To test and apply an integrated seismic attribute workflow for mapping BSRs.
• To qualitatively interpret BSR-related anomalies, including potential free-gas indicators.
• To improve the identification of gas hydrate systems in the Makran Accretionary Wedge.

Main Methods:

• Applied structure-oriented data conditioning (dip-steered median filtering) to re-processed seismic data.
• Extracted amplitude attributes (Pseudo-Relief, Square-Root-of-Energy) and performed frequency decomposition (FFT, CWT).
• Utilized RGB color blending for visual identification of BSR-related anomalies.

Main Results:

• Pseudo-Relief highlighted the geometric expression and curvature of BSRs and anomalies.
• Square-Root-of-Energy revealed spatial variations in reflection energy across BSR intervals.
• Frequency decomposition (40 and 60 Hz) showed enhanced amplitude for BSRs and underlying reflections. RGB blending aided anomaly zone identification.

Conclusions:

• The integrated seismic attribute workflow effectively aids in mapping BSRs and interpreting associated anomalies.
• This method enhances the visualization and identification of potential gas hydrate and free-gas systems.
• Qualitative interpretations are supported by attribute analysis in the absence of calibration data.