Seismic Processing Enhancement and Attribute Analysis of the Early Jurassic Navajo Sandstone – Uinta Basin, Utah

Date

2016-12

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Abstract

Adding innovative techniques including five-dimensional interpolation, wavelet packet denoising, and bandwidth extension to a traditional seismic processing flow applied to a 3D seismic survey in the Uinta Basin improved signal-to-noise ratio, seismic resolution and attribute calculation of the thin bedded Jurassic Navajo sandstone (30-100 ft.). With five-dimensional interpolation, traces were filled in at places where acquisition restraints led to undersampling. Applying a moderate wavelet packet denoising removed a large portion of the random noise. This aided in velocity analysis for migration. A second round of denoising was run post migration to remove most remaining residual noise. Traditional spectral enhancement techniques resolved the base of the sandstone over a large portion of the survey. Bandwidth extension provided enhanced vertical resolution and lateral continuity better than traditional spectral enhancement techniques. Seismic attributes were integrated with log control to map the structural and stratigraphic nature to a degree not previously achievable on conventional data. Seismic coherence provided an in depth fault map for the Navajo sandstone and indicated the Navajo is laterally continuous (i.e., not truncated). A combination of spectral decomposition with peak attributes and well log control highlighted stratigraphic thinning and enabled mapping of changes in interval thickness. Due to resolution constraints, thin intervals are mapped with high iso-frequencies where the base falls below resolution and the response is from the resolved Navajo base. It was observed that wells producing from thin intervals experienced a decrease in well performance while wells that produce from the seismically thicker Navajo experienced an increase in overall performance.

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Keywords

Navajo, Uinta Basin, Spectral decomposition, Thinning

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