Abstract
We present a case study with regard to multiple contamination of seismic data in post-stack 3D seismic data in the North Kuwait Gotnia subbasin, which holds very good hydrocarbon potential within Pre-Cretaceous reservoirs but faces considerable challenge in reservoir characterization because of its multiple contamination. This study attempted to focus mainly on the Pre-Cretaceous carbonate reservoir around the KM structure.
The main challenge is to deal with interference of 5th or 6th order peg-leg multiples with primary signals at the reservoir level. Peg-leg multiples are instances of short-path, multiple reflected seismic energy that can directly impact the seismic inversion results, facies mapping, structural interpretation, and hence depth prediction.
The improved approach to multiple attenuation could be demonstrated by a pilot processing using the following techniques on select locations.
The new technique delineates a spatial an area which may be contaminated with multiples in post-stack 3D seismic data. First step tool for interpreter.
Key elements gained from this method to implement multiple mitigation measures, which can reduce the multiple-contamination effect in post-stack data are:
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Identifying spatial area of contamination by observation by horizon flattening.
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Nature of amplitude contamination over structurally favourable locations.
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The interference may indicate the nature of multiple contamination. This method is subject to testing.
A new approach to identifying and interpreting multiple contaminated primaries in full-stack seismic data provided a better interpretation of data for the North Kuwait Gotnia sub-basin. It revealed need for more multiple modeling and vertical seismic profiling (VSP) in all wells. However, it also provides a methodology for reprocessing for all available 3D seismic data through multiple mitigation that can improve seismic inversion, reinterpretation, geomodeling on newly processed 3D seismic data
