A Cepstral Technique for Unmasking Vital Sub-Seismic Stratigraphic Details Embedded in Dense 3D Seismic Data from Niger Delta

Abstract

Seismic visibility is enhanced through the change of the seismic data outlook from the standard amplitude measurement to a new domain in order separate fact from artifact in seismic processing and interpretation. General seismic data interpretation involves direct fault and horizon mapping, sequence stratigraphy and seismic modeling to produce structural, stratigraphic and reservoir maps for the delineation, exploration and production of hydrocarbon in oil fields. These methods operate on stacked and migrated data and without adequate calibration. Besides, final stacks are inadequately displayed, processing is coarse and in time domain. Actual hydrocarbon entrapments are rarely detailed well enough to permit reliable location of wells from these studies alone owing to noise. This paper presents the results of the application of Cepstral transform (CT) in the interpretation of the 3D seismic data in the Niger Delta. The aim of the study was to develop a robust technique for mapping subtle stratigraphic units which are usually masked during normal data interpretation using Cepstral algorithm. The Cepstrum is the Fourier transform of the log of the spectrum of the data. The transform filters the field data recorded in time domain, and recovers lost sub-seismic geologic information in quefrency domain. Cepstral domain analysis separates source and transmission path effects. The algorithm is based on fast Fourier transform technique and was developed within Matlab software. The results of the Cepstral decomposition yielded gamnitude, saphe and quefrency maps of the reservoir and revealed sub-seismic faults, differences in lithology and better reservoir delineation and delimitation.