Integration of Spectral Decomposition Using Fast Fourier Transform, Seismic Facies and Attributes Analysis in Delineating Complex Structural and Stratigraphic Features

Abstract

Spectral decomposition using fast Fourier transform was integrated with seismic facies and attribute analysis to delineate complex structural and stratigraphic features in the B field in the Niger Delta basin, Nigeria. The complex structural style and stratigraphic architecture of the Niger Delta basin combined with the need to increase the discovery of hydrocarbon accumulations demands the application of more nuanced seismic interpretation techniques in exploration. Conventional techniques are more suited for the discovery of structural traps. The methodology used in the work focuses on both structural and stratigraphic trapping elements. The objective of the study was to delineate complex structural and stratigraphic features within the B-field that can serve as viable hydrocarbon exploration targets. The methodology includes well facies analysis and correlation, reservoir identification and well-to-seismic tie, structural interpretation, seismic facies and attribute analysis, and spectral decomposition using fast Fourier transform. The B field lies within an extensional regime and the trapping is a simple faulted rollover anticline. Three stratigraphic intervals were identified from well analysis, corresponding to the freshwater sands of the Benin Formation, the paralic sequence of the Agbada Formation and the marine shales of the Akata Formation. Additionally, four reservoir intervals were identified and correlated. The structural style is dominated by a structure controlling basin-dipping boundary growth fault trending approximately east-west. There are other smaller faults that are synthetically linked to the boundary fault and also antithetic faults. Seismic facies analysis identified three dominant facies types, with the reservoir interval having more type II facies. Attribute analysis helped to characterize the reservoir intervals and highlighted the important heterogeneity of facies and fluid distribution within the reservoirs. Spectral decomposition revealed important channel features, with the channel system identified as braided.

Publication Info:

Author: Orji, O. , Egwuonwu, G.N. and Obiora, A.

Volume: 60

Issue: September

Published By: Journal of Mining and Geology Vol. 60(2) 2024. pp. 255 - 267 © Nigerian Mining and Geosciences Society (NMGS, 2024-09-01