Spectral Analysis and Filtering of Seismic Signals from Oil Exploration Activities in the Anambra Basin

The Anambra Basin in South East Nigeria has emerged as a frontier onshore exploration target following geological surveys indicating significant hydrocarbon potential, yet the mathematical processing of seismic reflection data from the basin requires sophisticated signal analysis methods adapted to the basin's complex geological stratigraphy. This study applies Fourier transform spectral analysis, bandpass filtering design, and deconvolution techniques to seismic reflection data acquired from a 2D seismic survey line crossing three prospect structures in the basin. Raw seismic traces are first analysed in the frequency domain to characterise the signal-to-noise ratio and dominant frequency content across depth intervals. Butterworth and Ormsby bandpass filters are designed to attenuate ground roll noise, high-frequency ambient interference, and low-frequency instrument drift while preserving the signal bandwidth of primary reflections. Spiking deconvolution using the Wiener filter is applied to collapse the seismic wavelet and improve temporal resolution of reflector identification. The processing sequence improves the signal-to-noise ratio of primary reflections by 14 decibels and enhances identification of stratigraphic targets at 2.2 to 2.8 seconds two-way travel time. Interpreted geological structures from the processed profiles correlate with published gravity anomaly data from the basin. Keywords: spectral analysis, seismic processing, Anambra Basin, Wiener filter, deconvolution.