Application of aeromagnetics as a basin depth discriminating tool prior to seismic exploration: A case study of Central Niger Delta, Nigeria

Abstract

The importance of aeromagnetic as a basin depth discriminating tool is the  emphasis in this study. Eight sheets of aeromagnetic total field intensity maps on a scale of 1:100,000 were analysed and the depth to magnetic basement compared with available drilled well data. The data was processed, filtered and transformed to other grids using either Oasis Montaj and USGS potential field software with their associated extension packages. Anomaly Separation, Spectral Analysis, Euler Deconvolution, Horizontal Gradient Magnitude were done using Oasis montaj and U.S.G.S softwares .The results of spectral analysis, Euler Deconvolution and  horizontal gradient depth maps generated clearly indicates that the well bottom (well B) depth of 3.234km compared with the different thematic magnetic basement depth from spectral 4.2km, Euler 6.421km, and HGM 4.0kmis effective in basement depth discrimination. The result show a unique closeness when compared between already drilled depth with interpreted magnetic depth results. This indicate that the method can be reliable as a basin depth determining tool in virgin sedimentary basins prior to seismic explorations.

Keywords: Aeromagnetic, Euler Deconvolution, Spectral analysis, Horizontal gradient magnitude, Exploration.