Curie Point Depth (CPD) Investigation Of Offshore Niger Delta Using High Resolution Aeromagnetic Data

Abstract

Offshore Niger Delta, Nigeria, is known to be a hub for hydrocarbon exploration within the West Africa region and the world in general. The geologic settings within the Niger Delta province have a proven potential to assist in oil and gas exploration. However, much of the offshore provinces potential remains unknown with respect to the temperature differences using aeromagnetic data. In the present research, high resolution aeromagnetic data covering longitude 4°30ⁱ E - 5° E and latitude 3°30ⁱN - 4°30N with an approximate area of about 6050 km² was used to estimate the Curie Point Depth (CPD) of the study area. For this aim to be realizable, regional-residual was undertaken on the Total Magnetic Intensity (TMI) data. This art gave rise to the regional and the residual maps. The residual map was then after divided into thirty five overlapping spectral grids. Spectral analysis was performed on each of the grids and this decomposed each grid into its energy and frequency segments. The results show three depth models, namely the depth due to the deeply seated sources or the centroid depth, D_c, depth due to the shallow magnetic sources, D_t and the depth at which minerals lose their ferromagnetic properties or the basal depth, D_b. However, D_c varies from - 9950 m to - 35294.12 m but with a true or average depth value of - 9751.75 m while D_t lies between -1250 m and -3684.21 but with a true depth of - 2000 m. Similarly, the basal depth ranges from -9950 m to -35294.12 m. This study therefore suggests that at a depth of - 9950 m and beyond ferromagnetic minerals turn into a paramagnetic one within the area of study.