Description and interpretation of fault-related sedimentation and controls on shelf-edge deltas: implication on sand transportation to the basin floor in parts of Eastern Niger Delta

Abstract

An integrated structural and stratigraphic analysis of a regional dataset from Eastern Niger Delta was undertaken with the objective of improving the present understanding of the structural development, seismic reflection geometries and implication on sand transportation and deposition within the shelf-edge and farther into the basin floor. Well log correlations were carried out using third-order sequence stratigraphy. Fault dynamics and evolution was interpreted with the aid of seismic transect sections, growth fault indexes and dip-extracted semblance slices. Lithofacies and paleobathymetric data were utilized to create gross depositional environment maps for the various sequences from inner-shelf to upper slope environment. The fault dynamics and evolution analysis of co-planar faults shows that older co-planar faults are associated with more accommodation space and depocentres than relatively younger faults. Conceptual subsurface models from this study shows that there is an increase in sand thickness in the proximal part of the sequence associated with precursor (older) faults, while towards the distal part, it reduces. There is also a relative decrease in sand thickness in the proximal part of the sequence associated with younger initiated faults, while towards the distal part, it increases in sand thickness. This study shows that at the shelf-edge, the thickest sand is of the lowstand system tract and the possibility of transporting sands into the basin is more associated with younger co-planar faults with small accommodation space at the shelf-edge, while the precursor older faults retain majority of sand deposits within its subsidence/depocentre axis.

Reservoir and sequence stratigraphic analysis using subsurface data

“…The identified faults are characteristic of the Niger Delta Basin and have appreciable throw which can serve as a potential pathway for hydrocarbon (e.g., Corredor et al, 2005;Ahaneku et al, 2016;Anomneze et al, 2020). The anticlines can also possess multiple pay horizons, which are major parts of most giant oil fields (Ajakaiye and Bally, Ahaneku et al, 2016).…”

An integrated source rock potential, sequence stratigraphy, and petroleum geology of (Agbada-Akata) sediment succession, Niger delta: application of well logs aided by 3D seismic and basin modeling

“…The Niger delta is an extensional basin rifted from the Late Jurassic to the Late Cretaceous and is considered one of the basins formed due to the failing arm of the triple junction. The extensional force created a system of trenches and ridges in the Atlantic Ocean and troughs on the western margin of Africa (Tuttle et al 1999;Whiteman 2012;Anomneze et al 2020). The Niger delta is situated between the Benue trough and the Atlantic Ocean (Corredor et al, 2005).…”