Biostratigraphy and sequence stratigraphy of the deep offshore Niger Delta and implications for future hydrocarbon exploration in the Paleogene sequences

Abstract

The Niger Delta Deep Offshore Basin has been the latest frontier within the Niger Delta for hydrocarbon exploration and production activities. Until the onset of drilling activities in the early nineteen nineties, little was known about the biostratigraphy of this frontier setting. Thus, uncertainties existed in the ages ascribed to the various stratigraphic sequences. Presently, several wells have been drilled in the Deep Offshore Niger Delta and a three-pronged biostratigraphic data and some sequence stratigraphic interpretations have become available. We integrated biostratigraphic data comprising palynological, foraminiferal, and calcareous nannoplankton zonation and biofacies, wireline log information and regional-3D seismic data, with simple basic sequence stratigraphic analysis for a detailed well correlation, regional mapping of hydrocarbon-bearing intervals, and evaluation of the thicknesses of promising stratigraphic intervals. Results show a significant effect on not only the earlier conceptualized age of the deepest prospective reservoirs, but also the ages of possible source rocks in the Paleogene of the Niger Delta Offshore sequence. This finding will help in the realistic assumptions of source rock characterization, charge modeling/prediction, and the stratigraphic thicknesses of the offshore sequences and their reservoirs. This paper examines the specific derivable age interpretations from the integration of at least six wells, biostratigraphic data with seismic and the implications of these interpretations for hydrocarbon prospectivity of the Paleogene sequences. Furthermore, this paper documents the biostratigraphy work done in the area, in all the structural belts where drilling has occurred including the deepest well drilled in the Deep Offshore Niger Delta, Bosi-006. The results of this study have a critical impact on the current regional geological understanding of the Deep Offshore Niger Delta.

Lithofacies, Depofacies and Reservoir Characteristics of Well TMG-08, Opolo Field, Niger Delta

“…Large amount of data from several thousands of drilled wells have led to a considerable understanding of the stratigraphy and regional geology of the delta. Information have been published on petroleum sedimentology by various workers including: (Short andStauble, 1967, Weber andDaukoru 1975) and biostratigraphy by (Adegoke, et al 1971, Seiglie, et al 1982, Ozumba 1995, Adeniran, 1997, Umoh and Fasina, 2019 from the western Niger Delta. The stratigraphy, Sedimentology, structural configuration and paleo environment during which the reservoir rocks accumulated have been studied by various workers (Short and Stauble, 1967;Weber, 1971;Weber and Daukoru, 1975;Evamy et al, 1978;Rider, 2002;Selley, 1978, Amigun, et al, 2012, Emujakporue, 2016Victor et al, 2019, Aigbogun andMujakperuo, 2020).…”