Prospectivity of Passive Margin Turbidite Fans: Implications of an Unconventional Resource, Hydrocarbon Storage Capacity, and Tectonic Evolution, Rio Del Rey Basin, Cameroon

Abstract

The Rio del Rey Basin, situated at the easternmost extension of the Niger Delta in the Gulf of Guinea, remains one of the least explored deep-water provinces, despite its proven petroleum system and structural affinity with the prolific neighboring basins. This study integrates well-log interpretation, petrophysical evaluation, and seismic stratigraphy to assess the depositional architecture and hydrocarbon prospectivity of slope-to-basin-floor turbidite systems within two exploratory wells (Idabato and Ifiari East) and regional 2D seismic profiles. Petrophysical analysis using Interactive Petrophysics software indicates that middle Miocene sand-rich intervals exhibit favorable reservoir properties, with effective porosity ranging from 20% to 35% and permeability locally exceeding 400 mD. Total organic carbon (TOC) values derived from log-based ΔlogR modeling range between 1.6 and 8.4 wt%, confirming the presence of organic-rich shales capable of sourcing hydrocarbons. Cross-plot analyses (neutron–density and sonic–density) reveal three dominant lithofacies: clean turbiditic sands, shaly sands, and marine shales organized into low-stand and high-stand system tracts within fault-bounded mini-basins. Seismic interpretation identifies growth faults, rollover anticlines, and shale diapirs as key structural controls on sand distribution and trapping geometry. These findings confirm the presence of a fully functional petroleum system comprising source, reservoir, and seal elements within deep-water turbidite complexes. Exploration potential remains high in stratigraphic traps at channel-lobe transitions and in structural closures adjacent to shale diapirs. This study provides a predictive framework for hydrocarbon exploration in the Rio del Rey Basin and analogous Atlantic passive margins globally.