Machine learning-supported seismic stratigraphy of the Paleozoic Nubia Formation (SW Gulf of Suez-rift): Implications for paleoenvironment−petroleum geology of a lacustrine-fan delta

Abstract

Steeply dipping prograding fan deltas possess high reservoir quality facies that could be excellent targets while exploring for hydrocarbons. Due to their complex stacking nature, and limited examples, delineating their architectural elements is still challenging. In this paper we mainly performed sedimentary facies analysis; applying various disciplines e.g. sequence stratigraphy, seismic stratigraphy, GR-log motifs, and seismic waveform segmentation; so as to adequately depict the reservoir heterogeneity and quality of the Paleozoic Nubia clastics in West Esh El Mallaha Concession (southwest Gulf of Suez rift). Organic maturity prediction, to confirm the hydrocarbon charging from source units to reservoir intervals, was also of most importance in this study. Accordingly, 1D basin model was established to define the past geologic events; subsidence, and thermal maturity; and their controls on sedimentary basin evolution and associated petroleum potential. We utilized several key-information scales; e.g. wireline logs, and seismic profiles. Linking different disciplines applied in this study points to a successful integrated reservoir characterization workflow capable of unfolding ancient environments and the associated hydrocarbon potential. The results show that Nubia Formation was built during the lowstand−transgressive phase of a 3rd order depositional sequence. It encompasses fluvio-lacustrine system with eight sedimentary facies associations; form source to sink. Fluvial channels and mouth bars, settled in subaerial and subaqueous settings respectively, represent the most significant reservoir facies in the area. Given best hydrocarbon-reservoir quality, the deltaic mouth bars ought to attract attention of further oilfield development plans and be considered while investigating similar settings.