Sequence stratigraphic and petrophysical controls on the oil-reservoirs architecture: A case study from the Cretaceous meqasequence, Gulf of Suez region, Egypt

Abstract

This research aims to perform a comprehensive examination encompassing sequence stratigraphy and petrophysical assessment of the Cretaceous meqasequence along the Gulf of Suez region. Through an investigation of eight wells, spanning both offshore and onshore fields in the Gulf of Suez Basin, the sequence stratigraphic analysis reveals a division of the Cretaceous meqasequence into two distinct depositional sequences: Early Cretaceous (SQ-1) and Late Cretaceous megasequence. The Early Cretaceous megasequence comprises the Nubia Sandstones, while the Late Cretaceous megasequence includes the siliciclastic/carbonate sediments found within the Raha, Abu Qada, Wata, and Matulla Formations (SQ-2, SQ-3, and SQ-4). The distribution of the Cretaceous megasequences across the study area highlights a significant variation in thickness from the onshore to the offshore regions of the Gulf of Suez. This variation is primarily attributed to tectonic forces that governed both the deposition and erosion of sediments over time. The lowstand systems tracts (LSTs) and highstand systems tracts (HSTs) within both Cretaceous megasequences are characterized by sufficient sand content, making them favorable reservoirs.

Conversely, the transgressive systems tracts (TSTs) are identified as potential reservoir rocks. The analysis of petrophysical properties across different Cretaceous reservoirs reveals that the Early Cretaceous fluvial megasequence exhibits superior reservoir qualities compared to its Late Cretaceous counterpart. However, the Late Cretaceous megasequence comprises reservoirs with multiple levels and diverse petrophysical characteristics. The study offers valuable insights into how petrophysical properties and sequence stratigraphy influence Cretaceous reservoir architecture. Examining the depositional environments and petrophysical evaluation enhances our understanding of reservoir quality and distribution. Furthermore, it guides future exploration activities in the mixed siliciclastic and carbonate multi-level intervals of the Gulf of Suez and nearby basins, aiding in identifying potential hydrocarbon zones and optimizing drilling strategies.