AAPG Middle East Region Geoscience Technology Workshop

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Tectonics of the Northern Red Sea and Implications for Assessing Exploration Risk

Abstract

The Red Sea is an evolving rift basin with its northern part still undergoing continental lithosphere extension while its central and southern parts have already broken up and entered seafloor spreading mode. The basin offers excellent analogues to improve our knowledge about passive continental margin evolution, such as the conjugate central South Atlantic. Despite its potential as a powerful analogue, the kinematic history, lithosphere, and basin infill dynamics are poorly understood, as is its potential hydrocarbon prospectivity. A number of wells, targeting post-, syn- and pre-rift plays in the northern Red Sea have failed to deliver economic value, despite the northernmost extent of the Red Sea rift system, the Gulf of Suez hosting a number of significant hydrocarbon fields. We are presenting a revised quantitative plate kinematic model of the Red Sea evolution which is based on new 2D seismic and potential field data. Our new deforming plate model treats the opening of the Red Sea as a two-phased system, linked to continental extension in the Gulf of Suez and later, along the Dead Sea/Gulf of Aqaba transform. The total extension across the system amounts to approximately 140 km, partitioned in two phases over about 30 Million years – an earlier one starting around early Oligocene times (31-30 Ma) which initiated the Red Sea as intracontinental rift and a later one commencing around Mid-Miocene times (22-20 Ma) linked to the Dead Sea transform becoming active. In line with existing publications, we suggest that the northern Red Sea has entered a phase of crustal hyperextension, possibly shortly before continental lithosphere breakup and the onset of seafloor spreading. We integrate the observations and plate kinematic models with simple forward models of lithosphere deformation using Badley’s Stretch software to assess the evolution of crustal stretching, flexural uplift and erosion on hydrocarbon prospectivity and exploration risk for pre-, syn- and post-rift plays. Our work allows to link the two phases of extension to structuration and rift styles in the northern part of the Red Sea, which we assume have implications for prospectivity at different play levels.