Abstract Recent work by a multi-disciplinary team has led to a significantly better understanding of the prospectivity of the North Red Sea. New regional biostratigraphic and environmental analysis from north to south through the Gulf of Suez and into the Red Sea have placed the Nubian sequences into a regional chronostratigraphic framework. The Nubian Upper Cretaceous pre-rift sandstones are observed in the field on both the Egyptian and Saudi Arabian side of the North Red Sea. This regionally extensive sequence was deposited in a continental to shallow marine setting fringing the Mesozoic Tethys Ocean, which lay further north. Extensive onshore fieldwork and mapping of sediment input points, fault orientations and fault linkages have helped to develop an understanding of the expected controls on syn-rift sandstone and carbonate deposition offshore. Thick halite with interbedded evaporite and clastics in the Late Miocene sequences of the Red Sea pose seismic imaging challenges. Recent reprocessing and newly acquired seismic data have produced a step change improvement in imaging of the prospective pre-rift section. Petroleum systems modelling incorporating new information on rift timing and crustal thinning as well as onshore core analysis for source rock properties and temperature variation through time indicates that oil expulsion occurs in the inboard section of North Red Sea – Block 1. This is supported by hydrocarbon shows in the drilled offshore wells which can be typed to pre-rift source rocks from stable isotope and biomarker data. All the key elements of the Gulf of Suez petroleum system exist in the North Red Sea. An integrated exploration approach has enabled prospective areas in the North Red Sea – Block 1 to be high-graded for drilling in early 2011.

Abstract 3D visualizations of modern, high-resolution seismic data have provided valuable insights into the finite geometries and spatial extent of extensional fault systems, but their evolution in time is poorly understood. Scaled 3D analogue models of rift basin evolution provide kinematic templates for understanding the 4D evolution of extensional fault systems. This paper reviews the development of extensional fault systems in analogue models of orthogonal, oblique and offset rifts. In orthogonal and oblique models, stretching above a zone of ductile deformation at the base of the model initially produced segmented rift border faults whose orientations were strongly controlled by the underlying baseplate configuration. In contrast, the intra-rift faults generally initiated at high angles to the extension direction. With increased extension both the rift border faults and the intra-rift faults propagated along strike, first producing segmented fault systems separated by relay ramps, which, with increased extension, became breached as fault linkage occurred. Kinks in the fault traces indicate linkage points. Within the models, asymmetric intra-rift sub-basins were formed where the extensional fault arrays had a dominant dip polarity. Intra-basin accommodation zones, separating individual sub-basins along the rift axis, were formed by interlocking oppositely dipping fault systems. Offset oblique rift models, formed above a zone of ductile stretching with basement offsets, generated intra-basin accommodation zones whose orientation was controlled by the underlying basement fabric. The results of the analogue models can be directly compared with fault systems in the Northern Ethiopian rift system, with the accommodation zones in the Gulf of Suez, Egypt, with extensional fault arrays in Canyonlands, Utah, and with rift fault systems in the Gulf of Thailand and the southern North Sea.

Abstract Using observations from the extensional basin setting in Vietnam, conceptual models were developed to simulate and analyse fracture systems typical of crystalline basement in such structural settings. Information from field observations, seismic surveys and three-dimensional (3-D) structural modelling were integrated and used to build geologically realistic 3-D fracture networks. A major advantage of the method used in this study is that it allows a better understanding of the apparently chaotic fracture networks characteristic of such rocks, and of the processes responsible for fracturing. Several fracture generating processes are discussed and modelled, with emphasis on tectonic fractures and the relation to structural modelling. An example is presented highlighting the differences in fracturing in the hanging wall and footwall during lithospheric extension superimposed on a primary (igneous) cooling fracture network. Results suggest that during flexural uplift, the hanging wall is significantly more deformed than the footwall, implying the former is more prone to fracturing than the footwall for both kinematic and flexural isostatic processes.