Abstract The Nukhul Formation (Suez rift) consists of fluvial and tidally influenced shallow marine strata that were deposited in fault-controlled seaways and tidal embayments during rift initiation. In this study, we create a half-graben-scale, high-resolution (typical grid cell dimensions 20 m x 20 m x <1 m), geocellular outcrop model of the Nukhul Formation. The evolution of the normal fault system in the study area is associated with the development of fault-parallel and fault-perpendicular folds. The changing nature of the structural template, and the resulting geomorphology, during deposition led to complex syn-rift stratigraphic architecture and facies distributions. We use a LIDAR-based digital outcrop approach to map this geological complexity to a high degree of accuracy, for export to reservoir modelling software. Software developed in-house was used to integrate field observations with the digital dataset, aid interpretation, and create realistic surface meshes from outcrop data. Facies modelling used a combination of sequential indicator simulation and object-based modelling approaches. Sedimentary logs were attached to the dataset and used as conditioning data. 2D probability maps, source points, and flow lines constrained the geocellular outcrop model to match the known geology. The approach leads to improvements in three areas: (i) geological knowledge of the study area, (ii) data portability, and (iii) geocellular outcrop modelling. Comparison between the final geocellular outcrop model, outcrop geology, and inferred palaeogeography shows that the geology of the Nukhul Formation is realistically modelled. The final reservoir model can be used as an analogue for similar geological settings. It can be applied to improve the prediction of subsurface geology in analogous reservoirs and to increase the accuracy of static connectivity and flow simulations. Ultimately this will improve knowledge of the impact of facies heterogeneities on reservoir performance and lead to increased efficiency of reservoir drainage.

Abstract The Vardar Zone documents the Mesozoic–Early Cenozoic evolution of several small oceanic basins and a complex history of terrane assembly. Following a Hercynian phase of deformation and granitic intrusion within the Pelagonian Zone to the west, the Vardar Zone rifted in Permian–Triassic time, with the creation of an oceanic basin (Almopias Ocean) during the Late Triassic–Early Jurassic. During the Mid-Jurassic, this ocean subducted northeastwards beneath the Paikon Zone and the Serbo-Macedonian Zone, giving rise to arc volcanism and back-arc rifting. A second ocean basin, the Pindos Ocean, opened to the west of a Pelagonian microcontinent, also during Late Triassic–Early Jurassic time. During the Mid–Late Jurassic, ophiolites were emplaced northeastwards (in present co-ordinates) from the Pindos Ocean onto the Pelagonian microcontinent, forming the Pelagonian ophiolitic mélange within a flexural foredeep. This emplacement is dated at pre-Late Oxfordian–Early Kimmeridgian from the evidence of corals within neritic carbonates that depositionally overlie the emplaced ophiolitic rocks in several areas. Related greenschist- or amphibolite-facies metamorphism is attributed to deep burial following trench–margin collision and the attempted subduction of the Pelagonian continent. An inferred phase of NNW–SSE displacement, also of pre-latest Jurassic age, imparted a regionally persistent stretching lineation and related ductile fabric, apparently related to post-collisional strike-slip. The Pelagonian Zone and its emplaced ophiolitic rocks then underwent extensional exhumation during Late Jurassic–Early Cretaceous time. The western margin of the Vardar Zone experienced extensional (or transtensional) faulting, neritic carbonate and terrigenous clastic deposition, and intermediate–silicic magmatism during Late Jurassic–Early Cretaceous time. Oceanic crust (Meglenitsa Ophiolite) formed further east in the Vardar Zone during Late Jurassic–Early Cretaceous time, possibly above a subduction zone. A near-margin setting is suggested by the presence of a deep-water terrigenous cover, probably derived from the Paikon continental unit to the east. The Vardar Zone as a whole finally closed related to eastward subduction beneath Eurasia, culminating in collision with the Pelagonian microcontinent during latest Cretaceous–Eocene time, as recorded in foreland basin development, HP–LT metamorphism, ophiolite emplacement and large-scale westward thrusting. In contrast to models that suggest closure of the Vardar Ocean in the Mid–Late Jurassic, followed by reopening of a Cretaceous ocean, we believe that the Vardar Ocean remained partly open from Triassic to Late Cretaceous–Early Cenozoic time.