oa The Barik Sandstone Member, northern Oman: Stratigraphic traps and review of a tight gas play

The Barik Sandstone Member (Cambrian-Ordovician Haima Supergroup) in northern Oman is the most productive deep and tight gas unit in Oman. The majority of existing discoveries are conventional structural closures but much of the remaining potential resides in stratigraphic traps. The Barik Sandstone Member comprises a variety of reservoir facies within an overall continental braid-plain to marginal marine/offshore setting. Through time, the position of the Barik coastline oscillated across northern Oman. Better reservoir developments are associated with sand-rich, fluvial-dominated systems, contemporaneous with regional progradational events, and exhibit abrupt contacts with adjacent marine mud-prone intervals. These progradational units are probably a result of forced regression. Barik stratigraphic-trap configurations rely on the northerly pinchout of these sandstone systems. Major flooding surfaces, ichnofacies and magnetostratigraphy have assisted in defining a detailed intra-reservoir, regional correlation<br>framework for the barren beds of the Barik Sandstone Member. This framework gives some regional control on intra-Barik reservoir distribution and connectivity and facilitates improved understanding of local changes in palaeogeography, providing a correlation resolution of less than one million years. With limitations on the seismic definition of reservoir distribution regional, Barik well penetrations, integrated with outcrop studies, provide the main input into geological models for the Barik Sandstone Member and the basis for play maps. All data have been used in facies modelling, core-log calibration, depositional environment interpretation, provenance, palaeocurrent analysis and reservoir quality determination. These parameters have been mapped to generate play maps that assist in defining and testing the stratigraphic pinchout traps in the Barik Sandstone Member and in early appraisal activities in discovered stratigraphic traps.