Regional Assessment of the Upper Jurassic Hanifa and Tuwaiq Mountain Formations, Abu Dhabi: Implications for Prospectivity

Abstract

AbstractThe Hanifa and Tuwaiq Mountain formations (Upper Jurassic Sila Group) are underexplored units in Abu Dhabi. Although there are several discoveries from the Hanifa Formation, both onshore and offshore, and encouraging indications in the Tuwaiq Mountain Formation, the conventional potential of these formations has not been fully realised. Uncertainties exist between onshore-offshore and west-east correlations, with conflicting stratigraphic terminologies, and the distribution of the Hanifa and Tuwaiq Mountain formations across Abu Dhabi, particularly details of facies distributions and transitions and their impact on the distribution of depositional environments through time.To reduce uncertainties and unlock resources a fully integrated study of the lower Sila Group across Abu Dhabi Emirate has been undertaken. Approximately 150 wells were correlated and integrated with the interpretation of six regional seismic transects (3 W-E and 3 N-S). More detailed interpretation over areas with 3-D seismic coverage helped to improve stratigraphic understanding. Cored wells were used to refine sedimentological interpretationsand extrapolated into uncored wells.Resolution of stratigraphic uncertainties mean that, for the first time, there are consistent lithostratigraphic and sequence stratigraphic schemes across Abu Dhabi Emirate that provide a reliable framework for basin modelling and play mapping. Furthermore, integration of all the sub-studies has led to the development of new depositional models and more detailed GDE maps. These are important inputs to basin modelling and the development of revised play maps that clearly highlight the prospective areas in Abu Dhabi. Focus on these prospective areas has led to the recognition of a significant number of structural leads and three new stratigraphic play concepts. These concepts include: a truncation trap geometry to the east,a possible collapse/mass movement trap on the slope, anda possible combined stratigraphic/structural trap where four-way dip closures overlap both the shoal and the slope, with the facies change to muddier slope deposits providing potential down-dip seal.