Engineering Geological, Geotechnical and Geohazard Modelling for Offshore Abu Dhabi, UAE

This paper presents the development of an engineering geological, geotechnical and geohazard model for four oil and gas fields offshore of Abu Dhabi in the Arabian Gulf. The purpose of the model was to characterize the shallow ground conditions for the design of offshore platforms and other infrastructure. The model was developed based on the interpretation of nearly 60 years of ground engineering data including a vast amount of boreholes, laboratory test and cone penetration test data. Carbonate-rich sediments dominate the shallow geology of Abu Dhabi offshore region. The main lithological units of Miocene to Pleistocene age comprise weak carbonate rocks, calcarenite and calcisiltite, with frequent lenses and pockets of gypsum. These units are overlain by recent carbonate marine deposits. The geological models for the region were developed using the software package GSI3D™. Geostatistical methods were applied in the treatment of geological uncertainty in the model, and the analysis of the associated geotechnical design recommendations. The model also includes a detailed review of local and regional natural hazards, including seismic and submarine geohazards, with the potential to affect existing and proposed offshore infrastructure. Interrogation of the model enables effective decision-making on oil and gas development issues related to offshore ground investigation for the siting of new developments. This model can allow these works to be optimized at the advanced stages of planning, saving on time, cost and significantly reducing health, safety and environmental risks.