Heterogeneities on a Jurassic carbonate ramp (UAE) as analogues for reservoirs in the Middle East
M. Hönig1 and C. John1
Carbonate rocks are major hydrocarbon reservoirs across the world and especially in the Middle East. Capturing the spatial distribution and dimensions of sedimentary facies and diagenetic heterogeneities is of interest for reservoir modeling and for the understanding of process sedimentology. However, these heterogeneities and the exact causal link with the processes that control them are still poorly understood. Here we present data from a Jurassic carbonate ramp outcropping on the Musandam Peninsula (Northern United Arab Emirates), which serves as an analogue for the hydrocarbon bearing units in the subsurface of the Middle East, especially of Qatar and the UAE. Firstly facies distribution and architecture along a 1400 m x 120 m continuous Middle Jurassic outcrop were captured at an inter-well scale of 350 m. Secondly, the dimensions of Lower Jurassic cross-stratified oolithic shoals, including small-scale internal heterogeneities were measured and analysed in detail. Thirdly, the internal architecture of a selectively dolomitized interval, which can be traced over 10’s of kilometres in the Lower Jurassic of the Musandam Peninsula were investigated. Outcrop observations are combined with detailed thin section analysis and complemented with stable isotope analysis (carbon and oxygen) to help age control of the outcropping strata through chemostratigraphy and to determine the palaeoceanographic conditions controlling the deposition of different facies types. The results show that the Middle Jurassic facies are mostly continuous at the scale investigated with slight changes in bed thicknesses. Future work will focus on carbon isotope stratigraphy of the Jurassic ramp and investigations of how carbon cycle perturbations throughout the Jurassic impacted on carbonate deposition and reservoir quality throughout the Middle East.
AAPG Search and Discovery Article #90188 ©GEO-2014, 11th Middle East Geosciences Conference and Exhibition, 10-12 March 2014, Manama, Bahrain