Integrated Approach to Delineate Stratigraphic Prospect of Carbonate Shoal, Mishrif Formation, Western UAE

Summary As the unique stratigraphic oil field in Mishrif formation, UAE, the NN field is composed of porous grainstone and laterally sealed by micrite-rich wackestone-packstone. Core observation and thin-section description concluded that the reservoir was controlled by the primary depositional facies as well as lateral diagenesis. The sediments in the paleo-geomorphology highs underwent lateral aerial erosion which contributed to the vuggy and dissolution pores. RCA indicated similar porosity (15–25%) for hydrocarbon saturated grainstone and water-bearing wackestone-packstone while permeability is the key points for hydrocarbon entrapment. Considering the challenges in paleo-morphology delineation and seismic illustration, an integrated approach involving sequence stratigraphic study, paleo-geographic demonstration, AVO & Pre-stack inversion was dedicated and mitigated the uncertainty in reservoir characterization. Key points in this study lie in figuring out sequence interfaces such as FFS and MFS and using into the paleo-morphology delineation by dual-interfaces method. AVO response from well forward modeling and elastic parameter cross-plot prove the feasibility of AVO &pre-stack inversion in the targeted interval. Close combination of sequence stratigraphy, paleo-geography and AVO & Pre-stack inversion de-risks the uncertainty in thin reservoir characterization and fluid behavior demonstration, which proved to be reasonable by the subsequent proposed drilling.