Sedimentary and stratigraphic heterogeneities within 3rd order sequences in the Natih Formation (L. Albian-E.Turonian)

The Natih Formation (Late Albian -Early Turonian) corresponds to a very broad, extensive inner carbonate platform that developed in Oman over more than 1000 km. Because it is overall an aggrading carbonate platform system, the third-order stratigraphic sequences appear very tabular and isopach, which often leads to "layer-cake" correlations, even at the scale of the reservoirs. However, within these third-order sequences, a high level of sedimentary and stratigraphic heterogeneity can develop, and they are linked with: (1)the development and fill of intrashelf basins (different types of clinoforms), (2) phases of subaerial exposure (incisions and forced regressive wedges), and (3) phases of flooding of the platform (tidal channels and bioclastic shoals). These stratigraphic intervals have been studied on several outcrops of the Oman Mountains. The regional stratigraphic framework has been reviewed and extended by regional 3D seismic interpretation. A particular focus was made on specific reservoir-scale sediment bodies, on both outcrops and seismic data, and the technique of synthetic seismic modeling has been used to improve seismic interpretation. The results of this study have been used to refine the static model of the Natih Formation in a giant oil field in northern Oman.