Sequence Stratigraphy-Based Geological Modeling of the Upper Thamama(Lower Cretaceous)Reservoirs of a Giant Abu Dhabi Oil Field,United Arab Emirates

摘要

Important hydrocarbon accumulations occur in platform carbonates of the Lower Cretaceous Kharaib(Barremian and Early Aptian)and Shuaiba(Aptian)formations(Upper Thamama Group)of Abu Dhabi.A new,sequence stratigraphy-keyed static(geological)model has been built for the Upper Thamama(Lower Cretaceous)Kharaib and Shuaiba formations.The Kharaib Formation contains two reservoir units(Lower Kharaib Reservoir Unit and Upper Kharaib Reservoir Unit).The overlying Shuaiba Formation is separated from the Kharaib Formation by the Upper Dense Zone(Hawar)and contains two reservoir units(Lower Shuaiba Reservoir Unit and Upper Shuaiba Reservoir Unit)only partly separated by dense intervals.Core and well-log data of a giant onshore oil field in Abu Dhabi,as well as outcrop data from Wadi Rahabah(Ras Al-Khaimah)were used to establish a sequence stratigraphic framework and a lithofacies scheme;applicable to all four reservoir units and the three dense zones.Six third-order composite sequences are composed of twenty-six fourth-order parasequence sets that form the basic building blocks of a new generation static model.On the basis of faunal content,texture,sedimentary structures,and lithologic composition,fourteen reservoir lithofacies and ten non-reservoir(dense)lithofacies are identified from core.Reservoir units range from lower ramp to shoal crest to near back shoal open platform environments.A new static(geological)model has been built to provide a more detailed reservoir description to the dynamic model to further optimize the field development plan.