The Lower Cretaceous Thamama Group in Zakum oil field is the main reservoir of the northern offshore oil fields of Abu Dhabi, United Arab Emirates. This group consists of four formations in stratigraphic order as: Habshan, Lekhwair, Kharaib and Shuaiba, and the reservoir facies are developed in parts of Lekhwair Formation and lower sequence of Kharaib Formation.
In this study, the reservoir quality of Thamama III is evaluated through vertical and horizontal distribution of the different petrophysical parameters such as pay zone thickness, shale content, porosity, permeability, fluid resistivity, water saturation and hydrocarbon saturation in the zones of interest for three available logged wells. The study revealed that the most effective diagenetic events are characterized by intra-matrix dissolution, moldic porosity and fracturing.
These diagenetic events are followed locally by precipitation of well-crystalline rhombic dolomite partial cavity and fracture fillings. The study also documented the observed porosities ranging between 5% and 31.5%, and permeabilities from less than 1 to 100 md across the study area and the best reservoir characteristics are recorded towards northeastern direction, where the water saturation decreases and the porosity increases. |
