Determination of Water Saturation Based on Well Logging in Mishrif Carbonate Reservoir

Water saturation is calculated by many models that developed over the years based on known physical principles or on empirically derived relationships. The accurate determination of water saturation in complex carbonate reservoirs is the most challenging aspects of well log analysis. The complex formation under study is Mishrif carbonate formation which is one of the deepest hydrocarbons bearing zone in the Nasiriya oilfield in south of Iraq. The available scanned copes of well logs are digitalized by using Neurolog software. Schlumberger charts 2005 had been used for environmental corrections. These correction charts are supplied in the Interactive Petrophysics software. Simple Archie equation, Dual water model, and Indonesia model have been used to calculate water saturation of Mishrif carbonate formations. After making the environmental corrections, the porosity interpretation shows that the logging tools have a good quality of data reading. From Indonesian model, the water saturation for Mishrif formation is ranged from 0.25 to 0.41. This study is provided water saturation values with depth that should use to calculate original oil in place and detect the perforation zones in the pay zone using Interactive Petrophysics software.