Effect of salinity and temperature on water cut determination in oil reservoirs

In this study, system stability and water cut were evaluated via IR analysis and physicochemical properties of the tested mixture. Samples were prepared with different water cuts at a specified salinity and tested by IR. Different cations were also used in the water portion of the mixture to evaluate its effect of interaction and stability. In addition, the effect of water cut, temperature, salinity and cation type, and composition on specific gravity, API gravity, kinematic and dynamic viscosities and surface tension were investigated. The studied water content range was from 0 to 0.8 while temperature from 20 to 100 °C. Salinity effect up to 40,000 ppm was also evaluated. For each mixed ion solution, equivalent sodium concentrations and mixture resistivity were calculated. Relationships between water cut, major functional groups and mixture physicochemical properties were developed. Therefore, for a known property, water cut could be predicted.