Toward reservoir oil viscosity correlation

Oil viscosity plays a key role in reservoir simulation and production forecasting, as well as planning thermal enhanced oil recovery methods and these make its accurate determination necessary. In this communication, the most frequently used oil viscosity correlations are evaluated using a large databank of Iranian oil reservoirs which were measured using a Rolling Ball viscometer (Ruska, series 1602). To evaluate the performance and accuracy of these correlations, statistical and graphical error analyses have been used simultaneously. Three of the most accurate correlations for each region, including dead oil viscosity, viscosity below bubble point, viscosity at bubble point and the under-saturated oil viscosity, are recommended for Iranian oil reservoirs. In the last step, four correlations are developed for Iranian oil reservoirs which have simplified functional format. Furthermore, the input data of the latter correlations are those ones that are easily measured in oil fields. The ranges of data used to develop these new correlations cover almost all Iranian oil reservoirs PVT data and consequently they could be reliable for prediction of other Iranian oil reservoirs viscosity. These new correlations are consistent across a wide range of parameters and offer increased accuracy than previously published correlations for viscosity prediction of Iranian oil reservoirs. © 2012 Elsevier Ltd.