Improved PVT correlations for UAE crude oils

Current empirical correlations to evaluate crude oil PVT properties are based on data from different parts in the world and are more accurate for use with crudes from the same basins for which the data was correlated. Standing correlation, for example, used California crudes. Glaso's used North Sea crudes. Al-Marhoun's used Middle East crudes. Petrosky and Farshad used Gulf of Mexico crudes, and Dokla and Osman produced a correlation based on UAE offshore crude oil samples. A few other correlations were based on a very large number of samples from different regions. The most widely used of these is the Vasquez and Beggs correlation. The universal correlations, however, are less accurate than regional correlations, when they are available, because of the scatter involved by using a large number of data. The UAE fields are very significant and constitute around 10% of reserves worldwide. In this work, experimental PVT measurements from around 15 reservoirs located in the UAE were used to test the validity of commonly used PVT correlations. The data then was used to construct a new set of empirical correlations which were also tested against the experimental values. Results indicate that the new correlations reduced the error involved in estimating the bubble point pressures and the oil formation volume factor to within less than half the range of error associated with commonly used correlations when compared to experimental values. The physical properties correlated include the oil formation volume factor at the bubble point, the bubble point pressure, the oil compressibility (in order to get the oil formation volume factor above the bubble point pressure), and the oil viscosity at the bubble point and above the bubble point.