Improved correlations for fluid properties of UAE crude oils

Empirical correlations to evaluate crude oil fluid properties such as the formation volume factor, bubble point, viscosity, and oil compressibility above the bubble point are used extensively by petroleum and process engineers to perform calculations for subsurface and surface processes. The published correlations are mostly based on regional data, such as Standing's for California crudes, Petrosky and Farshad's for Gulf of Mexico crudes, and Glaso's for North Sea crudes. Use of these regional correlations is more appropriate for crudes from the same basins for which the correlation is derived. Other correlations, such as the Vasquez and Beggs correlation, are based on data from a very large number of samples coming from multiple regions. Eventhough one is tempted to use these "universal" correlations, the range of error for their predictions is, however, typically large due to the scatter involved in using a large number of data sets to generate these correlations. The UAE fields are quite significant and constitute around 9% of worldwide reserves. In this work, experimental PVT measurements from 15 medium to large fields located in the UAE are used to test the viability of using either regional or universal correlations to UAE crudes. In addition, a new set of empirical correlations is constructed based on these data, and their predictions are also compared. Statistical comparisons indicate that the new correlations developed in this paper reduce the error involved in predicting the bubble point pressures, the oil compressibility, and the oil formation volume factor to less than half the range associated with either the regional or the universal correlations. Also, new correlations for viscosity both at the bubble point and above the bubble point were constructed that gave better predictions for UAE oils over other commonly used correlations for viscosity.