An Empirical Approach for the Determination of Undersaturated Oil Viscosity

Abstract

Regional correlations are usually superior over universal ones because there is almost a similar crude composition and regular patterns of variation in oil composition of a specific region. Regional data have regular scattering in crude oil properties and therefore are easy to be correlated. Also, Iran is a major oil producer and has a significant portion of world oil reserves. Therefore, after a comprehensive review of undersaturated oil viscosity correlations (black oil models), a correlation was developed using a large database including 572 lab data points of different Iranian oil fields to estimate undersaturated oil viscosity. These data were chosen by screening of over 760 data points. Conventional regression analysis and new techniques were incorporated to obtain the optimum correlation. The proposed correlation includes minimum input parameters—pressure (P), bubble point pressure (Pb ), and bubble point viscosity (μ ob )—which are essential parameters in estimation of undersaturated oil viscosity (μ o ). A wide range of parameters are covered by the proposed correlation in which μ o , P, μ ob , and Pb are in the intervals of 0.0763–9.287 cp, 800–7,500 psia, 0.0726–7 cp, and 620–7,000 psia, respectively. Moreover, crude API varies from 18.8 to 56.5. Finally, literature correlations and the proposed one were evaluated; and the results demonstrated the proposed correlation predicted undersaturated oil viscosity with the least deviation. Average deviation of the proposed correlation was 2.79% for the correlation of this study.