Modeling viscosity of moderate and light dead oils in the presence of complex aromatic structure

摘要

Crude oil viscosity measurements are very crucial in the field of petroleum industries. Difficulties associated with obtaining accurate measured viscosity values for reservoir oils have turned the light to estimate viscosity through empirical correlations to alleviate these laboratory difficulties. This work is a supplementary study for a previous research work, done on Egyptian heavy crude oil samples, to cover all types of reservoir oils. The proposed work started with evaluating the previously published viscosity correlations that considered as a useful method to provide preliminary values for viscous oil reservoirs characterization. The obtained viscosity values showed poor performance of applying these correlations, as these correlations depend only on oil specific gravity and operating temperature. Therefore, there is a need for correlating a new effective viscosity model using asphaltene content as one of the main representative parameters. Asphaltene is considered as a complex aromatic structure which causes problems in reservoir oils. In this work, laboratory measurements have been made on five-hundred database points of Egyptian moderate and light dead oil samples obtained from different locations to build accurate viscosity correlation model. The best fit accurate empirical correlation has been found using multiple least-square nonlinear regression analysis for ranges of viscosity measurements from 23.06 to 43.18 (omicron)API. Testing of the new proposed viscosity model, with another set of laboratory measured viscosity data, shows high performance and accuracy in predicting Egyptian moderate and light dead crude oils viscosity as compared with literature viscosity correlations.