A Consistent and Accurate Dead-Oil-Viscosity Method (2007)

A Consistent and Accurate Dead-Oil-Viscosity Method David F. Bergman; David F. Bergman BP America Search for other works by this author on: This Site Google Scholar Robert P. Sutton Robert P. Sutton Marathon Oil Company Search for other works by this author on: This Site Google Scholar Paper presented at the SPE Annual Technical Conference and Exhibition, Anaheim, California, U.S.A., November 2007. Paper Number: SPE-110194-MS https://doi.org/10.2118/110194-MS Published: November 11 2007 Cite View This Citation Add to Citation Manager Share Icon Share MailTo Twitter LinkedIn Get Permissions Search Site Citation Bergman, David F., and Robert P. Sutton. "A Consistent and Accurate Dead-Oil-Viscosity Method." Paper presented at the SPE Annual Technical Conference and Exhibition, Anaheim, California, U.S.A., November 2007. doi: https://doi.org/10.2118/110194-MS Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll ProceedingsSociety of Petroleum Engineers (SPE)SPE Annual Technical Conference and Exhibition Search Advanced Search Abstract The calculation of pressure drop resulting from the flow of oil through porous media or pipes requires the evaluation of viscosity. This is the single most important transport property necessary to accurately calculate pressure drop. The basis for oil viscosity calculations using a traditional black oil approach is the determination of dead or gas free oil viscosity.A total of 23 dead oil viscosity calculation methods have been identified from the literature and evaluated in this paper. A large database consisting of data from conventional PVT reports, crude oil assays and the literature was compiled from over 3000 samples from around the world. The number of actual viscosity measurements exceeded 9800. An evaluation of the correlations yielded unacceptable results largely due to the failure of the methods to properly account for the physics of the problem. In general this results from the methods' failure to properly account for the change in viscosity with temperature and to address the chemical nature of the oil. A significant improvement in results can be realized through the use of the Watson characterization factor in addition to oil API gravity and temperature in the correlation of viscosity. This work has identified the character of the crude to have a significant effect on oil viscosity especially for oils with gravities less than 25 API.Methods have been proposed in the literature that utilize the Watson characterization factor; however, these have been largely ignored in the upstream oil industry. Therefore, a new method has been developed which shows significant improvement over existing methods. At reservoir conditions, a 2-13 fold reduction in average absolute error was noted when compared with the error observed from traditional methods. At surface process conditions, this improvement ranged 3-60 fold. In addition, an updated correlation for Watson characterization has been developed. The ASTM density correction for changing temperature has been examined. Revised coefficients were developed which enhance the method's accuracy for both oils and pure components and provide a suitable means to convert kinematic viscosity to absolute viscosity. Keywords: spe 110194, correlation, crude oil, API gravity, PVT measurement, characterization factor, average absolute error, temperature range, accuracy, viscosity Subjects: Fluid Characterization, Phase behavior and PVT measurements Copyright 2007, Society of Petroleum Engineers You can access this article if you purchase or spend a download.