Yordi Asks PERM:
In this moment we have many problems with properties of fluid because the oils have high viscosity (4000 to 10000 cP at Temperature of reservoir).
All equations of viscosity have two parameters (density or API and Temperature)
For example the correlation Beal
This correlation has application in light oils but in extra heavy oils show a lot of deviation.
I’ve done many tests to study the viscosity behavior and think that the extra heavy oil have other parameters with full influence in the viscosity.
Do you have any advanced course of viscosity for extra heavy oils? I very interesting in this study because the viscosity have influence in the production of the well.
Dr. Jonathan Bryan from PERM Answers:
You are absolutely correct: temperature and pressure alone with density are not sufficient parameters to be able to predict the viscosity of a given heavy oil or bitumen. These are all indicators of oil viscosity, but to be truly predictive we need to know something about the oil, i.e. its makeup or structure.
It is known that what leads to higher oil viscosity is larger and more complex molecules, so there have been studies that examine the relationship between viscosity and SARA fraction, or the asphaltene content in a given crude oil. Like with density, higher asphaltenes are an indication of a more viscous oil. But again, indicators are not useful as predictors.
In most labs (including ours) we measure viscosity directly and use this data as a means for making tuned viscosity correlations for different tested oils. There are tools that you can use to monitor viscosity in changing liquid mixtures, or liquids under high T&P. One such tool is NMR, where the properties of the spectrum can be directly correlated with the oil viscosity. This is a larger topic to get into but the end result is that viscosity needs to be measured either directly (viscometer measurements) or indirectly (NMR) for individual oil systems. There is a free video series (you must register) for introduction to NMR and also we have a 2-day full course on using NMR for Reservoir Characterization.
Dr. Jonathan Bryan