"I don't know much about simulation because my name of disser is just to make PVT model. "
oooo, if that is the situation then I would make you work harder. In other words, as your adviser I would ask that you put in more effort to get the best results and graphically prove to me that you found the best fit

I would not be easy on you, as no one does a dissertation in one month.

OK, in a very simple model, Darcy's Eq., if you knew that you viscosity could be off by +- 15 %, you would put this variation into the equation and see how much your flow would change. Hence, you could estimate how much off you would be in estimating the flow rate if your only error was in estimating the viscosity. With more parameters you could use Monte Carlo Simulation to quantify probabilities in your errors.

For a simulation this would something like this

[link Point to another website Only the registered members can access]

[link Point to another website Only the registered members can access]