Charalampos Poulis, "Comparison of density calculation methods applied to real reservoir fluids", Master Thesis, School of Mineral Resources Engineering, Technical University of Crete, Chania, Greece, 2018
https://doi.org/10.26233/heallink.tuc.79291
Gas density as well as its derivative, are necessary in almost every upstream petroleum engineering calculation. Calculations in the wellbore are directly related to the hydrostatic head and hence directly related to the petroleum fluid density. Calculations in the reservoir are on the other hand mostly related to the fluid’s compressibility or in other words density’s first derivative with respect to pressure.Density calculation is directly related to compressibility z factor calculation and therefore the one problem reduces into another. The most common sources of compressibility z factor values are experimental measurement, equations of state and empirical correlations. Necessity for z factor values prediction arises when there is no available experimental data for the required composition, pressure and temperature conditions. In the present master thesis, a large database of real reservoir fluid PVT properties is utilized, where the z factor has been experimentally measured for various pressure values above the dew point pressure in the monophasic region.Industry’s most commonly used z factor calculation methods were implemented using Microsoft Excel® and Mathworks Matlab® where appropriate. The results from the various methods implemented were compared to the experimental measurements while the methods were finally evaluated in terms of their quality and performance.