Knowledge of pressure-volume-temperature (PVT) parameters is a requirement for all types of petroleum calculations such as determination of hydrocarbon flowing properties, design of fluid handling equipment and reservoir volumetric estimates.

The PVT properties can be obtained from laboratory experiment using representative samples of the crude oils. However, values of reservoir liquid and gas properties are often needed when laboratory detailed PVT data are not available. Therefore, correlations are used to estimate those properties.

The PVT properties depend on pressure, temperature, and chemical compositions. For the development of a correlation, geological condition is considered important because the chemical composition of crude oil differs from region to region. It is difficult to obtain the same accurate results through empirical correlations for different oil samples having different physical and chemical characteristics. Therefore to account for regional characteristics, PVT correlations need to be modified for their application by recalculating the correlation constants for the region of interest.

The frequently used empirical correlations for the prediction of oil density, bubblepoint pressure, solution gas/oil ratio (GOR), oil formation volume factor (FVF) at bubblepoint, total FVF, undersaturated oil compressibility, and oil viscosity are reviewed in the following sections.