PVT Report includes many important properties of the reservoir fluid. One of the most important properties is Oil formation volume factor(Bo).
Oil Formation Volume Factor (FVF) “known as Bo” is simply the ratio between the volume of oil at Standard conditions in “STB” to the volume of oil at pressure and temperature of the reservoir in “bbl”. The general behavior of Bo,as shown in the below figure, appears in certain types of reservoirs such as Undersaturated Depletion Drive Reservoir. The value of Bo is always greater than 1 due to the existence of dissolved gas in the oil within the formation. Bo increases with decreasing the pressure as far as Pr is greater than Bubble Point Pressure “Pb” due to the expansion of the dissolved gas. However, Bo decreases with decreasing the pressure below the bubble point as the gas starts to liberate from the oil leaving the liquid phase. Bo can be measured at the lab using a device called PVT cell.
The below graph is a general graph and taken as an example.