## How to Calculate and Solve for Gas Formation Volume Factor (FVF) | The Calculator Encyclopedia The image above represents the gas FVF.

To compute for the gas FVF, three essential parameters are needed and these parameters are Z-Factor (Z), Temperature (T) and Pressure (P).

The formula for calculating the gas FVF:

Bg = 0.00504[ZT / P]

Where;

Bg = Gas FVF
Z = Z-Factor
T = (°R) Temperature
P = Pressure

Let’s solve an example;
Find the Gas FVF when the Z-Factor is 12, temperature is 30 and the pressure is 120.

This implies that;

Z = Z-Factor = 12
T = (°R) Temperature = 30
P = Pressure = 120

Bg = 0.00504[ZT / P]
Bg = 0.00504[12 x 30 / 120]
Bg = 0.00504[360 / 120]
Bg = 0.00504
Bg = 0.01512

Therefore, the gas FVF is 0.01512 bbl / scf.

Calculating for the Z-Factor when the Gas FVF, Temperature and Pressure is Given.

Z = Bg.P / 0.00504T

Where;

Z = Z-Factor
Bg = Gas FVF
T = (°R) Temperature
P = Pressure

Let’s solve an example;
Find the Z-Factor when the Gas FVF is 22, temperature is 16 and the pressure is 80.

This implies that;

Bg = Gas FVF = 22
T = (°R) Temperature = 16
P = Pressure = 80

Z = Bg.P / 0.00504T
Z = 22 x 80 / 0.00504 x 16
Z = 1760 / 0.08064
Z = 21825.39

Therefore, the Z-Factor is 21825.39.

Calculating for the Temperature when the Gas FVF, Z-Factor and the Pressure is Given.

T = Bg.P / 0.00504Z

Where;

T = (°R) Temperature
Z = Z-Factor
Bg = Gas FVF
P = Pressure

Let’s solve an example;
Find the Temperature when the Gas FVF is 44, Z-Factor is 29 and the pressure is 70.

This implies that;

Z = Z-Factor = 29
Bg = Gas FVF = 44
P = Pressure = 70

T = Bg.P / 0.00504Z
T = 44 x 70 / 0.00504 x 29
T = 3080 / 0.14616
T = 21072.79

Therefore, the temperature is 21072.79.