How to Calculate and Solve for Gas Formation Volume Factor (FVF) | The Calculator Encyclopedia

July 5, 2019March 7, 2024 Loveth Idoko

Last Updated on March 7, 2024

Three essential parameters are needed to calculate the gas formation volume factor (FVF): Z-Factor (Z), Temperature (T), and Pressure (P).

The formula for calculating the gas FVF:

B_g = 0.00504[^ZT / _P]

Where;

B_g = 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

B_g = 0.00504[^ZT / _P]
B_g = 0.00504[^{12 x 30} / ₁₂₀]
So, B_g = 0.00504[³⁶⁰ / ₁₂₀]
B_g = 0.00504[3]
B_g = 0.01512

Therefore, the gas FVF is 0.01512 ^bbl / _scf.

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

Z = ^B_g.P / _0.00504T

Where;

Z = Z-Factor
B_g = 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;

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

Z = ^B_g.P / _0.00504T
Z = ^{22 x 80} / _{0.00504 x 16}
Then, 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 are Given

T = ^B_g.P / _0.00504Z

Where;

T = (°R) Temperature
Z = Z-Factor
B_g = 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
B_g = Gas FVF = 44
P = Pressure = 70

T = ^B_g.P / _0.00504Z
T = ^{44 x 70} / _{0.00504 x 29}
So, T = ³⁰⁸⁰ / _0.14616
T = 21072.79

Therefore, the temperature is 21072.79.

Calculating for the pressure when the Gas FVF, Z-Factor and the Temperature are Given

P = ^{0.00504 (ZT)} / _{B_g}

Where;

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

Let’s solve an example;
Find the pressure when the Gas FVF is 52, Z-Factor is 32 and the Temperature is 90.

This implies that;

B_g = Gas FVF = 52
T = (°R) Temperature = 90
Z = Z-Factor = 32

P = ^{0.00504 (ZT)} / _{B_g}
P = ^{0.00504 (32 x 90)} / ₅₂
That is, P = ^{0.00504 (2880)} / ₅₂
P = ^14.5152 / ₅₂
P = 0.279

Therefore, the pressure is 0.279.

How to Calculate Gas Formation Volume Factor (FVF) Using The Calculator Encyclopedia

Nickzom Calculator – The Calculator Encyclopedia is capable of calculating the gas FVF.

To get the answer and workings of the gas FVF using the Nickzom Calculator – The Calculator Encyclopedia. First, you need to obtain the app.

You can get this app via any of these means:

Web – https://www.nickzom.org/calculator-plus

To get access to the professional version via web, you need to register and subscribe for NGN 1,500 per annum to have utter access to all functionalities.
You can also try the demo version via https://www.nickzom.org/calculator

Android (Paid) – https://play.google.com/store/apps/details?id=org.nickzom.nickzomcalculator
Android (Free) – https://play.google.com/store/apps/details?id=com.nickzom.nickzomcalculator
Apple (Paid) – https://itunes.apple.com/us/app/nickzom-calculator/id1331162702?mt=8
Once, you have obtained the calculator encyclopedia app, proceed to the Calculator Map, then click on Petroleum under Engineering

Now, Click on Fluid Properties under Petroleum

Now, Click on Gas FVF under Fluid Properties

The screenshot below displays the page or activity to enter your values, to get the answer for the gas FVF according to the respective parameters which are the Z-Factor (Z), Temperature (T) and Pressure (P).

Now, enter the values appropriately and accordingly for the parameters as required by the Z-Factor (Z) is 12, Temperature (T) is 30 and Pressure (P) is 120.

Finally, Click on Calculate

As you can see from the screenshot above, Nickzom Calculator– The Calculator Encyclopedia solves for the gas FVF and presents the formula, workings and steps too.