How to Calculate and Solve for Total Formation Volume Factor | The Calculator Encyclopedia

June 26, 2019February 28, 2024 Loveth Idoko

Last Updated on February 28, 2024

To calculate the total formation volume factor (FVF), four essential parameters are needed, and these parameters are oil FVF (B_o), gas FVF (B_g), initial gas solubility (R_si) and current gas solubility (R_s).

The formula for calculating the total FVF:

B_T = B_o + (R_si – R_s)B_g

Where;

B_T = Total FVF
B_o = Oil FVF
B_g = Gas FVF
R_si = Initial Gas Solubility
R_s = Current Gas Solubility

So, let’s solve an example;
Find the total FVF when the oil FVF is 14, gas FVF is 15, initial gas solubility is 26, and current gas solubility is 17.

This implies that; B_o = Oil FVF = 14

And then,

B_g = Gas FVF = 15
R_si = Initial Gas Solubility = 26
R_s = Current Gas Solubility = 17

That is, B_T = B_o + (R_si – R_s)B_g
B_T = 14 + (26 – 17)15
B_T = 14 + (9)15
So, B_T = 14 + 135
B_T = 149

Therefore, the total FVF is 149.

Calculating the Oil FVF when the Total FVF, Gas FVF, Initial Gas Solubility and Current Gas Solubility are Given

B_o = B_T – (R_si – R_s)B_g

Where;

B_o = Oil FVF
B_T = Total FVF
B_g = Gas FVF
R_si = Initial Gas Solubility
R_s = Current Gas Solubility

Let’s solve an example;
Find the oil FVF when the total FVF is 44, gas FVF is 17, initial gas solubility is 21, and current gas solubility is 19.

This implies that; B_T = Total FVF = 44

Then, B_g = Gas FVF = 17
R_si = Initial Gas Solubility = 21
R_s = Current Gas Solubility = 19

B_o = B_T – (R_si – R_s)B_g
B_o = 44 – (21 – 19)17
So, B_o = 44 – (2)17
B_o = 44 – 34
B_o = 10

Therefore, the oil FVF is 10.

Calculating the Gas FVF when the Total FVF, Oil FVF, Initial Gas Solubility and Current Gas Solubility are Given

B_g = ^{B_T – B_o} / _{R_si – R_s}

Where;

B_g = Gas FVF
B_o = Oil FVF
And B_T = Total FVF
R_si = Initial Gas Solubility
R_s = Current Gas Solubility

Let’s solve an example;
Find the gas FVF when the total FVF is 48, oil FVF is 16, initial gas solubility is 20 and current gas solubility is 12.

This implies that; B_o = Oil FVF = 16
And then, B_T = Total FVF = 48
R_si = Initial Gas Solubility = 20
R_s = Current Gas Solubility = 12

B_g = ^{B_T – B_o} / _{Rsi – Rs}
B_g = ^{48 – 16} / _{20 – 12}
So, B_g = ³² / ₈
B_g = 4

Therefore, the gas FVF is 4.

Calculating the Initial Gas Solubility when the Total FVF, Gas FVF, Oil FVF and Current Gas Solubility are Given

R_si = ^{B_T – B_o} / _{B_g} + R_s

Where;

R_si = Initial Gas Solubility
B_T = Total FVF
So, B_g = Gas FVF
B_o = Oil FVF
R_s = Current Gas Solubility

In that case, let’s solve an example;
Find the initial gas solubility when the total FVF is 54, oil FVF is 14, gas FVF is 12 and current gas solubility is 24.

Hence, this implies that;

B_T = Total FVF = 54
Then, B_g = Gas FVF = 14
B_o = Oil FVF = 12
Hence, R_s = Current Gas Solubility = 24

This means, R_si = ^{B_T – B_o} / _{B_g} + R_s
R_si = ^{54 – 12} / ₁₄ + 24
Then, R_si = ⁴² / ₁₄ + 24
R_si = 3 + 24
R_si = 27

Therefore, the initial gas solubility is 27.

Calculating the Current Gas Solubility when the Total FVF, Gas FVF, Oil FVF and Initial Gas Solubility are Given

R_s = R_si – ^{B_T – B_o} / _{B_g}

Where;

R_s = Current Gas Solubility
R_si = Initial Gas Solubility
B_T = Total FVF
So, B_g = Gas FVF
B_o = Oil FVF

In that case, let’s solve an example;
Find the current gas solubility when the total FVF is 14, oil FVF is 6, gas FVF is 10 and initial gas solubility is 5.

This implies that;

R_si = Initial Gas Solubility = 5
B_T = Total FVF = 14
B_g = Gas FVF = 10
That is, B_o = Oil FVF = 6

R_s = R_si – ^{B_T – B_o} / _{B_g}
R_s = 5 – ^{14 – 6} / ₁₀
So, R_s = 5 – ⁸ / ₁₀
R_s = 5 – 0.8
R_s = 4.2

Therefore, the current gas solubility is 4.2

How to Calculate Total Formation Volume Factor Using The Calculator Encyclopedia

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

So, to get the answer and workings of the total 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

Next, Click on Reservoir Fluid Flow under Petroleum

Then, Click on Total FVF under Reservoir Fluid Flow

So, the screenshot below displays the page or activity to enter your value to get the answer for the total FVF according to the respective parameters, which are the oil FVF (B_o), gas FVF (B_g), initial gas solubility (R_si) and current gas solubility (R_s).

Now, enter the value appropriately and accordingly for the parameter as required by the oil FVF (B_o) is 14, gas FVF (B_g) is 15, initial gas solubility (R_si) is 26 and current gas solubility (R_s) is 17.

Finally, Click on Calculate

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