Mixing Fluids of Different Densities without Pit Space Limitation

According to the previous post, you have learnt about Mixing Fluids of Different Densities with Pit Space Limitation. This post you will learn about how to mix different fluid densit withour limitation of mud pit space (Case#2: You don’t have limitation of pit space). For this case, the calculation will be easier because you can directly input value of each variation into the equation to get answer.

First of all, let’s review the formula for mixing fluid density.

(V1 x D1) + (V2 x D2) = VF x DF


V1 = volume of fluid 1 (bbl, gal, etc.)

D1 = density of fluid 1 (ppg,lb/ft3, etc.)

V2 = volume of fluid 2 (bbl, gal, etc.)

D2 = density of fluid 2 (ppg,lb/ft3, etc.)

VF = volume of final fluid mix

DF = density of final fluid mix

Let’s read and understand this example so you will know how to use the formula.

Example 2: No limit is placed on volume:

Determine the final mud weight and the final volume when mixing 10.0 ppg and 14.0 ppg drilling mud. There is no limitation regarding the pit space.

Mud in mud pits :

200 bbl of 10.0 ppg mud in pit A

300 bbl of 14.0 ppg mud in pit B


Apply formula of mixing different fluid density.

(V1 x D1) + (V2 x D2) = VF x DF


V1 = 200 bbl

D1 = 10.0 ppg

V2 = 300 bbl

D2 = 14.0 ppg

VF = V1+V2 =500 bbl

Formula: (V1 x D1) + (V2 x D2) = VF x DF

(200x 10.0) + (300 x 14.0) = 500 x DF

12.4 ppg = DF

You will have total fluid 500 bbl of 12.4 ppg.

Please find the Excel sheet to calculate how to mix different fluid density without pit space limitation.

Ref book: Drilling Formula Book Formulas and Calculations for Drilling, Production and Workover, Second Edition

Related Post

Depth of Washout Pipe Washout in drill string can cause big problem later such as parted drill string. When we see stand pipe pressure decrease without changing any paramet...
Water Kick and Oil Kick Indications All of well control articles in this website are based on gas kick assumption. Therefore, all the responses as bottom hole pressure, surface pressure,...
Starting volume of original mud (weight up with Ba... You know how much volume will be increased due to adding barite into the system; however, you sometimes are limited to total volume due to limit pit v...
What is slug mud? How much volume and weight of sl... Slug Mud: It is heavy mud which is used to push lighter mud weight down before pulling drill pipe out of hole. Slug is used when pipe became wet while...
Share the joy
  • 18
Tagged , , . Bookmark the permalink.

About DrillingFormulas.Com

Working in the oil field and loving to share knowledge.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.