Reduce mud weight by dilution

You sometimes need to reduce your mud weight in hole. The method to reduce mud weight is dilution. The concept of dilution is to add light weight fluid into heavy fluid and when they mix together whole drilling fluid weight will decrease. The light weight fluid frequently used are fresh water, sea water, base oil, diesel, synthetic oil, etc which are normally your based fluid.


You can calculate how much light weight fluid in barrel required reducing original mud weight to new mud weight with this following formula:

Mud weight reduction by diluting with light weight fluid

Light weight fluid volume in bbl = V1 x (W1 – W2) ÷ (W2 – Dw)


V1 = Intial volume in bbl

W1 = Initial drilling fluid weight in ppg

W2 = Final drilling fluid weight in ppg

Dw = Density of light weight fluid in ppg

Example: Determine the number of barrels of base oil 7.2 ppg (Dw) required to reduce 200 bbl (V1) of 13.8 ppg (W1) to 10.0 ppg (W2):

Light weight fluid volume in bbl = V1 x (W1 – W2) ÷ (W2 – Dw)

Light weight fluid volume in bbl = 200 x (13.8 – 10) ÷ (10 – 7.2)

Light weight fluid volume in bbl = 271.4 bbl

You need to mix 271.4 bbl of base oil 7.2 ppg into 200 bbl of 13.8 ppg in order to achieve final mud weight of 10.0 ppg

Please find the Excel Sheet to calculate mud dilution.

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

Related Post

Loss of Hydrostatic Pressure due to Lost Return In case of totally lost return, the annulus must be fully filled with fluid, normally water, as fast as we can. Water filled in annulus causes loss of...
Buoyancy Factor Table Free Download Buoyancy factor is the factor that is used to compensate loss of weight due to immersion in drilling fluid and you can find the calculation from here ...
Lost Circulation and Well Control Lost circulation is a situation when drilling fluid losses downhole because formation(s) is fractured. There are three levels of lost circulation whic...
What are the differences between Formation Integri... You may confuse between Formation Integrity Test (FIT) and Leak Off Test (LOT). They are different in this following aspect. Leak Off Test – you...
Share the joy
  • 91
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Your email address will not be published.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.