Mud balance

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A mud balance, also known as a mud scale is a device used to measure the density (weight) of drilling fluid,[1] cement[2] or any type of liquid or slurry.

Description and operation[edit]

It consists of a graduated beam with a bubble level and a weight slider along its length and a cup with a lid on one end. The cup is used to hold a fixed amount of fluid so it can be weighed. A slider-weight can be moved along the beam, and a bubble indicates when the beam is level. Density is read at the point where the slider-weight sits on the beam at level.

Calibration is done using a liquid of known density (often fresh water) by adjusting the counter weight. Typical balances are not pressurized, but a pressurized mud balance operates in the same manner.[3]

Reason for use[edit]

There is no reliable visual method of determining the density of drilling mud; the mud balance is the most reliable and simple way of making the determination.[4]


  1. ^ Chilingar, George V.; Paul Vorabutr (1983). Drilling and drilling fluids. Elsevier. pp. 121 ff. ISBN 978-0-444-42177-7.
  2. ^ Henn, Raymond W. (2003). AUA guidelines for backfilling and contact grouting of tunnels and shafts. ASCE Publications. pp. 214–215. ISBN 978-0-7844-0634-2.
  3. ^ Schlumberger's oil field glossary
  4. ^ Dean Bennett testing equipment