Calcium Hardness – Water Based Mud Testing


The Calcium test gives an indication of the level of soluble Calcium ions present in the mud.

Such ions are considered detrimental since, under conditions of high pH (>11.5), they may render polymer treatments for viscosity and fluid loss less effective.

High levels of Calcium will also flocculate Bentonite.

The total hardness should be controlled below 400 mg/L and must not be allowed to rise above 600 mg/L.

Calculations and Reporting

Calcium Hardness is usually expressed in mg/l CaCo3.

Sources of Error

Can be difficult to see the end point of the test.

Calcium hardness can also be reported as mg/L CaCO3. Multiply this value by 2.5 to get the required value.


#1 Abdalqadr 2015-09-03 07:08

If it is not allowed to let calcium increase more than 600mg/l ?? but in salt saturated mud it is about 1600mg/l??????? ? How does that happen . please i need more details about the effect of calcium in drilling mud

Best Regards