Drilling Fluid Contamination: Cement
Cement contamination occurs in every well drilled. It is contamination from calcium hydroxide which can result in increased pH, severe thickening and increased fluid loss of bentonite based mud systems (flocculation of the bentonite clay).
The severity of the problem will depend on the level of pre-treatment and thinner concentration in the mud.
In a highly treated Lignosulphonate system, the viscosity may actually drop as the clays go to an aggregated/flocculated state rather than a dispersed in flocculated state on the introduction of cement.
In polymer systems . . .