[h=1]Funnel Viscosity[/h]
The funnel viscosity is time in second of drilling mud flowing through the Marsh Funnel Viscosity. The Marsh funnel is dimensioned so that the outflow time of one quart of freshwater (956 cc) at a temperature of 70 F +/- 5 F (21 C +/- 3 C) in 26 +/- 0.5 seconds.
Marsh Funnel
The funnel viscosity is time in second of drilling mud flowing through the Marsh Funnel Viscosity. The Marsh funnel is dimensioned so that the outflow time of one quart of freshwater (956 cc) at a temperature of 70 F +/- 5 F (21 C +/- 3 C) in 26 +/- 0.5 seconds.
Marsh Funnel
For all drilling mud, especially oil base mud, temperate always affects on the viscosity of base fluid. The base fluid will be less thick when the temperature increases. It means that the funnel viscosity will decrease.
The funnel viscosity measures at only one rate of shear but the temperature each time of measurement is not constant. This is the reason why the viscosity measured from the Marsh Funnel does not represent the true drilling mud viscosity. On the drilling rig, this measurement of the mud viscosity is still useful because it is a quick and simple test for observing trends of drilling mud.In order to use the funnel viscosity effectively, personnel must record the values frequently. Please remember that only single point of the funnel viscosity cannot tell you anything about a condition of drilling mud.