1. Check that the narrow discharge tube at the base of the funnel is clear.
2. Hold the Marsh Funnel upright, place a finger over the discharge tube, and use a mud cup to fill the funnel until level with the wire-mesh screen, using the wire-mesh screen to remove larger particles that might block the narrow discharge tube.
3. Hold the Marsh Funnel above an empty mud cup, remove the finger covering the discharge tube, and record the time to fill the mud cup with 1 quart (946 ml) mud.
4. Record the Funnel Viscosity as the time taken in seconds. The mud temperature is often recorded simultaneously since temperature changes often account for viscosity changes.
5. Wash the Marsh Funnel after use, ensuring the narrow discharge tube is clean.
Calibration checks should be made periodically, using the procedure detailed above, by filling the Marsh Funnel with fresh water and recording the time to discharge 1 quart of water, which should take 26 seconds ± 0.5 seconds for water at 21°C ± 3°C.
Related Papers For Marsh Funnel Viscosity Test Procedure
- The Marsh Funnel and Drilling Fluid Viscosity: A New Equation for Field Use
- Apparent Viscosity Prediction of Water-Based Muds Using Empirical Correlation and an Artiﬁcial Neural Network
Video Explaining How To Use March Funnel
The Marsh Funnel viscosity represents the time in seconds that it takes a quart of ﬂuid (1500 mL) to ﬂow out of a cone via a short cylinder into a graduated cup. Marsh funnel viscosity directly indicates the overall viscosity of drilling mud. The standard Marsh funnel viscosity of water is approximately 26 s.