Dec 30, 2013
In the solids control system, there are usually several kinds of main equipment, including mud tank, shale shaker, vacuum degasser, desander, desilter, drilling fluid decanter centrifuge. Shale shaker is used to separate the big solids with diameter above 75μm, and 45~74μm for desander, and 15~44μm for desilter. Sometimes desander & desilter are combined as high efficient mud cleaner.
The drilling fluid desilter is the third stage equipment in the whole drilling mud system, at the same time, it is an important device, too. Let's see some common problems and solutions for that .
(1) Repeated plugging of Apex in all cones.
(2) One or more cones plugging while others are working normally.
(3) Cones are loosing whole mud in stream.
(4) Solids content in cone overflow continues to increase over time.
(5) The underflow discharge is very dry.
(6) Hydrocyclones leak between the cone nut and body, but no fluid is coming out of the bottom.
(1) Too small of underflow opening.
(2) Plugged at feed inlet or outlet.
(3) Backflow from overflow manifold, or centrifugal pump impeller worn out or too small,
(4) Drilling through hydratable clays will cause increased viscosity.
(5) Strong vacuum in manifold discharge line.
(6) The apex cone nut is tightened too much which does not allow fluid or solids to exit the hydrocyclones.
(1) Increase apex opening size if possible. If this does not help try a finer mesh screen on the shaker to remove more of the solids before they enter the hydrocyclones.
(2) Remove apex nut and clean out blockage. If this does not help, remove the entire cone to check for blockage at the inlet.
(3) Caused by a plugged cone inlet, clean out the inlet. Check the pressure at the inlet manifold. Low pressure indicates decreased head from the pump, then remove cone and clean.
(4) Cone separation efficiency decreases as viscosity increases, dilute the mud to decrease viscosity if possible.
(5) Usually it occurs since discharge line drops into pit. Enlarge the discharge line or install anti-siphon tank.
(6) Hydrocyclone apex nuts should be only hand tightened. Cones should be checked frequently to ensure that apex nut is not worn out causing rope discharge.
