Decanter centrifuge for drilling mud solids control - Soil and Groundwater
Decanter centrifuge is used as the 4th phase solids control equipment after shaker, desander and desilter. The centrifuge suck the mud from the compartment receiving the discharge from the desilters and mud cleaners, and the returned stream is directed to the next compartment downstream. The use of decanter centrifuge with the drilling mud is (1) removal ﬁne solids from unweighted ﬂuids (2) selection separation of colloidal and ultra-ﬁne solids from weighted ﬂuids to improve their ﬂow properties.
The Use of Decanter Centrifuges with Unweighted Drilling Fluids
GNLW series decanter centrifuges are specially designed for the drilling mud solids control. The effective centrifuging and fine drilled solids separation can remove significant quantities of inseparatable solids. This significantly reduces the tranditional dilution requirements and drilling waste volume for disposal.
When centrifuging the unweighted drilling mud, keep in mind the following:
- Oerate the centrifuge with High G force as the solids loads are low
- Adjust the weir to a deep pool to maximized solids separation
- Control a smaller mud feed rate to increase residence time
- Operate centrifuges in parallel, not in series if multiple centrifuges are required.
The Use of Decanter Centrifuges with Weighted Drilling Fluids
With the unavoidably higher solids content of weighted muds, the increase of gel strengths and viscosities, as well as the degradation of ﬁlter cake quality associated with the diminution of particle size with time, can become a serious problem. The problem is caused by the increasing concentration of colloidal and near-colloidal particles that are too ﬁne to be separated from the base ﬂuid. Centrifuges are used to selectively remove these ﬁne solids.
With high solids content of weighted fluids, torque is a problem when processing it, the following is some advice when operating the centrifuges.
- Increase pond depth
- Reduce in rpm or run a higher conveyor differential
- Process the mud at a reduced feed rate