Definition - What does Settlement Tank mean?
A settlement tank is a compartment that allows solid content such as sand and cuttings to precipitate and sink to the bottom.
The settlement tank has an inlet to allow the drilling fluid into the chamber where it sits before flowing to the next tank. The purpose of the tank is to allow the fluid to rest for a while as the waste material settles out. It is an extremely important process that allows the drilling fluid to be reused by circulating it back into the borehole.
A settlement tank is also called a settling tank or a sand trap.
Trenchlesspedia explains Settlement Tank
The circulated drilling fluid is first passed through the shale shaker before entering the settlement tank. The received fluid is not stirred and allowed to rest.
The tank usually has a discharge control that can be quickly and easily opened and closed allowing the solids to be dumped without losing the whole mud.
Since there is a possibility of the weighting agent barite also settling in the tank, a provision for bypassing the undersize screen discharge slurry directly to the next processing compartment is advisable.