Dewatering Water-Based Drilling Fluids

Processing drilling fluid in sensitive environments

Most dewatering applications occur in areas of zero discharge, where closed-loop systems are required. In closed-loop systems, dewatering is the final step in mud processing, following the separation of liquid from solids provided by the shale shakers, hydrocyclones, and centrifuges.

Dewatering services may also be required when there is a high cost or potential future liability associated with fluid and/or solids disposal. Finally, dewatering may also be performed when the active mud system’s volume needs to be reduced. This is done for a cement job, a well change, or displacement.

In a dewatering project, the drilling fluid will be processed from the mud system, and the resulting solids will be discharged for disposal, bioremediation, or land farming. The clean fluid can be stored in a frac tank on-site for later use on the existing well or may be brought to a new well for drillout. In certain instances, the clean fluid may be disposed to ground, if allowed. Whichever situation is encountered, FluidControl dewatering service reduces mud dilution, mud costs, and unwanted liquid waste on the location and produces clean, reusable water.

The dewatering process uses a precisely regulated polymer feed, which is used to coagulate and flocculate the solids, allowing for easy removal by the centrifuge. The dewatering skid (typically a DWU-150) uses two polymer tanks (one for backup) to ensure that no downtime is realized while mixing the polymer. The centrifuge feed pump takes suction from the active mud system, moving the fluid through the injection manifold to the dewatering centrifuge for processing. The manifold system controls the amount of polymer and, if necessary, pH reducer that is injected into the fluid being processed.