Functions of drilling mud:
Drilling mud is used to control subsurface pressures, lubricate the drill bit, stabilize the well bore, and carry the cuttings to the surface, among other functions.
Why solid cutting should be separated from drilling mud:
As the drill bit grinds rocks into drill cuttings, these cuttings become entrained in the mud flow and are carried to the surface. In order to return the mud to the recirculating mud system and to make the solids easier to handle, the solids must be separated from the mud.
How to separate solid cutting from drilling mud:
In order to recycle drilling mud, solids control equipments are used, usually 4 stage solids control equipment used.
1) First stage: Shale shaker
According to rig size, 1 or 2 or 3 sets shale shaker will be used at the first stage solids control separation.
Usually matched with API 60 or API40 shaker screen.
Cutting over 400µm will be separated in this stage.
2) Desander and desilter is used as the second and third stage separation. For better performance, GN recommend to bear a underflow shaker with desander / desilter.
Some clients may choose mud cleaner for these stages. It is a combination of shake shaker, desander and desilter. But more compact with less space.
For smaller size rigs (usually, under 750hp), mud treated by shale shaker and mud cleaner can be used for drilling.
3) In some condition, while drilling depth is big, and high standard mud request, decantering centrifuge will be used as forth stage separation. Finer solids can be separated.
4) For gas cut drilling mud, vacuum degasser, poor boy degasser and ingnition device will be used.
As one the leading solids control specialist worldwide, GN Solids Control offers complete line equipments for drilling mud recycling. GN is the only one China private supplier for drilling waste management. Visit GN website for more information or contact GN at sales@gnsolidscontrol.com