Spacers for cementing
Spacers are any fluids other than cement slurry or mud, pumped ahead (preflush) or behind (postflush) the cement slurry.
Preflushes are used to:
- prevent contamination of cement slurry with mud
- improve mud displacement and mud cake removal.
Postflushes are used to prevent:
- the plug from spinning when it will be drilled out (cement on top)
- contamination with the fluid used for displacement.
The following guidelines shall be adhered to during the use of spacers: