In oil and gas wells (and sometimes geothermal wells), a wiper plug is a device used mainly during cementing operations. Its job is to separate drilling mud and cement slurry, wipe the casing clean, and ensure that fluids don't contaminate each other.

The seal part of the wiper plug is critical — it makes sure:

The mud and cement stay separated properly,

The pressure holds up during the pump-down and setting,

No leaking or contamination happens during or after the cementing.

Key characteristics for the Cementing wiper plug conditions usually include:

1： High-pressure resistance (up to several thousand psi).

2： Temperature resistance.

3： Chemical resistance (because of exposure to drilling mud, spacers, cement slurry, and sometimes acid gases).

4： Elastic recovery to stay effective after deformation.

5： Low wear during long-distance pump-down.

Common materials used for these seals include HNBR/NBR/FKM.

Below is the picture of the wiper plug seals.