Perlite is an inert volcanic glass, consisting of approximately 75% silica which is expanded by heat to form a cellular product of extremely low bulk weight.
Perlite provides low-density cement with reduced permeability and
better insulating properties than conventionally extended cements.
Perlite additive can be used at bottomhole temperatures (BHTs) between 40°F and 400°F
Applications for Perlite
In oilwell cementing perlite is mainly used as an extender for Portland Cement. Perlite reduces the density which enable weak zones to be successfully cemented and isolated. Perlite can be used also as an strength enhancer.
Perlite help control lost circulation thanks to its excellent bridging properties.
Perlite in expanded form is also used as a lightweight agent.The final density of the product is dependent on external pressure and on how many pore spaces remain closed. As the pore spaces collapse and take on water the density of the slurry will increase.