Perlite cement additive is a light, granular material made from crushed volcanic rock. Its primary use is to lower the density of cement slurries. It can be used at bottomhole temperatures (BHTs) between 40°C and 400°F (4°C and 204°C). Typical concentrations are 1 ft³ Perlite additive/1 ft³ cement or 2 ft³ Perlite additive/1 ft³ cement. Bentonite (Halliburton Gel) can be added to Perlite additive slurries to help prevent separation.
Perlite additive can provide the following benefits:
It exhibits excellent bridging properties that help control lost circulation.
Its insulating properties make it useful in thermal cementing compositions.
Slurries containing Perlite additive cost less per volume because this additive increases the per-sack yield of cement.