Cementing Additives

Class C fly ash (high lime, >20% CaO) has both cementitious and pozzolanic properties and sets without activator. Class F fly ash (low lime, <10% CaO) is primarily pozzolanic and requires Ca(OH)₂ from cement hydration or lime addition to react. Both are used as extenders in well cementing; Class F is more common in oilfield cementing for density reduction and improved slurry rheology.

METACEM is a highly reactive alumino-silicate pozzolan that reacts rapidly with Ca(OH)₂ liberated during cement hydration to form additional C-S-H and calcium aluminate silicate hydrates. This reduces the Ca(OH)₂ content (vulnerable to carbonation and leaching), improves compressive strength, reduces permeability, and enhances resistance to chemical attack in CO₂-containing well environments.

Slag (GGBFS) is a latent hydraulic binder that reacts slowly with water when activated by Ca(OH)₂ or alkalis. In well cementing, slag is particularly useful in low-temperature environments (below 60°C) where it provides excellent long-term strength development, very low permeability, and exceptional resistance to sulphate attack and chloride-rich formation waters.

Microsilica (silica fume) is an amorphous, ultra-fine material with particle sizes typically 0.1–0.3µm — approximately 100 times finer than silica flour. This extreme fineness gives it much higher surface area and pozzolanic reactivity, enabling faster strength development, lower permeability, and superior performance at lower dosages compared to crystalline silica flour.

API 10A (Specification for Cements and Materials for Well Cementing) governs quality requirements for Portland cement and cementing additives used in oil and gas well cementing. Our cementing additives portfolio is designed and tested to meet API 10A requirements, ensuring consistent performance in oilfield applications.