Sustainable cement blends for oil well steam injection using rice husk ash

This study involves applying Rice Husk Ash (RHA), a sustainable source of silica, as an alternative to the use of Silica Flour (SF) in well cementing prior to steam injection. Slurries were prepared containing 20% and 30% BWOC of RHA along with standard slurries without additives and with 40% BWOC of SF. Behavior of the slurries was investigated using X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and uniaxial compressive strength assays. The results indicate that adding 30% of RHA and silica flour makes it possible to maintain compressive strength in the cement, and presents C–S–H crystalline phases rich in silica (Xonotlite and Tobermorite), as demonstrated by XRD, TGA and SEM. That makes it more attractive than standard slurry with 20% of RHA. That substitution makes slurry RHA competitive with SF and interesting for industry, due to its high content of renewable silica along with a low production cost.