Effect of Supplementary Cementitious Materials on Rheology of Oil Well Cement Slurries

Abstract

Abstract This study explores the effects of supplementary cementitious materials (SCMs) on the rheological properties of oil well cement slurries. Four different mineral admixtures including metakaolin (MK), silica fume (SF), rice husk ash (RHA), and class F fly ash (FA) were used as partial replacement for API class G oil well cement. A new generation polycarboxylate-based high-range water reducing admixture was used to improve the fluidity of slurries. A series of flow tests was performed using an advanced shear-stress/shear strain controlled rheometer at three different temperatures, namely 23, 45, and 60°C. Rheological properties of cement slurries were calculated from the resulting flow curves using the Bingham plastic model and the Herschel–Bulkley’s model. Changes in shear stress–shear rate relationships, yield stress, plastic viscosity, and shear thinning/thickening behavior were found to be related to temperature and the type and dosage of supplementary cementitious material. Among the four different mineral admixtures tested, low calcium fly ash was found to achieve most suitable yield stress and plastic viscosity values.