Special Cement Slurry Design Consideration for High Temperature High Pressure Gas Well

Abstract

This study explores special cement slurry design consideration for high temperature and pressure gas wells. Seven different materials were used as additives which includes: fresh water, dyckerhoff, silica flour, antifoam, extender, fluid loss, dispersant, retarder, anti-settling agent, gas control agent, dry viscosifier, potassium chloride and accelerator. Four recipes were prepared using these additives in different mixtures. Recipe four has all the additives. A series of flow tests was performed using an advanced shear-stress/shear strain controlled rheometer. 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. The four recipes were applied in 10 cases. Among the four different recipes tested for all the 10 cases, recipe 1 gave a regression value of 52.19% correctness, 65.43% correctness for recipe 2, 23.72% for recipe 3 and 96.58% correctness for recipe 4. Recipe 4 has the best regression values for both temperature vs transit time and pressure vs transit time this can be accounted for the presence of both silica flour and potassium chloride salt.