Lightweight oil well cement slurry modified with vermiculite and colloidal silicon

This paper present a study on the influence of both vermiculite and colloidal silicon on the physical, mechanical and microstructural properties of a lightweight oil well cement slurry. Vermiculite was incorporated with Class G Portland Cement at a rate of 5, 7 and 9% and colloidal silicon at a rate of 0.5, 1.0 and 1.5%. The density, settling test and compressive strength of the blended slurries were determined in accordance with API standards. The microstructure characteristics of the hardened samples were investigated by scanning electron microscope (SEM). The experimental results were analyzed using a statistical method based on Analysis of Variance (ANOVA) to identify the influence of the vermiculite, colloidal silicon and calcium chloride. The results revealed that the compressive strength is strongly related to both the concentrations of vermiculite and colloidal silicon, with values up to 10 MPa and that the use of vermiculite as an extender for oil well cement slurries allowed for very stable slurries, with high water/cement ratio and low densities (12.5 lb/Gal).