Hydroxypropylmethylcellulose as a Free Water and Settling Control Agent in Oil Well Cement Slurry

Abstract

Free water and sedimentation of particles are considered as severe problems for cementing operation. The sedimentation of particles alters the density of designed cement slurry and reduces hydrostatic pressure that becomes the cause of gas migration. Different additives and polymers have been used for prevention of free water and sedimentation. However, the mineralogy, chemical reaction, and increasing temperature affect the properties of additives and polymers. At high temperature, polymers suffer high thermal thinning problem and loss of viscosity that become incapable of controlling free water. This study presents hydroxypropylmethylcellulose (HPMC) polymer that works as viscosifying agent at high temperature. The inclusion of HPMC polymer in cement slurry eliminates the free water separation and sedimentation of solid particles at high temperature. Laboratory experiments were performed to determine the viscosity of 2 wt% of HPMC solution at various temperatures 30–100 °C. Further API properties of HPMC-based cement slurries were determined in terms of rheology, free water, and fluid loss with other additives at 90 °C. It was observed that HPMC polymer was stable at high temperature. In cement slurry, HPMC polymer completely prevents the free water separation and sedimentation of solid particles and decreases the fluid loss through cement slurry at high temperature.