Development of and Study on a High Temperature Suspension Stabilizer for Oil Well Cement Slurries

A high temperature suspension stabilizer has been developed to deal with sedimentation of oil well cement slurries at elevated temperatures. The viscosifying property of the suspension stabilizer at high temperatures was tested and the mechanisms of viscosifying at high temperatures analyzed. The effects of the high temperature suspension stabilizer on several properties of cement slurries, such as sedimentation stability, rheology, thickening curve and compressive strength of the set cement, were evaluated through laboratory experiment. It was found that the high temperature suspension stabilizer increases the viscosity of the cement slurry at elevated temperatures through hydrophobic association between molecules. The density difference of the set cement can be controlled within±0.025 g/cm³ by the addition of the stabilizer, indicating that the stabilizer has excellent sedimentation prevention property. The consistency coefficient of the cement slurry was maintained in a narrow range by the stabilizer, between 4.441 Pa·sⁿ and 5.760 Pa·sⁿ, and this made the consistency of the slurry stable. The strength of the set cement, which was almost not affected by the use of the suspension stabilizer, satisfied the needs of well cementing job.