A minimum volume prediction of spacer based on turbulent dispersion theory: Model and example

During cementing operations involving cement slurry contamination,problems often occur due to the inaccurate calculation of the space fluid volume.This study,based on the turbulent dispersion theory,developed a minimum volume calculation model of spacer fluid to prevent cement slurry contamination.This model was used to analyze influence factors and practical calculations.The results indicated that the minimum volume of spacer fluid increase with the eccentricity of casing and injection rate and decrease with the density of cement slurry.Additionally,the better rheological properties of the cement slurry and spacer fluid would increase the volume of the spacer fluid.Furthermore,this model fitted actual field data better than other heat calculation models.