A cement slurry may be separated from a drilling mud in a wellbore by introducing into the wellbore an aqueous fluid having a weighting agent, a hydratable gellant powder having a particle size distribution from about 150 to about 300 mesh; and a suspension agent of particulates of a resin encapsulated hydratable polymeric viscosifying agent, the suspension agent having a particle size distribution such that at least 90% of the particulates are retained on a 20 mesh screen and 100% of the particulates are retained on a 6 mesh screen. The weighting agent may be suspended in the viscous fluid by hydrating the hydratable gellant powder. At higher temperatures and after degradation of the hydrated gellant, the weighting agent remains suspended by degrading the resin of the suspension agent and releasing the hydratable polymeric viscosifying agent into the wellbore.