In the first part of this study the effect of free water on fluid migration potential is tested for different cement slurries using standard API G-class quality tests. Static gel strength analyser is also used to measure the static gel strength of cement slurries. Three different class G type cement samples were tested according to their free fluid values which are 2.5%, 5%, 3.12% respectively, and it is found that A-type cement, with lowest free fluid content, has the lowest potential for fluid migration. On the other hand, viscosity and gel strength values of cement slurries were determined at six different shear rates. At the same time, cement slurries were characterised by different rheological models and it was observed that Casson model best described the rheological properties of cement slurries.