Abstract: Wells drilled in the Block SN have high bottom hole temperature under static conditions, and the gas zones are very active. Prevention of well kick and lost circulation during drilling is quite difficult. Latex anti-channeling cement slurry alone has been used in the past in well cementing, but it didn't work well. Liquid silica latex, as a nanometer anti-channeling agent, has active SiO₂ that will take part in the hydration reaction of cement. It thus helps increase the strength, reduce the elastic modulus and permeability of set cement. By optimizing the amount of silica used and the ratio of coarse particle over fine particle silica, a high temperature antichanneling liquid silica latex cement slurry was developed. This cement slurry had filter loss less than 50 mL, a right-angle thickening curve, an SPN less than 1, good anti-channeling performance and settling stability. SEM and XRD analyses demonstrated that a dense set cement can be acquired. Tobermorite and xonotlite, instead of Ca(OH)₂, were found in the hydrated cement, and this results in a stable strength of the set cement at elevated temperature. High pressure gas zones in wells drilled in Block SN have been effectively cemented with this anti-channeling liquid silica latex cement slurry.