Cementing gas channeling is an important problem that affects the quality of cementing, and the selection of cementing materials has a great impact on whether gas channeling occurs. Organic cementing materials such as conventional latex have high formation sensitivity and many restrictions on the use conditions, while inorganic cementing materials such as silica have good comprehensive performance and have good prospects for use. With the development of ultra-deep Wells, there is an urgent need to study the anti-channeling emulsion of nanometer silica due to the problem of high temperature anti-channeling.

The basic properties and anti-gas channeling properties of nano-silica slurry system at 120℃ and 180℃ were compared by different particle sizes of silica emulsions, and microscopic SEM scanning analysis was carried out.

The experimental results show that the basic performance of nano-silica slurry is good. With the increase of nano-silica emulsion content, the API water loss decreases significantly to 35mL, the SPN value decreases significantly to less than 1, the permeability of cement is reduced to 90%, and the compressive strength remains unchanged at 28d. The bonding strength between the cement and the wall is increased from 0MPa to 4MPa, and the development time of static gelling strength is reduced to 6min. When the dosage of 15% nano silicon emulsion is above, the properties of cement stone remain stable for a long time.

The 1% plus amount of complexing agent DTPA and 2% plus amount of PEG200 can effectively solve the thixotropic problem of cement slurry, and the 1%-1.2% plus amount of DTPA can effectively solve the incompatibility problem of nano silicon cement slurry and retarder. The application in cementing field shows that the nano-silicon cement slurry system can effectively solve the problem of gas channeling and meet the needs of the field.