Objective Multi-thermal fluid stimulation technology uses hot water composite flue gas to heat and reduce viscosity of heavy oil. Its composition is mainly hot water, N₂ and CO₂. It is an economical and effective technology for the offshore heavy oil development. But with the increase of the number of channeling rounds, the problem of gas channeling has been exposed, that is, non-condensate gases such as N₂ and CO₂ can easily break through to peripheral production wells, resulting in the impact of electric pump gas lock on production.

Methods Taking the NB oil field as the research object, the visualization experiment method was adopted to study the control strategy of preventing gas channeling.

Results The QGQ-4 blocking system suitable for the oil field was selected. The optimal injection parameters were optimized for the concentration of 0.4 wt%, the foam dryness was over 60%, and the ground prefabricated foam injection method was adopted. Compared with simple multi-thermal fluid flooding, foam-assisted multi-thermal fluid flooding can improve reservoir sweep, effectively block gas channeling, and increase plane sweep coefficient by 37%.

Conclusions After the field application of the research results, the peak daily oil at the beginning of the beneficiary well increased to 1.5 times before adopting the measures, the daily oil production increased from 50.3 m³ to 75.7 m³ after adopting the measures, and a good increase in production was achieved.