Abstract: Asphaltene in viscous oil components constitute the majority in Kelamayi Oilfield, one suitable microbien is selected to effectively treat viscous oil in Kelamayi by means of indoor bacteria research method and the bacteria can remarkably decrease asphaltene of viscous oil.Field test effect of microbial huff and puff showed that the treats are 100% effective so that six wells produce more oil and the cumulative incremental oil is 936.883t, acquiring obvious economic benefits. The technology provides a simple and friendly new method to environment to enhance oil recovery for Xinjiang Oilfield after viscous oil steam huff and puff.

Key words: microbial huff and puff, viscous oil, asphaltene, viscosity decreasing, field test