Abstract: In the Tahe Oil Field, vuggy reservoirs with active bottom water and well-developed high-angle fractures are explored by means of overall acidification. There is little potential after flooding. Through the identification and classification of dense segment, the remaining potential of reservoir is evaluated by means of the water drive curve of sandstone reservoir. Taking use of the barrier effect of dense segment, return acidification practice is carried out successfully in the field, and succeeds in increasing oil production.