Abstract: This paper took the Daqing oilfield as an example to ilustrate the importance of geological research of subdividing single sand beds in the late high water content period. The research of subdividing single sand beds will deepen the un-derstanding of the lateral and vertical distribution of reservoir and surplus oil, and therefore, will provide geological evidence for oilfield adjustment and tapping the potentialities.

Key words: Lale high water content period, Oilfield adjustment, Subdividing single sand bed, Reservoir ptoperty, Surplus oil distribution, Thick一bedded high effective well