Abstract: Channel sand is the key contributor to oil production in Bohai Bay Basin, and reasonable understanding of distribution and connectivity of the channel sand is crucial to reservoir management and potential tapping. This paper started with the difference of production performance in BZ oil field, and previous geological understanding of reservoir A could not account for its dynamic behaviors. Detailed isochronal well correlation was then conducted to identify vertical heterogeneity caused by three-stage channels and two oil-water systems. Stratal slices were incorporated to confirm plane heterogeneity and recognize two typical stack patterns of channel sand, i e. stand-alone and bridge-linked channels. Integration of detailed isochronal well correlation, stratal slice and production data can provide reliable information for geological understanding of fluvial-reservoir development. New understanding of reservoir connectivity, distribution and oil-water distribution is efficient to guide the adjustment of development plan and well pattern.