Abstract: The sandstone-bottom water reservoirs can be widely found in China，a critical problem for developing the reservoir is bottom water coning.Inter-bedded stratum can constraint this phenomenon with a satisfactory effect.However，due to the complexity of the origin of inter-bedded stratum，there′s no uniform research model of it.Aiming at this issue，it is pointed out that according to the some parameters of inter-bedded stratum such as area，thickness，permeability and shale content，various inter-bedded strata can be approximated as non-inter-bedded model，permeable model，small area impermeable model and impermeable model.The field exploration effect is not good in both non-inter-bedded models in which the bottom water coning speed is high and large area impermeable model in which bottom water coning is totally constrained.On contrast，field exploration effect is good in permeable model in which bottom water is transformed into secondary edge water and secondary bottom water and small area impermeable model in which bottom water is transformed into secondary edge water.In the non-inter-bedded model，the area far from wellbore contains enormous remaining oil which can be recovered by improving the well pattern.Permeable model enjoys a good effect of exploration in which little remaining oil can be found.Under the small area impermeable stratum，“roof”oil will form which can be a research direction in late-stage development.Much remaining oil can be formed between the up layer and down layer in the large area impermeable interbeds which is the highlight of late-stage exploration.

Key words: sandstone reservoir, bottom water reservoir, inter-bedded stratum, reservoir development, oil and water movement, remaining oil