Abstract: In view of the existing water cone variation formulas of directional wells in heavy oil and bottom water reservoirs, the changes of reservoir physical properties caused by long term large fluid volume scour have not been considered, which lead to the large sweep volume of water flooding, pessimistic understanding of remaining oil and poor reserve production degree and so on. In order to describe more accurately the variation law of water cone and the distribution of remaining oil between wells in high water cut stage, the variation law of reservoir physical property under long term large fluid volume scour is considered synthetically. The equivalent percolation resistance is used to characterize the permeability of the reservoir inside and outside the water cone, and the equation of numerical variation of heavy oil and bottom water reservoir considering physical property time variation is derived. Through the analysis of practical examples, it is found that the influence of reservoir physical property time variation on water cone is very significant. Under the same water cone width, the water cone height calculated by the water cone formula, which does not take account of the time-varying physical properties, is reduced by 46.3%. Compared with the results of log interpretation, the relative error is only 5.3%. The field pilot test proves the reliability of the water cone change formula of the directional well in the bottom water reservoir considering the time variation of physical properties. This reseach provides technical support for accurate description of water cone change and residual oil distribution law of heavy oil bottom water reservoir in high water cut stage under long term large liquid volume scour.

Key words: heavy oil and bottom water reservoir, high multiple water drive, physical property time-varying, water cone variation, field application