Abstract: In accordance with the theory of grey correlation analy- sis,the well assemblage of flood development is taken into one system to establish the grey correlation.Taking the area of Gao 20-39 well as an example,the grey correlation theo- ry is used,in virtue of the dynamic data of oil producers and injectors,to analyze the connectivity of oil pay and the wa- terflood direction.With the purpose of optimizing the pro- duction fluid and compromising the planar relation,the method of grey correlation is suggested to be used in the a- nalysis on superiority of oil pays,and in the study on rela- tionship and variance pattern of production parameters of oil pays.