Abstract: Accumulation may be divided into three periods based on inclusion analysis:E₃d³-E₃d²,the end of E₃d and N₁g-N₂m.Pool-forming is mainly controlled by trap type,fault activity and growth of cap and reservoir,and the pattern of pool-forming is established.There are different pool-forming stages for different structural zones,resulting in the heterogeneity of oil-and-gas distribution both laterally and vertically.The mid-deep formation in Kuitai area and the slope of Yannan area are the major potential region.