Study on Chang 2 reservoir heterogeneity in Zhidan area

Chang 2 reservoir of Zhidan area belongs to delta front subfacies depositional system,with undeveloped faults and mainly developed nose-like structure.The research results show that Chang 2 reservoir is of stronger heterogeneity overall,lamination factor and sandstone density of Chang 22 is relatively good.As the connectivity and continuity of internal sand bodies among sub-layers is better,heterogeneity of Chang 22 is weaker than that of Chang 21 and Chang23.Plane heterogeneity is closely related with sand body distribution and communication manner.The distribution direction of zones with high porosity,high permeability agrees with palaeocurrent direction.Reservoir interlayer is well developed,with more sand lamina and less argillaceous interlayer,and mainly develops intergranular pore and dissolution pore.