Study On The Reservoir Property Of The Chang4+5,Chang6₁ In The Area Of Majiashan-Xiaojianzi

Based on the former's research and effectively utilizing the first data of core observation,well logging,geological borehole log and the techniques of modern laboratory analysis, the Chang4+5,Chang6₁ oil-bearing formation zone of Yanchang formation reservoir, Upper Triassic of the Majiashan-Xiaojianzi area in Ordos Basin, has been analyzed synthetically.In the reservoir, the main rock types are Feldspar and Feldspar Lithic sandstone; the main Diagenesis are Consolidation,Cementation,Metasomatism and Dissolution; the Diagenetic stages can be classified into later A-substage to former B-substage of later Diagenesis; the crack caused by squeezing action during the stage of Diagenesis plays an important role.Macroporosity,Microporosity,Mixed and densification are the most commen pore types in the area; Lamina sew,Crack,Intergranular residual porosity and Intergranular dissolution porosity are main reservoir space, Lamina sews caused by Sedimentary play an important role for oil and gas gathering; the plane distributional characteristics of Porosity and Permeability are controlled by sand development and Micro Sedimentary Facies.Macroscopic heterogeneity of the reservoir is mainly controlled by Sedimentary Facies and Diagenesis, while Pore structure of the sandstone is a main reason resulting in the Microscopic heterogeneity of the reservoir. The result of real-sandstone micro-model experimentation indicated that there are two types of oil displacement: crack one and pore-crack one, the later efficiency of oil displacement is better than the former.Based on the study, the reservoirs are classified that the Chang4+5₂ is the favorable reservoir, Chang6₁ is inferior, Chang4+5₁ is worse than the other ones in the region, and predicted prospecting advantageous regions.