Abstract: After 40 years of development,Target layer,Maquanzi oil layer of Dongying formation in Ma-19 block is characterized by low production capacity and high water cut,therefore,remaining oil tapping of Ma-19 block becomes the development focus at present.Through the analysis of the geological characteristics of fine reservoir,residual oil is mainly distributed in the reservoir with low degree of area,and doubly controlled by the structure and sedimentary microfacies.Around the fault-edge,included angle,small fault blocks,and micro-high points,remaining oil is enriched.Besides,interchannel thin sand layer,distributary channel lateral margin,and the mid-upper part of positive rhythm reservoir are also enriched with remaining oil.