Abstract: The macro pores developed in the long term water flooding reservoir decrease the sweeping efficiency. the indoor physical simulation experiments on the forming mechanics and the affecting factors of the macro pores are introduced in the paper; aiming at the drawbacks of the indoor physical simulation experiments; the ways of qualitatively and quantitatively identifying the macro pores by means of well test, logging, and core analysis and so on are mainly introduced; the present major problems analyzed, and it is proposed that, based on the theories of oil reservoir engineering, together with the advanced logging technology and interpretation method, it is workable to qualitatively and quantitatively identify the macro pores. some research conceptions are proposed. Accurately identifying and describing the macro pores in unconsolidated sand stone oil reservoir and calculating relevant parameters are not only helpful to recognize the reservoir more intensively, guide sand prevention of the oil wells and regulate the working system of the oil wells, but also will provide technical foundation for the selection of the blocking agents and technological design of the shutoff in the middle and latter stage of the oil development.

Key words: unconsolidated sand stone oil reservoir, macro pores, permeability, tracer, flow through porous media