Abstract: In this paper, the useless reserves, sand body geometry, sedimentary rhythm and interconnecting feature of Ya'erxia area in Yumen field are investigated, along with detailed discussion of waterflooding characteristics of sand body shaped in diferent settings, by which relevant technological measures for formation fracturing and acid treatment are proposed. It is suggested that the waterflooding effect depends on heterogeneity of the sand bodies for most remained oil distribution in zones with low porosity and low permeability. Hence，in waterflood profile control， the productivity of major sand body should be controlled, considering those low-productivity sand bodies; in selection of properly fracturing horizons, low permeable zones should be fractured primarily in favor of even advancing of injected water. This result can be as a guide for improving development effect and EOR of Ya'erxia oilfield.

Key words: waterflooding, sedimentary rhythm, sweep efficiency, fracturing, water plugging