Abstract: Regarding the problems of poorer experiment effect than the designed one due to plugging in deep layers at the initial binary combination injection stage into the conglomerate reservoirs in the lower Karamay formation in District Qizhong of Karamay oilfield, Xinjiang, the microscopic distribution and genesis of the plugging are studied using electron-probe X-ray microanalyzer. The result shows that the binary combination system with excessive molecular weight and mass concentration matches poorly with the reservoir and mainly occurs in complex pores and pore throat where clay minerals accumulate, which results in poor physical properties of the conglomerate reservoir and poor mobility during the oil displacement process. Large amount of kaolinite in the conglomerate reservoir tends to drop off at relatively high injection rate and reacts with the injected binary combination system, resulting in the plugging of reservoir pores. Based on the above understanding, experimental study on physical plugging removal is carried out. Typical natural cores with different physical properties are selected, and binary combination systems with high, moderate and low molecular weights and mass concentrations are injected in to the cores. Resistance coefficient and residual resistance coefficient are calculated under steady pressure and then the mobility could be determined. The result shows that physical plugging removal in the conglomerate reservoir has a permeability limit that the plugging in moderate and high permeability reservoirs (>50 mD) could be effectively relieved by gradually decreasing the molar weight and mass concentration of the binary combination system, but it doesn’t work for the plugging in low permeability reservoirs (<50 mD) . After field formula adjustment, injection pressure decreases steadily, liquid production increases and plugging is effectively relieved. It is predicted that the binary combination flooding in the conglomerate reservoir could improve recovery factor by 15% in the study area