As a new type of foam stabilizing material

nano-particles can significantly improve the stability of foam. The research and application of nano-particles have been paid much attention by petroleum researchers. Considering the demand of water plugging technology in Bohai Oilfield

and guided by the theory of physical chemistry

polymer materials and reservoir engineering

we studied the evaluation of basic performance and the physical simulation of water plugging effect of nano-particle nitrogen foam system according to the geological characteristics and fluids of typical reservoirs in Bohai by technical means such as instrument detection

chemical analysis and physical simulation. The results showed that

when the concentration of foaming agent（PO-FASD） and stabilizer（SiO

2

nano-particle AEROSIL380） were about 0.3 %

the foaming agent and foam stabilizer could form the three phase foam system with nitrogen in excellent performance. With the increase of the reservoir permeability gradation

the effect of water flooding development got worse

and the effect of foam plugging and increasing oil increased. While with the increase of the water flooding recovery

the effects of foam plugging and oil increasing effect were improved. However

if the viscosity of crude oil increased

the effects of foam plugging and oil increasing effect would get worse. Thus

we could find that the three-phase foam system has good plugging and liquid flow steering ability

especially suitable for high water cut reservoir high permeability layer water plugging.