The identification and quantitative description of large pore pathways are of great significance to improve the measures of oil recovery at high water cut stages.Since the large pore pathways

usually developed in unconsolidated sandstone oil reservoirs at high water cut stage under the long-term injected waterscouring

can cause ineffective water cycle

and compromise the effect of water injection on recovery enhancement.Thus the study analyzed the seepage characteristics of high-velocity non-Darcy flow in the large pore pathways

to set up diagnostic criteria for large pore pathways according to the standards used to identify the high-velocity non-Darcy flow

and established an oil reservoir simulation system based on permeability

which changes with the pore volume expansion during scouring through water injection.And a quantitative description of the large pore pathways was given.Finally

the Ng6

3+4

development unit in the upper member of the west Gudong oilfield was selected for reservoir simulation to identify large pore pathways and to carry out the quantitative description of the pathways.The results show that the proportion of large pore pathways

mainly distributed around the injectors or between injectors and producers

is relatively small in the simulated reservoir.In conclusion

the diagnostic criteria of large pore pathways

taking into account of the injector-producer spacing

injection-production pressure difference and permeability

can be effectively applied to the oil reservoir simulation system and the resultant quantitative description of the large pore pathways is accurate.