Abstract: Based on similarity theory and considered non-Darcy character in low permeability porous media, the theory about simulation experiments on the oil-water two-phase flows were researched. The dimensionless forms of controlled equations about oil-water two-phase flows were derived by the equation analysis method; and the similarity criterion about the waterflooding simulation experiment in low permeability cores was obtained. The dimensionless controlled equations were solved by the IMPES method; so the numerical simulator including similarity criterion was obtained. Through sensitivity analysis, the influence degree of every similarity criterion on experimental results was calculated and verified by waterflooding experimental results of low permeability cores. Results show that the similarity criterion whose sensitive factor is larger has greater influence on the experimental result. Contrarily, it has little influence on the experimental result. Therefore, when the physical model is designed and not all similarity criterions between the prototype and the model are equal, the larger similarity criterion should be given priority to be equal.

Key words: similarity criteria, low permeability, non-Darcy flow, waterflooding, physical simulation