Based on Kelvin-Helmholtz stability criteria for stratified flow in literature

the new criteria of transition from stratified flow to non-stratified flow for gas-liquid flow in horizontal wellbore was developed

in which the influence of wall inflow was considered.Experimental researches and prediction calculations were done in order to analyze how much wall inflow affected transition conditions.The volumetric flow rate per unit pipe length was small

and the influence of wall inflow might be neglected for the flow pattern prediction of local segment unit

but could not be neglected for the flow pattern prediction of downstream segments unit because it changed the value of flow parameters of downstream segments.Therefore

the transition criteria used for normal pipe flow might be directly used for gas-liquid flow in horizontal perforated pipe.But flow pattern prediction calculations should be done segment by segment in downstream units.