Abstract: Petrobras established inflow performance relationships of three-phase for imperfect wells. On the basis, taking the influence of well damage to inflow performance relationships into account, this paper derived a mathematical model of three-phase inflow performance relationships for damaged wells and improved the theoretical system of three-phase inflow performance. By adopting the two-phase flow efficiency to describe the influence of well imperfection on deliverability, the maximum production of imperfect well can be calculated. Examples show that well imperfection will affect deliverability in varying degrees. The three-phase inflow performance under different flow efficiency can be predicted according to the method presented in this paper.