Establishment of inflow performance relationship of horizontal wells in low-permeability reservoir

The productivity equations in steady fluid flow and oil-gas two-phase flow with solution gas drive of horizontal wells in low-permeability reservoirs were established by equivalent flowing resistance method.And the dimensionless inflow performance relationship of horizontal wells was given.The equations of inflow performance relationship are simple and clear,and correspond with Wiggins equations.The results show that the flow in middle and high permeability reservoirs is only a special case of flow in low-permeability reservoirs when the starting pressure gradient equals to zero.The productivity for horizontal wells in low-permeability reservoirs decreases with the starting pressure gradient increasing.And the productivity for horizontal wells increases evidently with the length of horizontal well increasing.