In one aspect, a method of estimating fluid flow contribution from each producing zone of multi-zone production well is provided, which method may include: defining a wellhead pressure; determining a first inflow performance relation (IPR1) between pressure and fluid inflow rate at a first producing zone and a second inflow performance relation (IPR2) between pressure and fluid inflow rate at a second producing zone; determining a combined performance relation (IPRc) between pressure and fluid inflow rate at a commingle point; defining an initial fluid flow rate into the well from the first zone and an initial fluid flow rate from the second zone; generating a first fluid lift performance relation (TPR1) between pressure and total fluid flow corresponding to the commingle point using the initial fluid flow rates from the first and second production zones and at least one fluid property; and determining contribution of the fluid from the first zone and the second zone at the commingle point using IPRc and TPR1.