A method for maintaining a well production model (202, 302) of a well, comprising: receiving (204,206) an update to a parameter (304, 306, 308, 310, 312) of the well production model; and updating the well production model (202, 302) based on the received updated parameter (304, 306, 308, 310, 312); splitting (210, 506, 508) the well production model (202, 302) into at least two submodels after updating the well production model (202, 302), characterized in that the splitting of the well production model into submodels comprises: when a Bottom Hole Pressure of the well is unknown, splitting the well production model into a surface submodel and a combination of a Vertical Lift Performance submodel, which extends from the Bottom Hole Pressure to a tubing head pressure, and an Inflow Performance Relationship submodel, which extends from a reservoir pressure to a Bottom Hole Pressure; and when the Bottom Hole Pressure of the well is known, splitting the model into a surface submodel, a Vertical Lift Performance submodel, which extends from the Bottom Hole Pressure to a tubing head pressure, and an Inflow Performance Relationship submodel, which extends from a reservoir pressure to a Bottom Hole Pressure, and that the method further comprises inducing a computer system to: run the submodels after the splitting (506, 508) to obtain submodel results in the form of estimated well parameters; determine (212, 512), in a determination process, that the submodel results obtained by running at least one of the submodels match or do not match by comparing the submodel results with the results obtained by at least one of the other submodels, or with liquid production rates; if the results match: save the model and terminate the determination process; and if the results do not match: identify (212, 514) which of the submodels yield results that do not match the results of the other submodels, or do not match the liquid production rates, and terminate the determination process; and calibrate the submodels that yield results that do not match the results of the other submodels, or the submodels that do not match the liquid production rates, and that the model is employed to adjust physical parameters of the well. receiving (204,206) an update to a parameter (304, 306, 308, 310, 312) of the well production model; and updating the well production model (202, 302) based on the received updated parameter (304, 306, 308, 310, 312); splitting (210, 506, 508) the well production model (202, 302) into at least two submodels after updating the well production model (202, 302), when a Bottom Hole Pressure of the well is unknown, splitting the well production model into a surface submodel and a combination of a Vertical Lift Performance submodel, which extends from the Bottom Hole Pressure to a tubing head pressure, and an Inflow Performance Relationship submodel, which extends from a reservoir pressure to a Bottom Hole Pressure; and when the Bottom Hole Pressure of the well is known, splitting the model into a surface submodel, a Vertical Lift Performance submodel, which extends from the Bottom Hole Pressure to a tubing head pressure, and an Inflow Performance Relationship submodel, which extends from a reservoir pressure to a Bottom Hole Pressure, run the submodels after the splitting (506, 508) to obtain submodel results in the form of estimated well parameters; determine (212, 512), in a determination process, that the submodel results obtained by running at least one of the submodels match or do not match by comparing the submodel results with the results obtained by at least one of the other submodels, or with liquid production rates; if the results match: save the model and terminate the determination process; and if the results do not match: identify (212, 514) which of the submodels yield results that do not match the results of the other submodels, or do not match the liquid production rates, and terminate the determination process; and calibrate the submodels that yield results that do not match the results of the other submodels, or the submodels that do not match the liquid production rates,