A method is disclosed for controlling production of oil and/or gas from an underground reservoir by means of a closed loop production control system, in which: an assembly of monitoring sensors (4) monitor the physical properties of hydrocarbon and other fluids within the reservoir; a plurality of high order and/or low order mathematical reservoir models (5,7) calculate each an estimate of the physical properties of hydrocarbon and other fluids in the hydrocarbon containing formation and in the wells; the mathematical reservoir models (5,7) are iteratively updated in response to data provided by the assembly of sensors such that any difference between the properties monitored by the assembly of sensors and those calculated by each of the reservoir models is minimized; an optimal mathematical reservoir model (5,7) or an optimal combination thereof is selected during at least one updating step for which an averaged difference between the calculated properties and the properties monitored by the assembly of sensors (4) is minimal; and an optimization algorithm (8) controls, on the basis of data provided by the selected optimal mathematical reservoir model or optimal combination thereof, production control assemblies of a plurality of wells which traverse the formation.