A computer system for modelling and controlling a hydrocarbon reservoir through management of fluid flow at individual wells. The computer system has program instructions which operate a computer model which uses oilfield production data to provide a model of future production. The model comprises an optimal regression model which represents injector and producer wells whose fluid flow characteristics are highly correlated with the fluid flow characteristics of the well of interest; the application of parsimonious information criterion techniques to identify well pairs that statistically contribute information to the optimal regression model; and a statistical reservoir model comprising the product of the optimal regression model and a significance matrix. The system is also provided with control means, responsive to the output of the computer model in order to control wells in the hydrocarbon reservoir.