The paper presents an optimisation method for the systematic evaluation of the economic production capacity of an offshore oil production platform. The problem is formulated as sequential mixed-integer liner programs to keep the mathematical comlexity at a low level. Continuous variables represent individual well, jacket and topsides costs and discrete variables are used to select or deselect individual wells within a defined field grid. The mathematical formation is concise and efficient to enable future extensions to consider uncertainty in reservoir performance and actual development costs. The new method is illustrated with two hypothetical fields that are based on real-life examples in the North Sea.