Optimising the location of oilfield pads

A method includes assigning one or more constraints to an upper surface, assigning one or more constraints to a lower surface, defining a pad configuration, generating pad locations locatable on the upper surface that conform to the defined pad configuration and the assigned constraints for the upper surface and the lower surface, and outputting specifications at least one of the generated pad locations. The method is of applicable to optimising an oilfield and is of use in the location of pads e.g. drilling rigs and in sensing, drilling, injecting extracting and also in steam assisted gravity drainage.