At the early phases of EOR developments, small scale pilots are commonly used to obtain information of the EOR field development mechanisms. The lessons learnt from these early pilots are subsequently used to de-risk and improve the full field developments.In initial phases, well and reservoir surveillance plays an important role to increase the understanding of the effectiveness of the EOR processes in the various reservoirs. Well-planned and executed reservoir surveillance has proven in the past to de-risk and optimise production and ultimate recovery from reservoirs significantly. This paper discusses the important field development decisions in Thermal Injection projects, which have been based on well and reservoir surveillance results. A clear methodology is presented to select surveillance strategies dependent on the field development decisions that need to be taken.