In Sakhalin Energy the oil and gas production from all the wells is monitored in real-time by data-driven models. These models are based on single-rate well test data, test-by-difference data and/or 'synthetic' data generated by physical models. The system is technically easy to maintain, fast to simulate and reconcile with the fiscal meters. SEIC has two new facilities with good instrumentation that allowed for a successful deployment of FieldWare Production Universe for real-time production surveillance and allocation. This paper also highlights the key lessons learnt from the roll-out exercise and the key issues and risks involved during the implementation and execution process.