As the oil production of mature reservoirs declines and budget constraints continue to limit rig-based well interventions and infill drilling, the need for practical and cost effective methods of identifying and recovering remaining resources become increasingly essential. The Reservoir Surveillance Mapping (RSM) method, also referred to as ‘the poor engineer's simulator’, provides a result-oriented means of identifying and accelerating oilrecovery. This paper describes practical aspects of RSM efforts in a Niger Delta asset, that involved an integrated reservoir-wide management process with the objective of not only understanding subsurface dynamics during production but also delivering a future work programme for the asset's reservoir blocks.