The economics of deepwater oil field developments rely heavily on the availability of high oil production rate wells that can generate early income to pay for the high CAPEX invested in such field developments. In addition to the cash flow is the uncertainty that surround such high CAPEX developments. For example the influence of governments and policy changes leaves the investor no choice than to ensure early recovery of investment. To support the required high oil production rates, the reservoir pressures must be maintained to minimize the chances of breakout of gas in the reservoir in an under saturated system or production of gas cap gas in a saturated system. Often times, the question is not whether to apply a reservoir maintenance scheme or doubts about the strength of the aquifer but when is the appropriate time to implement the water injection scheme and thus optimize the development for stakeholders both in terms of economics and ultimate recovery. The choice of scheme to employ follows the decision to provide reservoir pressure support as part of reservoir management strategy. Water injection in the deepwater setting appear to be a preferable choice over gas given the ready availability of sea water and less complications in the operation of the injection system when compared to gas injection. Further to the decision on the use of water injection for reservoir maintenance is the question of sizing of the injection facility to deliver the required amount of water for the field development. Subsurface and Project engineering teams most often depend on global industry knowledge especially the golf of Mexico to design the injection facilities. However occasions arise where the development plans and aspirations defer. For example, the sizing of the injection system may not have considered the complexity of the reservoirs nor the future development plans for nearby fields. Such occasions may result in ad hoc operational philosophy to optimize oil production. This paper aims to put the shortcomings of water injection limitations in deepwater Nigeria in perspective, identify best practices in such instances and make recommendations for future development planning.