TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractA business case to determine the economic value of deploying subsea intelligent well completions in a subsea development project deepwater West Africa has been developed. Deployment of smart well technology in the base case development of the case field provides an opportunity to develop 20% incremental reserves that would otherwise be uneconomical to develop without the ability to use a multizone completion solution. This results in a 50% gain (risked gain) in NPV for the project. The method is based on an analysis of possible completion failure scenarios, the probability of occurrence of these scenarios and the reliability of the downhole intelligent completion equipment. The cost analysis carried out, weighed the benefit of smart wells against conventional and stacking (commingling of zones) completion types. CAPEX was risked using Decision Tree analysis with data input from a wide range of data bases including fields in the Nigerian DeepWater blocks.