Several operational problems or failures may occur in producers and injectors wells on oil fields and reduce the production. Often the solution to this problem is the well intervention with a drillship. If the production platform itself has an intervention rig, this operation becomes more agile and less costly. Despite providing greater flexibility through the active management of production, the existence of an intervention rig attached to the platform usually increases the required investment compared to alternative without a dedicated rig. The objective of this dissertation was to propose a methodology, based on real options theory, to quantify this flexibility. The methodology was applied to a hypothetical case study in the pre-salt area in which was analyzed the options for intervention in producing wells. The proposed methodology was able to quantify the improvement provided by a dedicated rig. The probability of failure, the waiting time for the drillship, the failure type and duration of the intervention were factors that impacted the value of flexibility.