Limiting Water Production Using Linear Darcy’s Flow Concept in an Open Hole Gravel Pack Completion in Deepwater West Africa

摘要

Well A from a deepwater development project in West Africa was designed to produce oil from a sandstone reservoir buried approximately 2200m below seabed.To maximize reservoir exposure,the trajectory was designed to have a sub horizontal drain(70°)over a 430m long open hole.Sand control was also required so that sand free production will be ensured.The Open hole gravel pack technique was selected to achieve these objectives. While drilling the reservoir section,a 43m long unexpected water bearing layer was found below the production casing shoe,100m away from the main oil reservoir objective.With no specific equipment available to provide a perfect isolation of the unexpected water bearing sands encountered,alternative plans had to be considered for completion of the well on a short timeframe.Being an open hole completion,it was considered too risky to suspend the well in order to procure specialized equipment for water shut-off.The Drilling and Completion team made the decision to apply the physics of linear Darcy’s flow to mitigate the potential water production. This paper aims at describing how the challenges brought by this water zone were successfully overcome leading to the delivery of a$90M well showing positive initial results i.e.good PI,good skin, no sand production and no noticeable water production.