Novel workflow to optimise annular flow isolation in advanced wells

Advanced well completion with multiple, downhole flow control devices such as Inflow Control Devices (ICDs), are a proven and effective solution to mitigate water/gas breakthrough and coning problems in horizontal and multilateral wells. An important parameter adversely affectinthe ICD completion's performance is the annular flow. Such annular flow can be minimised or eliminated by segmenting the wellbore into a number of compartments by installing Annular Flow Isolation (AFI). Installation of sufficient AFI at the optimum locations is a key step in achieving the desired well performance. This number of AFI devices is itself constrained by both costs and risks associated with installing the completion string in a long wellbore of complex geometry. Previous AFI design workflows were based on either a single well parameter or a static well-reservoir model that do not consider the total lifetime benefits of the technology. A new AFI design methodology that accounts for the well's lifetime performance has been developed to ensure optimal AFI design in terms of the location and number of AFI installed along the length of the completion. This novel workflow is based on the concept of, to a degree, mimicking the inflow performance of an "ideal" completion (i.e. the completion where AFI is installed between every 12 m completion joint) with a reduced, realistic number of AFIs. The great advantage of this workflow to optimise the AFI design is that it is based on the well's lifetime production performance while at the same time limiting the computation to a single reservoir simulation run for each number of AFIs. The workflow achieves this by ranking the AFI locations based on a criterion related to the annular pressures. A significant recovery increase can be achieved for wells designed with this new workflow when compared to previously proposed AFI design protocols. The learnings from this study can thus be employed by well engineers to optimally design advanced well completions.