The Design of Annular Flow Isolation in Advanced Wells under Reservoir Uncertainty

Abstract

Advanced well completions are proven and effective solutions to mitigate water/gas breakthrough problems in horizontal and multilateral wells. An important parameter adversely affecting the (Autonomous) Inflow Control Devices [(A)ICD] completion’s performance is the annular flow. The flow impacts can be minimised or eliminated by installation of a sufficient number of Annular Flow Isolations (AFIs). This number is in its turn constrained by the completion string costs and risks of its installation in a long wellbore of often-complex geometry. In addition, most industry, AFI design, workflows have been based on the evaluation of a static well-reservoir model or static parameters. (MoradiDowlatabad et al., 2014) developed a novel AFI design methodology to optimise number and location of a limited number of AFIs based on the lifetime well performance. The workflow delivers significant improvement in the total oil production for the wells deployed new AFI design comparing with the wells designed by the traditional workflows. However, the workflow relies on the calculations of numerical reservoir/well models to identify the optimal AFI design, yet the reservoir simulation models are always uncertain to some extent. A robust approach is proposed to include impacts of the reservoir uncertainties into the AFI design decision workflow.