Flow Control Valves and Inflow Control Devices Optimized for Wellbore Cleanup and Production (2014)

Abstract Static inflow control devices (ICDs) have been designed to provide a more even inflow across production zones by adjusting the completion pressure differential to balance reservoir drawdown. Unwanted fluids are delayed, oil production is enhanced. Recently, companies have offered "intelligent" completion products that include fully addressable downhole electric control of annular flow control valves (AFCVs) whose inflow cross-sectional area can be dynamically changed in response to variations in production (e.g. to control water ingress or increase oil production). This paper examines the use of surface-controlled AFCVs to improve wellbore cleanup, and both AFCVs and ICDs to improve production. Open areas of the AFCVs, positioned at the edge of reservoir compartments, are employed as optimization variables in a simulation study of wellbore and near wellbore cleanup. Similarly, AFCV areas and ICD settings are adjusted to optimize the subsequent production cycle. The study focuses on a lower cretaceous carbonate rock reservoir with tight facies where a single horizontal wellbore traverses three distinct compartments. Long multi-lateral wells are typically employed in this region and wellbore cleanup, and thereby productivity, can be a key component in the success of the well. Introduction Following a review of recent literature on this topic, the AFCV used in this simulation study is discussed. A brief overview of the reservoir simulator and well model is then given. A new, sophisticated wellbore cleanup simulator that was used for optimization of this process, is described. Details of the case study, loosely based on a middle-eastern carbonate reservoir with tight facies and a gas cap, bottom water, and three distinct compartments through which a long horizontal wellbore has been drilled, are presented. The body of this work first examines various methods to optimize the cleanup phase and discusses the best way to achieve uniform productivity along the entire length of the well. Next, during the subsequent production cycle, AFCV area settings are periodically optimized, the frequency and nature of these updates being specified by the operator. Finally, a comparison is made with ICD settings which are fixed at the beginning at the production cycle and optimized to achieve either (i) a best Net Present Value (NPV) or (ii) an improved conformance in compartments with less productivity. Following a discussion of results from these studies, conclusions are presented including recommendations to improve both wellbore cleanup and production. Review A brief review of recent literature concerning optimization of ICDs and ICVs is as follows. Fu et. al. (2014) discuss a simulation study wherein static ICDs were optimized to achieve long term well productivity. They propose the target objective for optimization given well BHP, daily production and no-water production period constraints. A comparison was given between production cycles utilizing open-hole, constant ICD and optimized variable ICD completions. Akbari (2014) analyses correlations for various ICD designs in order to optimize ICDs along a horizontal wellbore. A number of key parameter indicators, including number of ICDs and length of intervals to equalize the inflow, are included. Rodriguez et. al. (2014) talk about the impact of intelligent completions, including a sliding sleeve and concentric dual completions, on potential productivity in the Shushufindi-Aguarico oil field, Ecuador.