Application of Autonomous Inflow Control Valve Technology for Ultralight Oil in a Mature Field in Malaysia

Abstract

Abstract Kinabalu field is a mature field which has been in production since 1998 and faces significant challenges with excessive gas and water production issues. The presence of a large gas cap and moderate aquifer strength in this reservoir results in early water and gas breakthroughs which reduced the oil production and recovery due to poor influx distribution along the wellbore. Due to the unique feature of the Autonomous Inflow Control Valve (AICV) which operates autonomously in ultra-light oil, two Kinabalu wells were completed with AICV joints and annular isolation packers for compartmentalization of production intervals. AICV technology is based on the difference in the pressure drop in a laminar flow element (LFE) compared to a turbulent flow element (TFE) and has the capability to shut-off the main flow autonomously when an unwanted fluid such as water or gas breakthrough occurs. This paper presents the key design aspects for designing the AICV application including reservoir characterization, flow modeling, and selection of appropriate valve configurations. Besides, the comparison between pre and post AICV application will also be discussed and explained. In the first part, the calibrated subsurface simulation was used to model the fluid flow to determine the most optimum AICV installation. It involves the understanding of how to distribute the AICVs and isolation packers within the horizontal well section. It is crucial to ensure the balance between pressure drawdown and maximum fluid flow for each compartment designed. Next, the design was re-optimized once the post drilling logs were available. The actual permeability and saturation logs were analyzed and used as the key input. In this case study, the packers were placed in the low permeability zones to maximize the effect of zonal isolation. Besides, additional packers were also being installed at the heel of the high permeability zone to control the unwanted gas breakthrough. The post-installation performance evaluation showed that AICV managed to choke back gas. The updated post drilling subsurface model was discussed to predict the performance of AICV installed. The paper shed some light on the actual field experience and interesting lessons learned to be considered for AICV application for very thin prolific oil sand.