Achieving Optimal Injection Conformance with Autonomous Outflow Control Devices in Fractured Reservoirs: Case Studies in the South Oman Fields

Abstract Properties including propagating/dilating fractures. Development and growth of thief zones are confirmed by regular run of Multi-Injection Logging Tool (MILT) into the wells plus observing the performance of nearby producers. Although several techniques have been applied to improve the conformance of injection wells, they often lack the ability to effectively address this heterogeneity and achieve optimal injection. This paper presents field case studies in the South of Oman demonstrating the successful application of Autonomous Outflow Control Devices (AOCDs) in injection wells. AOCDs are innovative downhole tools strategically placed within the wellbore. These devices act as autonomous valves, automatically choking back fluid flow in thief zones when a predefined upper flow rate limit is reached. This dynamic flow control mechanism redirects injected fluids to less-productive zones, promoting a more even distribution and maximizing reservoir contact. The first installations of AOCDs in Oman have yielded promising results, significantly improving injection conformance and well performance. Here's a detailed look at the key findings: 1) Enhanced Injectivity Profile: Compared to conventional completions, the wells equipped with AOCDs exhibit a significantly different injection pressure-rate (Q vs P) profile. This profile indicates a more favourable injectivity response, characterized by a reduced pressure increase for a given injection rate. This signifies a more even distribution of injected fluids across the entire reservoir as opposed to the rapid pressure rise observed in conventional completions due to concentrated flowing thief zones. 2) Reduced Thief Zone Dominance: MILT data from the AOCD wells after installation reveals a dramatic reduction, exceeding 75% in some instances, in the contribution of thief zones from the total injected volume. This substantial decrease effectively mitigates the further growth of these preferential flow paths and their detrimental impact on reservoir sweep efficiency. 3) Increased Production Efficiency: The optimized injection profile achieved by AOCDs is believed to have significantly contributed to a 30% increase in oil production from nearby producing wells. Additionally, a lower water cut was observed, indicating improved recovery of valuable hydrocarbons. The field data presented in this paper provides compelling evidence for the effectiveness of AOCDs in achieving optimal injection conformance and well performance in fractured reservoirs. This innovative technology not only enhances well efficiency and reduces operational costs but also offers valuable insights for future well-completion strategies. By enabling more effective reservoir management, AOCDs pave the way for improved field development practices and ultimately contribute to maximizing oil recovery from fractured reservoirs.