Summary This paper presents an integrated workflow to optimize water injection strategy in a large carbonate reservoir offshore Abu Dhabi, characterized by vertical heterogeneity and lateral variation. The field currently operates over 100 water injectors (around 140 historically, including inactive wells) and five gas injectors. The reservoir is subdivided into 16 geological layers and six radial engineering sectors. Injectors are categorized into three functional types based on position relative to reservoir contacts: down-dip water injector (DDWI), roll-up water injector (RUWI), and inner-ring water injector (IRWI). The study integrates three main approaches. First, deterministic simulation is used to highlight the physical impact of each injector group. Second, statistical analysis employs a 55- case Latin Hypercube design across 16 independent injection rate limits to capture nonlinear interactions and rank correlations between the rate limits and simulation results of reservoir pressure, oil production, GOR, and water cut. Third, engineering judgment incorporates production trends and bottomhole pressure history to interpret results in the context of field operations and surface constraints. Key findings from all three approaches are aligned. RUWIs contribute most to pressure support but require careful control to avoid early water breakthrough. IRWIs clearly reduce GOR and stabilize volume allocation among water injectors, although their pressure support effect remains limited at this early stage of deployment. DDWIs show limited added value under current total water injection constraints. Two representative field examples illustrate these dynamics. A southern sector highlights the limited effectiveness of DDWI. A northwest sector shows early GOR improvement with a RUWI-IRWI combination around a high-GOR producer. These cases help validate the broader recommendations. The outcome is a flexible strategy for injection allocation: shift of water away from less effective DDWI, use of RUWI for effective reservoir pressure support, and deployment of IRWI where GOR control is needed. The framework supports ongoing surveillance and adjustment, aiming to balance pressure, avoid early breakthrough, and adapt when new field data becomes available.
Inokuma et al. (Mon,) studied this question.