Comprehensive Investigation of Near-Wellbore Damage in Produced Water Reinjection: Bridging Microfluidic Insights and Core Flooding Test Analyses

Abstract The disposal of produced water poses a significant challenge for the oil and gas industry due to its voluminous nature and the presence of diverse contaminants, rendering treatment and disposal processes costly and intricate. Adhering to stringent environmental regulations, reinjection of produced water into reservoirs emerges as an optimal solution, not only facilitating hazardous water disposal but also aligning with pressure maintenance and oil production enhancement strategies, such as water flooding. In the Danish North Sea offshore well scenario, as delineated in the 2022 report by the Danish Energy Agency, a substantial volume of produced water is generated alongside limited oil production. The magnitude is illustrated by the production of approximately 3.7 billion m3 of oil accompanied by 30.8 billion m3 of produced water. Nevertheless, challenges persist with produced water reinjection, particularly concerning near-wellbore damage during the reinjection process. To overcome this challenge, a comprehensive understanding of formation damage mechanisms and identification of primary contributors become imperative. Conventional methods, relying on core flooding experiments involving pressure readings during injection and analytical analysis of produced water, offer insights into potential damage mechanisms. However, microfluidic experiments, offering visual analyses of damage mechanisms and pore plugging materials, provide a more nuanced perspective. This research seamlessly integrates both core flooding and microfluidic experiments utilizing Danish North Sea Field-produced water and seawater. The core flooding results unequivocally identify inorganic sediments, notably Fe3Si, as the primary cause of pore clogging. In contrast, microfluidic experiments shed light on the substantial contribution of bacterial action, specifically biofilm formation, to the intricate pore plugging mechanisms. This multi-faceted approach enhances the precision of understanding and mitigating near-wellbore damage during produced water reinjection processes.