First Implementation of Zonal Integrity Recovery Through a Regenerative Hydraulic Seal

Abstract An effective zonal isolation is the primary objective of well cementing. However, achieving a hydraulic seal capable of withstanding stresses, and loads at the formation-cement-casing interface remains one of the greatest engineering challenges. Few cement designs deliver long-term technical performance. Issues such as structural failure, mechanical degradation of the cement, and continuous exposure to HPHT conditions, H2S, and CO2 lead to volumetric loss in the cement sheath. This results in the formation of microchannels and cracks that compromise both the isolation and overall well integrity, leading to increased operational costs and damage that shortens well life. In response to the above outlined scenario, this paper presents a comprehensive analysis covering simulation, design, laboratory testing and the operational implementation of a regenerative solution in the North Kuwait area- an environment known for sustained casing pressure, high temperatures, and elevated gas concentrations characteristic of the reservoir. The regenerative system was deployed in a Zubair well, where the cement sheath is subjected to repeated operational stresses due to multiple cycles of zone transfer (plug-and-perf operations). Under these conditions, conventional cement systems often experience progressive degradation in sealing capacity, leading to compromised zonal isolation. In contrast, the self-regenerating cement system demonstrated intrinsic self-regenerative properties, enabling direct comparison with conventional high-performance slurries through evaluation of sealing capability, zonal isolation, and mechanical strength. The system's ability to regenerate and reseal micro-annuli or fractures following each pressurization and perforation cycle highlights its robustness in maintaining long-term integrity. Unlike conventional cement designs that provide a static barrier, this system regenerates multiple times, thereby sustaining a durable cement sheath across a wide range of field conditions. This repeated regeneration ensures effective zonal isolation even after successive damage cycles, mitigating risks of fluid migration and enhancing well reliability over extended production lifetimes. Comparative results confirm that the self-regenerating cement system exhibits superior performance, particularly in environments requiring resilience against cyclic mechanical loading and long-term zonal isolation. As a long-term solution, the article highlights the self-regenerative properties of the system, molecules embedded into the cement slurry that create crystal growth in potential high leak pathways in either a water or hydrocarbon environment, and which show sustained stability when evaluated through ultrasonic CBL logging tools. These tools revealed improved sealing performance as indicated by low amplitude (AMP×5 0–20 <2), Bond Index = 1, no interconnection through porous or permeable zones of the cement, strong correlation, high acoustic impedance, and absence of microchannels. Finally, based on an integrated engineering approach involving laboratory testing and simulation, along with an effective Preflush design, the regeneration system demonstrates that when exposed to various stress regimes, mechanical loads, and well environments, it consistently outperforms conventional and advanced cement systems.