Study on the Evolution of Pore Characteristics of Cement Slurry in Offshore Gas Storage Wellbore Based on Temperature-Coupled Hydration Kinetics and Deep Learning

Offshore gas storage facilities are key to resolving the mismatch between associated gas production from offshore oilfields and platform energy demand, and reducing resource waste; current research mainly focuses on converting depleted oil-gas reservoirs, with priorities on the adaptability of associated gas treatment to storage design, drilling/completion optimization, and wellbore integrity assurance, which is critical for long-term safe operation and relies on cement sheath quality control and cement performance regulation under temperature-pressure coupling, though targeted technical frameworks exist, key bottlenecks still remain. In deepwater, the significant temperature difference (“low at mudline, high at wellbore bottom”) causes strong spatiotemporal variations in cement hydration and microstructure evolution at different wellbore depths, with dynamic porosity easily forming gas channeling paths, so to address this, this study first established a cement slurry hydration kinetics model for different curing temperatures, and based on classic hydration kinetics, it quantified temperature’s impact on reaction rate via experiments, enabling accurate prediction of cement hydration under varied temperature fields [13]; meanwhile, using environmental scanning electron microscopy (ESEM), in-situ microporosity tests were conducted to obtain cement slurry micrographs under different curing temperatures, and for precise microstructural analysis, a deep learning-based identification framework was built: image preprocessing eliminated noise, an improved segmentation algorithm achieved automatic division of cement matrix and pores, and porosity was quantified. This study, which covers hydration modeling, ESEM tests, and deep learning analysis, aims to verify how deepwater temperature difference regulates cement hydration/porosity evolution and its correlation with gas channeling risk, provides experimental support for subsequent coupled models, offers an experimentally validated basis for deepwater cement sheath quality control and gas channeling prevention, and holds practical value for optimizing offshore gas storage wellbore integrity systems.