Status of Natural Gas Hydrate Flow Assurance Research in China: A Review

Natural gas hydrates (NGH) are prone to causing pipeline blockage in flow assurance, attracting considerable attention in the petroleum industry. This work reviews the significant progress in hydrate flow assurance research in China. Gas hydrate structures are briefly introduced to provide a basic understanding, while the application and development of hydrate management strategies in China are summarized. Subsequently, the development and improvement of hydrate phase equilibrium models are presented, which have been widely applied to the practical challenges of flow assurance. Moreover, kinetics research involving hydrate nucleation, growth, and decomposition are summarized, including nucleation mechanisms, induction time, memory effect, hydrate growth at different interfaces, hydrate growth at a microscopic level, and hydrate decomposition under different systems. The current research status of hydrate slurry flow is also analyzed in detail, covering the viscosity and flow resistance of hydrate slurry and the mechanisms of hydrate particle aggregation, deposition, and blockage. In addition, even though the numerical models of hydrate slurry multiphase flow have been sorted out, the accurate quantitative calculations and risk assessments are still in the initial stage, presenting significant room for improvement. Although substantial research progress has been made in China regarding gas hydrate flow assurance, considerable effort should be devoted to further understanding the intrinsic mechanism work to improve the applicability of various models. This review discusses the current developments, existing problems, and future prospects in the various basic hydrate flow assurance fields in China. It aims to provide readers with an overview of hydrate flow assurance research in China, hoping to provide a reference for developing this field.