Challenges and considerations for the development of natural gas hydrates in South China Sea

The preliminary exploration results show that the South China Sea has a broad prospect of natural gas hydrate resources, which mainly occur in the shallow unconsolidated muddy silt of the deep water slope in this area. Its development process integrates hydrate phase transformation, reservoir skeleton breakdown, gas-liquid-solid multiphase seepage and transport, and faces such problems as low gas production per well, difficulty in sustainable production, possible ecological and environmental risks, low economic benefits, and challenge to large-scale development. To realize the commercial hydrate exploitation in this area as soon as possible, the potential resources, exploitation methods, and pilot production progress of hydrate in the major areas of the world are considered. Then, the related scientific problems and engineering challenges in the South China Sea are analyzed from the aspects of hydrate accumulation mechanism, gas-liquid-solid multiphase flow continuous production, ecological environment risks, and technology & equipment. Despite many challenges, relatively systematic experimental equipment for hydrate's basic physical properties, exploitation simulation and mechanical properties has been established in China after more than two decades of continuous researches, which lays the theoretical, experimental, and equipment foundation for the further relevant researches and leads the international level in some technical fields. The potential paths conducive for the commercial hydrate exploitation are proposed, e.g., "multi-gas source co-production of hydrate and deep gas", "CO2 hydrate replacement development and solidification and storage", and "collaborative integrated development of offshore multi-energy areas", and their technical principles and realization means are analyzed.