A Flat‐Lying Transitional Free Gas to Gas Hydrate System in a Sand Layer in the Qiongdongnan Basin of the South China Sea

作者：Zenggui Kuang, Ann E. Cook, Jinfeng Ren, Wei Deng, Yuncheng Cao, Huimin Cai · 发表于：Geophysical Research Letters · 年份：2023 · DOI：10.1029/2023gl105744 · 被引用次数：23 · 研究领域：Methane Hydrates and Related Phenomena、Hydrocarbon exploration and reservoir analysis、Geology and Paleoclimatology Research

Abstract Most marine gas hydrate systems follow a vertical pattern with hydrate overlying free gas. Here we document the discovery of a gas to hydrate system in a horizontal sand layer in the Qiongdongnan Basin of the South China Sea. Eight wells were drilled by the Guangzhou Marine Geological Survey in 2021–2022 to investigate the occurrence and mechanisms responsible for the formation of the system. We describe a free gas‐bearing sand reservoir at the center of the system sustained by advecting hot fluids and gas; away from the advecting zone, the cooler, surrounding sand reservoir is filled with hydrate. Observations at this site show that advective heat has a large control on hydrate formation in sands and may be a key mechanism which allows gas migration within the hydrate stability zone and the formation of high‐saturation hydrate in sand layers.