A Review of the Resource and Test Production of Natural Gas Hydrates in China

China has been attaching great importance to research on natural gas hydrate resources. Since the mid-1990s, China has experienced three stages of resource prediction, investigation, and test production. Until now, five hydrate accumulations have been discovered by drilling and sampling in the Shenhu, Dongsha, Qiongdongnan Basins, and offshore Taiwan of the South China Sea and in the Muli area of Qilian Mountain, and seven hydrates have been inferred by various indicators, including geology, geophysics and geochemistry in the South China Sea, the East China Sea, and the Qinghai–Tibet Plateau. According to the hydrate stability zone, the natural gas hydrate resources in the South China Sea are estimated to be 64.6 × 1012 m3, those in the East China Sea are ∼28.5 × 1012 m3, and those in the terrestrial permafrost are ∼38 × 1012 m3. The total amount of the natural gas hydrates in China reaches up to 131.1 × 1012 m3, which is twice the amount of China's conventional natural gas resources. China has successfully conducted the five field test production of gas hydrates in the Muli permafrost region of Qilian Mountain and in Shenhu area of the South China Sea since 2011, in particular first using horizontal well technologies to exploit hydrates that occurred in the fine-grained reservoirs. It is expected that commercial production from the hydrate reservoir will come true in the 2030s.