Geochemistry, origin and accumulation of natural gas hydrates in the Qiongdongnan Basin, South China Sea: Implications from site GMGS5-W08

The recent discovery of natural gas hydrates in the Qiongdongnan Basin (QDNB) during the fifth China National Gas Hydrate Drilling Expedition (GMGS5) confirms the great potential of gas hydrate resources within this basin. Based on the comprehensive geochemical investigation of the hydrate-related gas and hydrate-bearing sediments collected from the drilled site GMGS5-W08, this study determines the source and accumulation mechanism of gas hydrates. The hydrate-related gases from the site GMGS5-W08 consist of abundant methane (81.21%-97.69%) and some C2+ hydrocarbon gases (2.31%-18.79%). The stable carbon isotopic compositions of C1-C3 hydrocarbon gas components indicate that the methane has a mixed microbial and thermogenic origin (-59.5 parts per thousand

Automated summary

The recent discovery of natural gas hydrates in the Qiongdongnan Basin during the GMGS5 confirms the great potential of gas hydrate resources. The study on hydrate-related gases and sediments collected from GMGS5-W08 determines the source and accumulation mechanism of gas hydrates, indicating that methane has a mixed microbial and thermogenic origin.