Gas hydrate and associated free gas occurrence in the Dongsha Area of northern South China Sea
Presenter：Hsueh-Fen Wang Adviser： Shu-Kun Hsu
To understand links among seafloor methane seepage, subsurface gas hydrate, origin of gas source and structural styles controlling the formation and accumulation of gas hydrate, high resolution multi-channel seismic data were interpreted in this region. Additionally, seismic attributes, interval velocity model, and acoustic P wave impedance were obtained to better delineate the spatial distribution of gas hydrate. Hydrate-bearing sediments are characterized by weak reflection (i.e. blanking zone) above BSRs, high velocities and relatively small acoustic impedance differences, while enhanced reflection, low frequency, and low velocities beneath BSRs suggest the presence of underlying free gas beneath solid hydrate. Both faults and mud diapirs are useful conduits, allowing methane gas to migrate upward and linking free gas zones beneath BSRs, hydrate zones and seafloor methane seepage.
References
Lun Li, Xinhua Lei , Xin Zhang , Zhibin Sha.(2013). Gas hydrate and associated free gas in the Dongsha Area of northern South China Sea. Marine and Petroleum Geology, 39 (1), 92-101
Wu S., Zhang, G., Huang Y ., Liang, J., & Wong, H. K. (2005).
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Gas hydrate occurrence on the continental slope of the northern South China Sea. Marine and Petroleum Geology, 22, 403-412.