OS3B-8:EROSIONAL-SEDIMENTARY CONTROLS ON THE ACCUMULATION AND DISTRIBUTION OF GAS HYDRATE IN THE SHENHU AREA, NORTHERN CONTINENTAL SLOPE OF THE SOUTH CHINA SEA

Ming SU^1,, Rui YANG¹, Zhibin SHA ², Jinqiang LIANG ², Zenggui KUANG², Nengyou WU^1,, Shaohua QIAO^{1, 3}, Pibo SU², Xiaorong CONG¹

1. Guangzhou Centre for Gas Hydrate Research, Guangzhou Institute of Energy Conversion, CAS, CHINA; 2. Guangzhou Marine Geological Survey, CHINA; 3. University of Chinese Academy of Sciences, CHINA

In 2007, the drilling results of the GMGS-1 in the northern continental slope of the South China Sea revealed the heterogeneous distribution of gas hydrate in the Shenhu Area. Based on the integrated analysis of logging and seismic data, the tectono-sedimentary framework had been built up, and three erosional-sedimentary events in Pleistocene had been identified. Related to the scouring of Boundary T1 (at about 1.8 Ma), the sediments eroded by the small-scale deep-water channels in the north could be re-transported downward and re-deposited proximally as lobes. Because of the abundant sediment supply from the progradation slope, slides were widely developed. Besides, seventeen submarine canyons associated with the sediments failures could be described through the seafloor topography, also some slumps triggered by the steep relief could be observed. Although the lithology and grain size of the Pleistocene sediments were similar in the core samples, the re-deposited lobes might be supposed to have good property and promised the potential reservoir for gas hydrate. On contrary, the slides with continuous reflectors would be regarded as the compact layer to hinder the fluid/gas migrating upwards with low flux. And the slope confined canyons could erode the previous strata, and transport the sediments to the lower slope further, which might destroy the ribbon lobes to isolated or patchy deposits. All these three erosional-sedimentary events influenced the distribution of potential reservoirs for gas hydrate, which might be considered as the crucial factors controlling the accumulation and distribution of gas hydrate in the Shenhu Area.