The application of post-stack impedance inversion without well to the prediction of gas hydrate distribution in T study area
WAN Xiao-Ming1,2, LIANG Jing1,2, LIANG Jin-Qiang1,2, LIN Lin1,2, SHA Zhi-Bin1,2, CHAI Yi1,2, CAI Zhen-Hua3
1. Key Laboratory of Marine Mineral Resources of Ministry of Land and Resources, Guangzhou 510760, China;
2. Guangzhou Marine Geological Survey, Guangzhou 510760, China;
3. Drilling Division, CNPC Offshore Engineering Co., Ltd, Tianjin 300280, China
Aimed at investigating the geological conditions and the modes of occurrence of gas hydrate on the northern slope of South China Sea, the authors established a three-dimensional interval velocity model based on the three-dimensional seismic data and stacking velocity spectrum under the condition of lack of logging data, and then transformed the data to low impedance background model. Subsequently, the authors extracted pseudo wells and tied them accurately, and finally obtained an absolute impedance and fine velocity bodies by the constrained sparse spike inversion method. Meanwhile, the authors comprehensively utilized seismic and inversion data,analyzed the best threshold value for distinguishing the gas hydrate in the study area and, on such a basis, quantitatively interpreted the gas hydrate. The results obtained show that:First,the velocity of gas hydrate is about 2050~2150 m/s, and P-impedance is above 3.9×106 kg·m-3·m·s-1 in the study area,which are higher than the velocity and impedance of surrounding rock;Second,the distribution of gas hydrate is extensive, especially in the middle west and southeast region,where the preliminary estimated maximum thickness is up to 48m.
万晓明, 梁劲, 梁金强, 林霖, 沙志彬, 柴祎, 蔡振华. 叠后波阻抗无井反演技术在T研究区天然气水合物分布预测中的应用[J]. 物探与化探, 2016, 40(3): 438-444.
WAN Xiao-Ming, LIANG Jing, LIANG Jin-Qiang, LIN Lin, SHA Zhi-Bin, CHAI Yi, CAI Zhen-Hua. The application of post-stack impedance inversion without well to the prediction of gas hydrate distribution in T study area. Geophysical and Geochemical Exploration, 2016, 40(3): 438-444.
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