Seismic velocity estimation method based on spectral inversion
Liu Jie1,2, Zhang Jianzhong1,2,3, Sun Yunbao4, Zhao Tiehu3,4
1. Key Laboratory of Submarine Geosciences and Prospecting Techniques, Qingdao, Shandong 266100, China;
2. Ministry of Education, College of Marine Geosciences, Ocean University of China, Qingdao, Shandong 266100, China;
3. Laboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology, Qingdao, Shandong 266061, China;
4. Qingdao Institute of Marine Geology, China Geology Survey, Qingdao, Shandong 266071, China
Abstract：A method for estimating stratum velocity is proposed by combining spectral inversion and wave impedance recursive inversion. The method consists of two steps:first, a reflection coefficient section is obtained with the spectral inversion of seismic section; then, this reflection coefficient section is transformed to velocity section by wave impedance recursive inversion. The method can not only accurately calculate the reflection coefficient, but also further obtain seismic velocity which closely relates to stratigraphic lithology. Experiments on Marmousi model show that the proposed method is valid. For applications to real data, the piecewise Gardner's equations of density-velocity relations are established based on acoustic and density logging data of Well SH2 in the Shenhu area in the northern continental slope of the South China Sea, and then the proposed method is applied to estimate strata velocity sections from a seismic line passing Well SH2. Based on the estimated velocity section, gas-hydrate reservoirs are predicted. The estimated stratum velocity and predicted gas-hydrate distribution are consistent with drilling and logging data at Well SH2.
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