According to the Chapman multi-scale rock physical model, the seismic response characteristics vary for different fluid-saturated reservoirs. For class I AVO reservoirs and gas-saturation, the seismic response is a hi...According to the Chapman multi-scale rock physical model, the seismic response characteristics vary for different fluid-saturated reservoirs. For class I AVO reservoirs and gas-saturation, the seismic response is a high-frequency bright spot as the amplitude energy shifts. However, it is a low-frequency shadow for the Class III AVO reservoirs saturated with hydrocarbons. In this paper, we verified the high-frequency bright spot results of Chapman for the Class I AVO response using the frequency-dependent analysis of a physical model dataset. The physical model is designed as inter-bedded thin sand and shale based on real field geology parameters. We observed two datasets using fixed offset and 2D geometry with different fluid- saturated conditions. Spectral and time-frequency analyses methods are applied to the seismic datasets to describe the response characteristics for gas-, water-, and oil-saturation. The results of physical model dataset processing and analysis indicate that reflection wave tuning and fluid-related dispersion are the main seismic response characteristic mechanisms. Additionally, the gas saturation model can be distinguished from water and oil saturation for Class I AVO utilizing the frequency-dependent abnormal characteristic. The frequency-dependent characteristic analysis of the physical model dataset verified the different spectral response characteristics corresponding to the different fluid-saturated models. Therefore, by careful analysis of real field seismic data, we can obtain the abnormal spectral characteristics induced by the fluid variation and implement fluid detection using seismic data directly.展开更多
On the basis of Chapman＇s（2003） model,as the seismic wave incidences angles vary from 0° to 45° while propagating in anisotropic media（HTI）,the slow S-wave will sufferred by serious attenuation and disp...On the basis of Chapman＇s（2003） model,as the seismic wave incidences angles vary from 0° to 45° while propagating in anisotropic media（HTI）,the slow S-wave will sufferred by serious attenuation and dispersion and is sensitive to fluid viscosity but the P-and fast S-waves don＇t.For slow S waves propagating normal to fractures,the amplitudes are strongly affected by pore fluid.So,the slow S-wave can be used to detect fractured reservoir fluid information when the P-wave response is insensitive to the fluid.In this paper,3D3C seismic data from the Ken 71 area of Shengli Oilfield are processed and analyzed.The travel time and amplitude anomalies of slow S-waves are detected and correlated with well log data.The S-wave splitting in a water-bearing zone is higher than in an oil-bearing zone.Thus,the slow S-wave amplitude change is more significant in water-bearing zones than in oil-bearing zones.展开更多
基金supported by the National Science and Technology Major Project (No. 2011ZX05019-008)the National Natural Science Foundation of China (No. 41074080)+1 种基金the Science Foundation of China University of Petroleum, Beijing (No. KYJJ2012-05-11)supported by the CNPC international collaboration program through the Edinburgh Anisotropy Project (EAP) of the British Geological Survey (BGS) and the CNPC Key Geophysical Laboratory at the China University of Petroleum and CNPC geophysical prospecting projects for new method and technique research
文摘According to the Chapman multi-scale rock physical model, the seismic response characteristics vary for different fluid-saturated reservoirs. For class I AVO reservoirs and gas-saturation, the seismic response is a high-frequency bright spot as the amplitude energy shifts. However, it is a low-frequency shadow for the Class III AVO reservoirs saturated with hydrocarbons. In this paper, we verified the high-frequency bright spot results of Chapman for the Class I AVO response using the frequency-dependent analysis of a physical model dataset. The physical model is designed as inter-bedded thin sand and shale based on real field geology parameters. We observed two datasets using fixed offset and 2D geometry with different fluid- saturated conditions. Spectral and time-frequency analyses methods are applied to the seismic datasets to describe the response characteristics for gas-, water-, and oil-saturation. The results of physical model dataset processing and analysis indicate that reflection wave tuning and fluid-related dispersion are the main seismic response characteristic mechanisms. Additionally, the gas saturation model can be distinguished from water and oil saturation for Class I AVO utilizing the frequency-dependent abnormal characteristic. The frequency-dependent characteristic analysis of the physical model dataset verified the different spectral response characteristics corresponding to the different fluid-saturated models. Therefore, by careful analysis of real field seismic data, we can obtain the abnormal spectral characteristics induced by the fluid variation and implement fluid detection using seismic data directly.
基金supported by the National 863 Program (Grant No. 2007AA060505)
文摘On the basis of Chapman＇s（2003） model,as the seismic wave incidences angles vary from 0° to 45° while propagating in anisotropic media（HTI）,the slow S-wave will sufferred by serious attenuation and dispersion and is sensitive to fluid viscosity but the P-and fast S-waves don＇t.For slow S waves propagating normal to fractures,the amplitudes are strongly affected by pore fluid.So,the slow S-wave can be used to detect fractured reservoir fluid information when the P-wave response is insensitive to the fluid.In this paper,3D3C seismic data from the Ken 71 area of Shengli Oilfield are processed and analyzed.The travel time and amplitude anomalies of slow S-waves are detected and correlated with well log data.The S-wave splitting in a water-bearing zone is higher than in an oil-bearing zone.Thus,the slow S-wave amplitude change is more significant in water-bearing zones than in oil-bearing zones.
