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在加拿大安大略省的Sudbury盆地进行了多井源距三分量垂直地震剖面(VSP)实验作为LITHOPROBE Sudbury Transect的一部分。主要目的是确定Sudbury盆地中部的浅层速度构造、开发有效的VSP数据处理流程、对比VSP测量成果与地面地震反射数据以及证明在结晶岩环境下VSP方法的有效性。VSP数据的处理步骤包括水平分量数据的旋转、速度分析的旅行时反演、波场分离的拉冬变换以及横波数据的初步分析。波场分离以后,拉平后的P波和S波上行波场呈现出来自三个深度一致的反射同相轴。VSP-CDP转换剖面和走廊叠加剖面与高分辨率地面反射数据具有很好的相关性。除了对Chelmsford地区合成地震模拟获得P波和S波的实际速度模型外,VSP实验利用三分量矢端曲线分析法给出了反射界面倾向的独立估计值,它表明在Chelmsford井孔中的深度大约为380m处,Chelmsford和Onwatin地层之间接触面的倾向大约为南东10.5°。这项研究证明,多井源距三分量VSP实验能够为结晶岩区中的浅层地壳地震研究提供重要的约束和辅助信息。因此,VSP技术在地面地震反射技术和测井测量之间架起了一座桥梁。
A multi-well source three-component vertical seismic profiling (VSP) experiment was conducted as part of the LITHOPROBE Sudbury Transect in the Sudbury Basin, Ontario, Canada. The main objective is to determine shallow velocity tectonics in the central Sudbury Basin, to develop effective VSP data processing flows, to compare VSP measurements with surface seismic reflection data, and to demonstrate the effectiveness of the VSP method in a crystalline rock environment. VSP data processing steps include the rotation of horizontal component data, the travel time inversion of velocity analysis, the winter transformation of wavefield separation and the preliminary analysis of shear wave data. After wavefield separation, the flattened P-wave and S-wave uplink wavefields emerge from three depth-consistent reflection events. VSP-CDP transition profiles and corridor superimposed profiles have good correlation with high-resolution ground-reflection data. In addition to the actual velocity model for P-wave and S-wave for the synthetic seismic simulations in the Chelmsford region, the VSP experiment uses a three-component vector end curve analysis to give an independent estimate of the reflection interface propensities, which indicates a depth approximately in the Chelmsford wellbore At 380 m, the tendency of the interface between the Chelmsford and Onwatin formations to be about 10.5 ° N. This study shows that multi-well source distance three-component VSP experiments can provide important constraints and auxiliary information for shallow crustal seismic studies in crystalline rock areas. As a result, the VSP technology bridges the gap between ground seismic reflection and logging measurements.