陡倾界面的VSP反射点轨迹规律的分析

本文导出了VSP的二维和三维垂直时距曲线及极小点坐标的表达式,并根据已知参数提出对VSP空间反射点轨迹分布的分析方法。在较系统研究反射点随界面深度、界面倾角、井源距、观测深度、震源方位变化的分布规律的基础上,揭示了VSP与地面共炮点道集反射点的分布关系。这项成果应用于VSP陡倾界面的观测系统设计,可设计出合适的参数;应用于VSP实际资料的解释,可确定出反射点成像的准确位置,并能正确地与地面地震偏移剖面进行对比。

Analysis of VSP reflection-point trajectory on steep dip interface,

We derive the expressions of both the time-distance curves of reflection waves in 2-D or 3-D VSP data and the coordinates of the minimal points. We also put forward the methods for analysing the distributions of VSP reflection points with the use of known parameters. Having systematically analysed how VSP reflection point distribution depends on interface depth, interface dip, offset, observation depth and source direction, we reveal the relationship between VSP reflectionpoint distribution and the distribution of surface seismic common-shot reflection points. When applied in VSP observation system design in the case of dipping interface, this analysis result favours determining proper parameters. The application of this analysis result to real VSP data interpretation will help people to correctly locate VSP reflectionpoint image and to correctly correlate it with surface-seismic migration section.