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地下球界面在各种地震剖面上具有不同的表现形态。上半球形和下半球形界面在法向深度剖面上都表现为一条形状相同的双曲线,但是前者双曲线的顶点位于后者的上方。于是可用一种新的三维偏移方法,即先沿测线方向偏移,再以测线为轴进行一次转动,完成侧面波的空间归位。球界面在法向时间剖面上,其法向双程旅行时间t_0和y的关系曲线不是双曲线。对于固定的测线说来,若x是常数,当y=0时,t_0取最小值;当y→±∞时,t_0取最大值。球界面在叠加深度剖面上,其视深度与y的关系是一条四次曲线。在叠加深度剖面上进行偏移归位,不需偏移速度和时深转换速度。利用此种剖面可以直接确定球界面的空间形态。
The underground ball interface has various manifestations on various seismic sections. Both the upper hemisphere and the lower hemispherical interface appear as a hyperbolic curve of the same shape in the normal depth profile, but the hyperbolic vertex of the former lies above the latter. So a new method of three-dimensional migration can be used, that is, along the line direction of the first offset, and then measured line as the axis for a rotation, the completion of the spatial side of the return wave. In the normal time profile of the ball interface, the relationship between the normal two-way travel time t_0 and y is not hyperbolic. For a fixed measurement line, if x is a constant, t_0 takes the minimum value when y = 0, and t_0 takes the maximum value when y → ± ∞. Ball interface in the superimposed depth profile, the depth of its relationship with y is a quadratic curve. Offset homing on overlay depth profiles without offset speed and time-to-depth conversion speed. The use of such profiles can directly determine the spatial shape of the ball interface.