【摘要】 多次波的剩余时差分析法是在CMP道集动校正基础上进行的.根据工区多次波的频率范围,要求多次波的剩余正常时差必须遵循下列3个原则:①在最小炮检距处的多次波剩余时差必须超过1/4甚至1/2的低频周期时间;②最大炮检距与最小炮检距之间多次波剩余时差之差必须大于一个低频周期时间;③最大炮检距与最小炮检距之间多次波的剩余时差之差必须小于(n—4)倍的高频周期时间.其中n为CMP道集的覆盖次数.只要遵守上列3条原则,就可使多次波落入多次波叠加方向特性的压制区内.文中应用了精确的多次波剩余时差式,并用双曲线进行非线性最小二乘法拟合,绘制出一套多次波叠加方向特性曲线.平均拟合误差小于十万分之一.根据这一方法,在一个目的层段存在严重多次波干涉的地区进行地震采集试验,获得了压制多次波的很好效果,并在该区找到了一些新含油圈闭.更多还原

【Abstract】 The method of residual normal moveout analysis for multiple is based no NMO correction of CMP gather. According to the frequency range of multiple in the area, we set the residual NMO time of multiple to follow the three principles as follows : ①at the nearest offset the time of multiple residual NMO shall be exceed one forth or even one second period of lower frequency ;②the time difference between residual NMO at maximum offset and residual NMO at minimum offset for the CMP gather shall be more than one period of lower frequency ; ③the time difference between residual NMO at maximum offset and residual NMO at minimum offset for the CMP gather shall be less than ( N -4) times period of high frequency, the N is folds of CMP gather. If we follow above principles then we could force the multiples to be fallen into the reduction zone of multiple stacking directivity. In this paper,author uses an accurate multiple residual NMO formula and take hyperbolic curves to fit it by non-linear least square method and draw a set of multiple stacking directivity curves. The average fitting errors are less than 10-5. We use this method to do seismic acquisition and processing in the area with serious multiple interference for the objective zone. We have got very successful results of multiple attenuation in the area and some new oil traps have been found.更多还原