共反射元弧叠加方法在火山岩成像中的应用

APPLICATION OF SEISMIC DATA COMMON REFLECTION ARC STACK METHOD IN IMAGING OF IGNEOUS ROCKS

常规叠加方法假设叠加的地震道集的反射波来自地下同一个反射点 ,而地表观测到的反射波场在空间上小于菲涅尔体范围是不可分辨的 .本文根据火山岩体特征 ,用元弧描述火山岩的反射界面 .将来自菲涅尔体范围内的反射波沿着元弧界面求和 ,进而扩大叠加次数 ,达到增加反射信号能量提高地震反射波的叠加成像质量的目的 .文中给出了反射波走时参数与地下元弧反射界面之间的联系和叠加实现的步骤 .计算结果表明 ,元弧叠加方法能够提高剖面的信噪比 。

In conventional stack methods, reflection events in stack gather are generally assumed to come from the same reflective points. Whereas the received reflective wavefield is indistinguishable when its scope is less than the Fresnel's. Based on the characteristics of lava, an arc is used to describe the reflective interface. Along the arc interface, reflections coming from Fresnel zone are summed. So the number of coverage is enhanced greatly. The aim for increasing the energy of signal and improving the quality of stack images is also met. The relation between parameters of travel time and the interfaces of arc subsurface is presented . The steps of stacking are also shown. Computed results show that the method of arc stacking can effectively increase both the ratio of signal to noise in section and the continuity of reflective events.