利用最小二乘自适应滤波实现绕射波分离

Diffracted wave separation by applying self-adaptive least square filtering method

尺度目标体的绕射波能量较弱,常被能量较强的反射波淹没,与反射波一起成像难度较大.因而,实现绕射波成像的核心问题之一为绕射波与反射波分离.通常建立反射波模型的方法有Radon变换等域变换类方法,但该类方法在减去反射波能量上存在问题.为更彻底实现压制反射波目的,本文引入自适应滤波方法,该方法较简单的减去法能更好预测反射波能量.实际资料应用效果表明,最小二乘自适应滤波方法能更好突显单炮记录上绕射波特征,得到的叠加剖面中反射波去除更为彻底干净,偏移剖面中小断层、断点、尖灭点等小尺度地质体成像清晰.

Weak information carried by small scale geologies is commonly suppressed in strong reflection, which makes simultaneously iraaging of both diffracted wave and reflected wave hard to realize. Thus, how to make separation of these two kinds of wave always are the key of diffracted wave imaging techniques. Radon transformation belonging to one kind of domain transformation methods can be taken to model reflected wave. However, there is a problem existing in its simple subtraction way. In order to crack such problem, we apply self adaptive least square method to better model reflection energies. Field data application indicated that the proposed method can make diffracted wave stand out in shot gather and reflection in stacked profile badly suppressed, thus getting small fault, discontinuities, and pinch-out better imaged.