基于倾角中值滤波法的浅层反射地震叠前信噪分离技术

Shallow Reflection Seismic Prestack Noise Separation Technology Based on Dip Median Filtering Method

浅层反射地震资料中面波一般比较发育,对有效信号形成干扰,现有压制面波等相干干扰的处理手段主要适用于中深部、深部地震勘探,但并不适用于浅层反射地震资料的处理,为此提出了倾角中值滤波法。该方法是基于叠前地震单炮道集上反射波与强线性干扰在t-x域视速度上的差异,在多组视倾角范围内,求取一个最佳视倾角,将最佳视倾角的振幅序列的中值视为相干干扰,利用"减去法",达到信噪分离。通过模型与实际资料的处理,证明该方法能够有效分离强线性干扰,并保留了强线性干扰的特性,提高了资料的信噪比,保真度高,是浅层高分辨率地震勘探的一种理想的叠前信噪分离技术。

The surface wave is generally more developed in the shallow reflection seismic data, and causing interferences on effective signals. Available means to suppress this kind of coherent interferences such as surface wave is mainly applicable to medium and deep part seismic prospecting, not adequate for shallow reflection seismic data processing. For this reason, the dip median filtering method puts forward. The method is based on t-x domain apparent velocity difference between reflection wave and strong linear interference s on prestack seismic single-shot trace gather. It is achieved by following： firstly to obtain the optimum value from many groups of apparent dip angle, then to take the mid-value as a coherent sequence of interference, finally to subtract the mid-value to reach the noise separation. This method can effectively both separating strong linear interference, and retaining features to improve the data signal to noise ratio, high fidelity, so it is an ideal prestack noise separation technology of high-resolution shallow seismic survey.