兴安岭山地低信噪比地震资料处理技术分析

大、小兴安岭山地地表大多被火山岩、火山岩风化形成的残余物和腐植土所覆盖，地震资料中普遍存在较强的折射波和多次折射波，资料的信噪比很低；此外，该区低、降速层厚度和速度横向变化剧烈，静校正问题突出，为此，开展了有针对性的处理方法研究。针对山地地表起伏大的特点，采用了浮动基准面方法；针对低、降速层厚度和速度横向变化剧烈的特点，采用了折射静校正和微测井静校正相结合的方法；针对折射波强的特点，采用了t—x域叠前相干压制方法；针对叠加剖面随机噪声严重的特点，采用了f—x域随机噪声衰减方法。实际资料处理表明，采用上述处理手段，提高了资料的信噪比，增强了同相轴的连续性，突出了反射波组特征。

Processing technique for seismic data with low S/N ratio in Xinanlin Mountains

The surface of Daxinanlin Mountains as well as Xiaoxinanlin Mountains is covered with volcanics, volcanoclastic rock and decomposed leaves. Strong refraction and multiple refractions commonly exist in seismic data with a low S/N ratio. In addition, the thickness and velocity of the subweathered zone have great changes laterally, making the static correction very difficult. In order to solve this problem, the following methods were used: 1) the float datum was adopted for radical elevation changes; 2) the combination of the refraction statics and the micro-logging statics was used for the big lateral changes of the thickness and velocity in the subweathered zone and the low velocity layer; 3) the pre-stack coherent noise attenuation in T-X domain was used for strong refraction; 4) the random noise attenuation in F-X domain was applied for the severe random noise of the stack sections. The actual processing shows that the above mentioned processing methods can improve the S/N ratio of the seismic data, enhance the consistency of event, and stress the characteristics of the reflection group.