Experiments on excitation and data processing of low-frequency vibroseis in permafrost area of the tibetan plateau  

青藏高原冻土区低频可控震源激发及数据处理试验

作　　者：Tian Yu-Kun Kang Hai-xia Cao Jie Li Juan Zhou Hui Ma Yan-Yan 田玉昆;康海霞;曹洁;李娟;周惠;马彦彦(中国地质调查局油气资源调查中心非常规油气地质重点实验室,北京100029)

机构地区：[1]OGS,CGS,Beijing 100083,China

出　　处：《Applied Geophysics》2020年第5期834-843,904,共11页应用地球物理（英文版）

基　　金：This work was supported by Nation key R&D program(No.2016YFC060110305);Geological and mineral investigation and evaluation special project(No.DD20160160 and No.DD20160181).

摘　　要：Few seismic exploration work was carried out in Tibetan Plateau due to the characteristics of alpine hypoxia and harsh environmental protection needs.Complex near surface geological conditions,especially the signal shielding and static correction of permafrost make the quality of seismic data is not ideal,the signal to noise ratio(SNR)is low,and deep target horizon imaging is difficult.These data cannot provide high quality information for oil and gas geological survey and structural sedimentary research in the area.To solve the issue of seismic exploration in Tibetan Plateau,this test used low frequency vibroseis wide-line and high-density acquisition scheme.In view of the actual situation of the study area,the terrain,the source and the diff erent observation system were simulated,and the processing technique was adopted to improve the quality of seismic data.Low-frequency components with a minimum of 1.5Hz of vibroseis ensure the deep geological target imaging quality in the area,the seismic profi le wave group is clear,and the SNR is relatively high,which can meet the needs of oil and gas exploration.Seismic data can provide the support for the development of oil and gas survey in the Tibet plateau.青藏高原地区因其高寒缺氧、环保需要等特点,鲜有地震勘探工作开展。又因其地质条件复杂,湖泊和沼泽广布,尤其存在永久冻土层,少量开展的地震勘探工作所获资料品质不尽理想,无法为该地区的油气地质调查和构造沉积研究提供高品质资料。究其原因,主要在于冻土层带来的信号屏蔽和静校正问题,使得地震数据信噪比不高,深层成像困难。为解决青藏高原地震勘探的难题,本次试验采用低频可控震源高密度宽线采集方案,针对研究区实际情况开展地形、震源和不同观测系统的正演模拟,采用针对性的处理技术,提高了地震数据的质量。低至1.5 Hz的低频成分,保证了该地区深部成像质量,地震剖面波组特征清楚,信噪比较高,能够满足油气勘探需要,为开展青藏高原油气调查有利区优选工作提供数据支持。

关 键 词：Tibetan Plateau permafrost region low frequency vibroseis wide-line and high-density 2D seismic static correction noise attenuation 

分 类 号：P631.4[天文地球—地质矿产勘探]