应用VSP观测的黄土塬地面地震干扰波研究  

Study of surface seismic interference wave in loess tableland based on VSP observation

作　　者：闫有平 赵军才 胡亚东 高峻 谭勇 王云朋 YAN Youping;ZHAO Juncai;HU Yadong;GAO Jun;TAN Yong;WANG Yunpeng(Huabei Branch Company of SINOPEC Petroleum Engineering Geophysical Corporation,Zhengzhou,Henan 450000,China)

机构地区：[1]中石化石油工程地球物理有限公司华北分公司,河南郑州450000

出　　处：《石油地球物理勘探》2022年第5期1046-1056,I0002-I0003,共13页Oil Geophysical Prospecting

基　　金：中石化地球物理公司科研项目“井—地联合多波多分量地震资料采集、处理、解释一体化技术”(SGC-2020-0209)与“黄土塬地震勘探关键技术与工艺研究”(SGC-2021-09)联合资助。

摘　　要：地表条件复杂的黄土塬区地震记录中干扰波类型众多,尤其是一种俗称“八字胡”的干扰波,严重影响有效反射波,且在后续处理中难以去除。研究其形成机理、所属类型,可为前期数据采集方案设计及后续去噪(该干扰波)处理流程制订提供依据。文中首先分析了地震记录中“八字胡”干扰波的频率、能量、时距曲线及速度等特征,认为它是一种折射波,其波场类型可能为横波;由于该干扰波在地面地震记录中为上行波,VSP观测可记录其下行波,因此通过分析区内VSP记录中相应下行波场的偏振、源点及频率等特点,确定它为纯横波;再利用Walkaway VSP实际记录及非纵近排列模拟记录做进一步验证,判定该“八字胡”干扰波为纯横波折射波。The interference waves in the seismic records of loess tableland areas with complex surface conditions are of various types.In particular,the kind of interference wave commonly known as“handlebar mustache”seriously affects effective reflected waves and is difficult to remove in subsequent processing.Studying the formation mechanism and the type of this interference wave can provide a basis for the design of a data acquisition scheme in the early stage and the formulation of a processing flow for subsequent denoising(of this interference wave).This paper starts with analyzing the frequency,energy,traveltime-distance curve,and velocity of the“handlebar mustache”interference wave in the seismic records,concluding that it is a refracted wave and its wavefield is likely to be one of a shear wave.Since this interference wave is an upgoing wave in the field seismic record and vertical seismic profile(VSP)observation can record its downgoing wave,it is determined to be a pure shear wave by analyzing the polarization,source,and frequency of the wavefield of the corresponding downgoing wave in the VSP record of the area.Further verification by actual Walkaway VSP records and off-line near-spread simulation records is conducted,and the“handlebar mustache”interference wave is determined to be a purely shear refracted wave.

关 键 词：黄土塬 八字胡 VSP 极化分析 纯横波 折射波 

分 类 号：P631[天文地球—地质矿产勘探]