复杂地形深地震反射数据采集参数优化  

Optimization of data acquisition parameters for deep seismic reflection surveys in complex terrain

作　　者：晏云翔 李培[2] 智敏 刘建达 王子琛 张颖[2] 裴跟弟 李林元 牟棋 贾晋 YAN Yunxiang;LI Pei;ZHI Min;LIU Jianda;WANG Zichen;ZHANG Ying;PEI Gendi;LI Linyuan;MOU Qi;JIA Jin(CCTEG Xi’an Research Institute(Group)Co.,Ltd.,Xi’an 710077,China;Fujian Earthquake Agency,Fuzhou 350003,China)

机构地区：[1]中煤科工西安研究院(集团)有限公司,陕西西安710077 [2]福建省地震局,福建福州350003

出　　处：《煤田地质与勘探》2023年第12期83-92,共10页Coal Geology & Exploration

基　　金：中煤科工西安研究院(集团)有限公司科技创新项目(2022XAYJS07)。

摘　　要：福建地处中国东南沿海造山带区域,构造发育,地表条件复杂,深地震反射探测难度大。针对探测区地震地质条件多样性和复杂性的特点,在以往深地震探测实践基础上,将“大、中、小”炮组合激发方式优化为常规炮(炮点距600 m)与大炮(炮点距15 km)结合的炮点布置方式,提高大炮的覆盖次数;模拟分析并计算了组合井间距,使激发能量更为集中并产生最大效能的地震弹性波;将节点式地震仪的主频10 Hz优化为5 Hz进行数据采集,提高原始地震数据中−深部分辨率;将接收道数由1200道优化为2400道,使最大炮检距达到了36 km,超过探测区莫霍面深度,获得了更深部的反射信息。地震采集参数优化后,获得的原始单炮记录和初叠时间剖面信噪比高,地壳中、深部以及莫霍面反射波显示清晰,地壳结构成像精度高,达到了预期的地质效果。获得的采集参数能够为类似地区开展深地震反射探测提供参考。Fujian,located in the orogen region of the coastal areas of southeast China,exhibits well-developed structures and complex surface conditions,which make deep seismic reflection surveys challenging.In response to the diversity and complexity of seismogeological conditions in Fujian,this study optimized the seismic excitation means based on previous deep seismic surveys.Specifically,the combination of large,medium,and small guns was transitioned into the layout of normal guns(spacing of shot points:600 m)and large shots(spacing of shot points:15 km),leading to enhanced folds of large shots.Through simulation analysis,this study calculated the spacing of combined boreholes,aiming to concentrate the excitation energy and generate seismic elastic waves with the maximum efficiency.It optimized the dominant frequency of the nodal seismometers for data acquisition,reducing it from 10 Hz to 5 Hz to improve the resolution of data on the middle-deep crust in seismic records.Furthermore,this study increased the number of receiving channels from 1200 to 2400,achieving a maximum offset of 36 km.This value exceeds the depth of the Moho in Fujian,allowing for the acquisition of the reflection signals of deeper parts.After the optimization of the seismic acquisition parameters,the obtained original single-shot seismic records and initially stacked time sections featured high signalto-noise ratios.The optimization also contributed to clear reflected waves of the middle-deep crust and the Moho,as well as high imaging accuracy of the crustal structure.As a result,the expected geological survey effects were achieved.The newly obtained data parameters can provide a reference for deep seismic reflection surveys in similar areas.

关 键 词：复杂地形 深地震反射 采集参数 观测系统 莫霍面 福建 

分 类 号：P631[天文地球—地质矿产勘探]