VTI介质平移初至走时动校正双参数反演  

Shifted first-arrival traveltime NMO velocity and η inversion for VTI media

作　　者：张博[1] 韩立国[1] 谭尘青[1] 黄飞[1] 张生强[1] 

机构地区：[1]吉林大学地球探测科学与技术学院,吉林长春130026

出　　处：《石油物探》2012年第2期119-124,132,共7页Geophysical Prospecting For Petroleum

基　　金：国家自然科学基金项目(41074075/D0409);国土资源部公益性行业科研专项(201011047-2)联合资助

摘　　要：VTI介质浅层长偏移距动校正一直是地震资料处理的难点之一,常规校正后同相轴不仅出现强烈拉伸,常见的信号交错更会造成同相轴扭曲,即便采用高精度非双曲线走时公式也无法将精度范围内的信号正确校正。为此,首先采用重建的同一信号周期内各信号点的走时公式,通过初至点走时将信号整体搬家,消除动校拉伸;然后利用基于初至点走时的双参数反演方法,对传统的相似系数算法公式进行改进。通过对水平3层VTI介质理论模型试算的结果表明,平移初至整体搬家方法能将长偏移距同相轴无拉伸校平;而初至点双参数反演方法能够大幅提升反演的精度。Long-offset NMO correction of shallow layers in vertical transversely isotropic media(VTI) is always one of the difficulties in seismic data processing.After conventional NMO correction,the seismic events are strongly stretched.Moreover,common signal interlacing even causes the distortion of seismic events and the signals within the accuracy range cannot be corrected even by applying high-precision non-hyperbolic traveltime formula.Therefore,shifted first-arrival traveltime NMO velocity and η inversion for VTI media was proposed.Firstly,after reconstructing the traveltime formula of all signal points in a signal period,based on the traveltime of first-arrival points,we carry out whole shifting of signals to remove NMO stretching.Then,shifted first-arrival traveltime NMO velocity and η inversion for VTI media was used to improve the traditional similarity coefficient formula.Three-layer VTI model testing result indicates that shifted first-arrival traveltime NMO can correct long-offset events without stretching,and velocity and η inversion at first-arrival points can largely improve the accuracy of inversion.

关 键 词：VTI 长偏移距 初至点 速度分析 双参数反演 

分 类 号：P631.4[天文地球—地质矿产勘探]