VTI介质平移初至走时动校正双参数反演
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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.
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.
引文
[1]尤建军,常旭,刘伊克.VTI介质长偏移距非双曲动校正公式优化[J].地球物理学报,2006,71(6):1770-1778 You J J,Chang X,Liu Y K.Optimization of nonhy-perbolic moveout correction equation of long offset seismic data in VTI media[J].Geophysics,2006,71(6):1770-1778
[2]Tsvankin T.Nonhyperbolic reflection moveout in anisotropic media[J].Geophysics,1994,59(8):1290-1304
[3]Alkhalifah T,Tsvankin I.Velocity analysis for transversely isotropic media[J].Geophysics,1995,60(5):1550-1566
[4]Vladimir G,Tsvankin I.Feasibility of nonhyperbolic moveout inversion in transversely isotropic media[J].Geophysics,1998,63(3):957-969
[5]薛冈,王良书,胡中平.大炮检距地震资料动校正方法比较[J].石油地球物理勘探,2003,38(2):151-155 Xue G,Wang L S,Hu Z P.Comparison between nor-mal moveout(NMO)methods for long-offset seismic data[J].Oil Geophysical Prospecting,2003,38(2):151-155
[6]尤建军,陈强,张超谟,等.各向同性介质长偏移距地震同相轴动校正[J].地球物理学进展,2008,23(4):1173-1178 You J J,Cheng Q,Zhang C M,et al.NMO correction of long-spread seismic events in homogeneous and i-sotropic media[J].Progress in Geophysics,2008,23(4):1173-1178
[7]夏洪瑞,葛川庆,邹少锋.具有截断误差校正的广角反射NMO校正方法[J].石油物探,2005,44(2):154-157 Xia H R,Ge Q C,Zou S F.NMO method of wide an-gle reflection with truncation error correction[J].Geophysical Prospecting for Petroleum,2005,44(2):154-157
[8]夏洪瑞,葛川庆.误差均值法实现广角反射NMO校正[J].石油地球物理勘探,2005,40(4):381-385 Xia H R,Ge C Q.NMO correction of wide-angle re-flection by mean errors value method[J].Oil Geo-physical Prospecting,2005,40(4):381-385
[9]马在田,夏凡,杨锴.提高反射地震成像分辨率的方法及应用[J].天然气工业,2005,25(9):29-32 Ma Z T,Xia F,Yang K.Method of enhancing reflec-tion seismic imaging resolution and its application[J].Natural Gas Industry,2005,25(9):29-32
[10]邬达理.一种改善长排列地震资料分辨率的处理方法[J].石油物探,2005,44(5):465-567 Wu D L.A processing method to improve the seis-mic resolution on expanding spread[J].Geophysical Prospecting for Petroleum,2005,44(5):465-567
[11]Rupert G B,Chun J H.The block move sum normal moveout correction[J].Geophysics,1975,40(1):17-24
[12]Shatilo A,Aminzadeh F.Constant normal-moveout(CNMO)correction:a technique and test results[J].Geophysical Prospecting,2000,48(3):473-488
[13]李录明.无畸变浅层地震资料动校正[J].石油物探,1991,30(4):81-88 Li L M.Undistorted dynamic correction for seismic data from shallow reflectors[J].Geophysical Pros-pecting for Petroleum,1991,30(4):81-88
[14]Tan C Q,Wu Y G,Han L G,et al.Shifted first arri-val point travel time NMO inversion[J].AppliedGeophysics,2011,8(3):217-224
[15]Thomsen L.Weak elastic anisotropic[J].Geophys-ics,1986,51(10):1954-1966
[16]Aleixo R,Schleicher J.Traveltime approximations for P waves in vertical transversely isotropic media[J].Geophysical Prospecting,2010,58(2):191-201
[17]Fomel S.On anelliptic approximations for qP veloci-ties inVTI media[J].Geophysical Prospecting,2004,52(3):247-259
[2]Tsvankin T.Nonhyperbolic reflection moveout in anisotropic media[J].Geophysics,1994,59(8):1290-1304
[3]Alkhalifah T,Tsvankin I.Velocity analysis for transversely isotropic media[J].Geophysics,1995,60(5):1550-1566
[4]Vladimir G,Tsvankin I.Feasibility of nonhyperbolic moveout inversion in transversely isotropic media[J].Geophysics,1998,63(3):957-969
[5]薛冈,王良书,胡中平.大炮检距地震资料动校正方法比较[J].石油地球物理勘探,2003,38(2):151-155 Xue G,Wang L S,Hu Z P.Comparison between nor-mal moveout(NMO)methods for long-offset seismic data[J].Oil Geophysical Prospecting,2003,38(2):151-155
[6]尤建军,陈强,张超谟,等.各向同性介质长偏移距地震同相轴动校正[J].地球物理学进展,2008,23(4):1173-1178 You J J,Cheng Q,Zhang C M,et al.NMO correction of long-spread seismic events in homogeneous and i-sotropic media[J].Progress in Geophysics,2008,23(4):1173-1178
[7]夏洪瑞,葛川庆,邹少锋.具有截断误差校正的广角反射NMO校正方法[J].石油物探,2005,44(2):154-157 Xia H R,Ge Q C,Zou S F.NMO method of wide an-gle reflection with truncation error correction[J].Geophysical Prospecting for Petroleum,2005,44(2):154-157
[8]夏洪瑞,葛川庆.误差均值法实现广角反射NMO校正[J].石油地球物理勘探,2005,40(4):381-385 Xia H R,Ge C Q.NMO correction of wide-angle re-flection by mean errors value method[J].Oil Geo-physical Prospecting,2005,40(4):381-385
[9]马在田,夏凡,杨锴.提高反射地震成像分辨率的方法及应用[J].天然气工业,2005,25(9):29-32 Ma Z T,Xia F,Yang K.Method of enhancing reflec-tion seismic imaging resolution and its application[J].Natural Gas Industry,2005,25(9):29-32
[10]邬达理.一种改善长排列地震资料分辨率的处理方法[J].石油物探,2005,44(5):465-567 Wu D L.A processing method to improve the seis-mic resolution on expanding spread[J].Geophysical Prospecting for Petroleum,2005,44(5):465-567
[11]Rupert G B,Chun J H.The block move sum normal moveout correction[J].Geophysics,1975,40(1):17-24
[12]Shatilo A,Aminzadeh F.Constant normal-moveout(CNMO)correction:a technique and test results[J].Geophysical Prospecting,2000,48(3):473-488
[13]李录明.无畸变浅层地震资料动校正[J].石油物探,1991,30(4):81-88 Li L M.Undistorted dynamic correction for seismic data from shallow reflectors[J].Geophysical Pros-pecting for Petroleum,1991,30(4):81-88
[14]Tan C Q,Wu Y G,Han L G,et al.Shifted first arri-val point travel time NMO inversion[J].AppliedGeophysics,2011,8(3):217-224
[15]Thomsen L.Weak elastic anisotropic[J].Geophys-ics,1986,51(10):1954-1966
[16]Aleixo R,Schleicher J.Traveltime approximations for P waves in vertical transversely isotropic media[J].Geophysical Prospecting,2010,58(2):191-201
[17]Fomel S.On anelliptic approximations for qP veloci-ties inVTI media[J].Geophysical Prospecting,2004,52(3):247-259
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