等厚薄互层时频特征的正演模拟
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摘要
本文基于波动理论,利用深度域相移法对不同互层数、不同单层厚度的等厚薄互层进行正演模拟.采用广义S变换分析零偏移距地震道反射复合波的瞬时频谱.研究发现当单层厚度大于3/16波长时,等厚薄互层时域特征为中、高频等幅振荡,瞬时频谱为与单层厚度成反比的单一峰值梳状函数;当单层厚度小于3/16波长时,震源子波的有限带宽对瞬时频谱的高频频率峰有压制作用,导致等厚薄互层中部的时域振幅和频域最大幅度均为低值,薄互层的结构特征不易分辨,说明宽高频的震源子波是提高薄互层分辨能力的关键.此外,理论推导和实验分析均证明:当地层厚度大于1/8波长时,其峰值频率与薄互层单层厚度存在定量解析关系,这为等厚薄互层单层厚度定量预测提供了重要的技术手段.
The isopachous thin interbeddings with different single layer thicknesses and different layer numbers are modeled by phase-shift method based on wave theory.The time-frequency responses of reflection composite wavelet from zero-offset trace are analyzed by generalized S transform.The time domain responses of isopachous thin interbedding are a kind of medium-high frequency equal amplitude oscillation when the single layer thickness is more than 3/16 wavelength.The instantaneous frequency spectrum is a Dirac comb function with single frequency peak that has an inverse relation to the single layer thickness.The single high frequency peak of instantaneous frequency spectrum is suppressed by the source wavelet spectrum which has a limited frequency band width when the layer thickness is less than 3/16 wavelength.Therefore the time domain amplitude and maximum amplitude in frequency spectrum are extremely low so that the structural features of isopachous thin interbedding can not be discriminated easily.Thus,wide-band high frequency source wavelet is the key to improve the resolving power of thin interbedding.Furthermore,the theoretical derivation and experimental analysis show that the main peak frequency has a quantitative analytical relation with the single layer thickness of reflection composite wavelet when the single layer thickness is more than 1/8 wavelength.So it can give a technological mean for predicting single layer thickness quantitatively.
The isopachous thin interbeddings with different single layer thicknesses and different layer numbers are modeled by phase-shift method based on wave theory.The time-frequency responses of reflection composite wavelet from zero-offset trace are analyzed by generalized S transform.The time domain responses of isopachous thin interbedding are a kind of medium-high frequency equal amplitude oscillation when the single layer thickness is more than 3/16 wavelength.The instantaneous frequency spectrum is a Dirac comb function with single frequency peak that has an inverse relation to the single layer thickness.The single high frequency peak of instantaneous frequency spectrum is suppressed by the source wavelet spectrum which has a limited frequency band width when the layer thickness is less than 3/16 wavelength.Therefore the time domain amplitude and maximum amplitude in frequency spectrum are extremely low so that the structural features of isopachous thin interbedding can not be discriminated easily.Thus,wide-band high frequency source wavelet is the key to improve the resolving power of thin interbedding.Furthermore,the theoretical derivation and experimental analysis show that the main peak frequency has a quantitative analytical relation with the single layer thickness of reflection composite wavelet when the single layer thickness is more than 1/8 wavelength.So it can give a technological mean for predicting single layer thickness quantitatively.
引文
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[2]Kallweitt R S,Wood L C.The limits of resolution of zero-phase wavelets.Geophysics,1982,47(7):1035-1046.
[3]苏盛甫.薄储集层的反射特征和定量解释方法.石油地球物理勘探,1988,23(4):387-402.Su S F.Thin-reservoir reflection and the quantitativeinterpretation method.Oil Geophysical Prospecting(in Chinese),1988,23(4):387-402.
[4]Gochioco L M.Modeling studies of interference reflections inthin layered media bounded by coal seams.Geophysics,1992,57(9):1209-1216.
[5]Gochioco L M.Tuning effect and interference reflectionsfrom thin beds and coal seams.Geophysics,1991,56(8):1288-1295.
[6]De Voogd N,den Rooijen H.Thin-layer response andspectral bandwidth.Geophysics,1983,48(1):12-18.
[7]孙鲁平,郑晓东,首皓等.薄层地震峰值频率与厚度关系研究.石油地球物理勘探,2010,45(2):254-259.Sun L P,Zheng X D,Shou H,et al.The studies onrelationship between thin-layer seismic peak frequency and itsthickness.Oil Geophysical Prospecting(in Chinese),2010,45(2):254-259.
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[9]凌云研究小组.应用振幅的调谐作用探测地层厚度小于1/4波长地质目标.石油地球物理勘探,2003,38(3):268-274.Ling Yun Study Group.Application of amplitude tuning insurveying geologic target thickness less than 1/4wavelength.Oil Geophysical Prospecting(in Chinese),2003,38(3):268-274.
[10]Chung H M,Lawton D C.Frequency characteristics ofseismic reflections from thin beds.Canadian Journal ofExploration Geophysics,1995,31(1-2):32-37.
[11]凌云研究组.地震分辨率极限问题的研究.石油地球物理勘探,2004,39(4):435-442.Ling Yun Research Group.Study of seismic resolution limit.Oil Geophysical Prospecting(in Chinese),2004,39(4):435-442.
[12]Lange J N,Almoghrabi H A.Lithology discrimination forthin layers using wavelet signal parameters.Geophysics,1988,53(12):1512-1519.
[13]Koefoed O,De Voogd N.The linear properties of thinlayers,with an application to synthetic seismograms over coalseams.Geophysics,1980,45(8):1254-1268.
[14]Zeng H L.How thin is a thin bed?An alternativeperspective.The Leading Edge,2009,28(10):1192-1197.
[15]Marangakis A,Costain J K,Coruh C.Use of integratedenergy spectra for thin-layer recognition.Geophysics,1985,50(3):495-500.
[16]Robertson J D,Nogami H H.Complex seismic trace analysisof thin beds.Geophysics,1984,49(4):344-352.
[17]Okaya D A.Spectral properties of the earth’s contribution toseismic resolution.Geophysics,1995,60(1):244-251.
[18]李雪英,陈树民,王建民等.薄层时频特征的正演模拟.地球物理学报,2012,55(10):3410-3419.Li X Y,Chen S M,Wang J M,et al.Forward modelingstudies on the time-frequency characteristics of thin layers.Chinese J.Geophys.(in Chinese),2012,55(10):3410-3419.
[19]黄文锋,姚逢昌,李宏兵.薄互层调谐规律研究与净厚度估算.石油地球物理勘探,2012,47(4):584-591.Huang W F,Yao F C,Li H B.Regularities of tuning effectsof thin interbedded layers and their net thickness determination.Oil Geophysical Prospecting(in Chinese),2012,47(4):584-591.
[20]高静怀,陈文超,李幼铭等.广义S变换与薄互层地震响应分析.地球物理学报,2003,46(4):526-532.Gao J H,Chen W C,Li Y M,et al.Generalized S transformand seismic response analysis of thin interbeds.Chinese J.Geophys.(in Chinese),2003,46(4):526-532.
[21]张玉芬,熊维纲.石油地震勘探中薄互层的反射系数序列振幅谱特征分析.地球科学——中国地质大学学报,1994,19(5):685-693.Zhang Y F,Xiong W G.Characteristic analysis of amplitudespectra of reflection coefficient of thin interbedding in oilprospecting.Earth Science—Journal of China University ofGeosciences(in Chinese),1994,19(5):685-693.
[22]赵晨光.薄互层地震反射波的特征分析.石油地球物理勘探,1986,21(1):32-46.Zhao C G.The analysis of seismic reflection from thininterbedding.Oil Geophysical Prospecting(in Chinese),1986,21(1):32-46.
[23]崔凤林,管叶君.时频分析——薄互层结构研究的新途径.石油物探,1992,31(2):1-15.Cui F L,Guan Y J.Time-frequency analysis——a new wayfor thin interbeds examination.Geophysical Prospecting forPetroleum(in Chinese),1992,31(2):1-15.
[24]凌云,郭向宇,高军等.油藏地球物理面临的技术挑战与发展方向.石油物探,2010,49(4):319-336.Ling Y,Guo X Y,Gao J,et al.The technical challenges onthe development trend of reservoir geophysics.GeophysicalProspecting for Petroleum(in Chinese),2010,49(4):319-336.
[25]Knapp R W.Vertical resolution of thick beds,thin beds,andthin-bed cyclothems.Geophysics,1990,55(9):1183-1190.
[26]黄绪德.薄层陷频法.勘探地球物理进展,2002,25(5):1-6.Huang X D.Discussion on notches-in-thin-bed.Progress inExploration Geophysics(in Chinese),2002,25(5):1-6.
[27]Partyka G A,Gridley J M,Lopez J.Interpretationalapplications of spectral decomposition in reservoir characterization.The Leading Edge,1999,18(3):353-360.
[2]Kallweitt R S,Wood L C.The limits of resolution of zero-phase wavelets.Geophysics,1982,47(7):1035-1046.
[3]苏盛甫.薄储集层的反射特征和定量解释方法.石油地球物理勘探,1988,23(4):387-402.Su S F.Thin-reservoir reflection and the quantitativeinterpretation method.Oil Geophysical Prospecting(in Chinese),1988,23(4):387-402.
[4]Gochioco L M.Modeling studies of interference reflections inthin layered media bounded by coal seams.Geophysics,1992,57(9):1209-1216.
[5]Gochioco L M.Tuning effect and interference reflectionsfrom thin beds and coal seams.Geophysics,1991,56(8):1288-1295.
[6]De Voogd N,den Rooijen H.Thin-layer response andspectral bandwidth.Geophysics,1983,48(1):12-18.
[7]孙鲁平,郑晓东,首皓等.薄层地震峰值频率与厚度关系研究.石油地球物理勘探,2010,45(2):254-259.Sun L P,Zheng X D,Shou H,et al.The studies onrelationship between thin-layer seismic peak frequency and itsthickness.Oil Geophysical Prospecting(in Chinese),2010,45(2):254-259.
[8]Marfurt K J,Kirlin R L.Narrow-band spectral analysis andthin-bed tuning.Geophysics,2001,66(4):1274-1283.
[9]凌云研究小组.应用振幅的调谐作用探测地层厚度小于1/4波长地质目标.石油地球物理勘探,2003,38(3):268-274.Ling Yun Study Group.Application of amplitude tuning insurveying geologic target thickness less than 1/4wavelength.Oil Geophysical Prospecting(in Chinese),2003,38(3):268-274.
[10]Chung H M,Lawton D C.Frequency characteristics ofseismic reflections from thin beds.Canadian Journal ofExploration Geophysics,1995,31(1-2):32-37.
[11]凌云研究组.地震分辨率极限问题的研究.石油地球物理勘探,2004,39(4):435-442.Ling Yun Research Group.Study of seismic resolution limit.Oil Geophysical Prospecting(in Chinese),2004,39(4):435-442.
[12]Lange J N,Almoghrabi H A.Lithology discrimination forthin layers using wavelet signal parameters.Geophysics,1988,53(12):1512-1519.
[13]Koefoed O,De Voogd N.The linear properties of thinlayers,with an application to synthetic seismograms over coalseams.Geophysics,1980,45(8):1254-1268.
[14]Zeng H L.How thin is a thin bed?An alternativeperspective.The Leading Edge,2009,28(10):1192-1197.
[15]Marangakis A,Costain J K,Coruh C.Use of integratedenergy spectra for thin-layer recognition.Geophysics,1985,50(3):495-500.
[16]Robertson J D,Nogami H H.Complex seismic trace analysisof thin beds.Geophysics,1984,49(4):344-352.
[17]Okaya D A.Spectral properties of the earth’s contribution toseismic resolution.Geophysics,1995,60(1):244-251.
[18]李雪英,陈树民,王建民等.薄层时频特征的正演模拟.地球物理学报,2012,55(10):3410-3419.Li X Y,Chen S M,Wang J M,et al.Forward modelingstudies on the time-frequency characteristics of thin layers.Chinese J.Geophys.(in Chinese),2012,55(10):3410-3419.
[19]黄文锋,姚逢昌,李宏兵.薄互层调谐规律研究与净厚度估算.石油地球物理勘探,2012,47(4):584-591.Huang W F,Yao F C,Li H B.Regularities of tuning effectsof thin interbedded layers and their net thickness determination.Oil Geophysical Prospecting(in Chinese),2012,47(4):584-591.
[20]高静怀,陈文超,李幼铭等.广义S变换与薄互层地震响应分析.地球物理学报,2003,46(4):526-532.Gao J H,Chen W C,Li Y M,et al.Generalized S transformand seismic response analysis of thin interbeds.Chinese J.Geophys.(in Chinese),2003,46(4):526-532.
[21]张玉芬,熊维纲.石油地震勘探中薄互层的反射系数序列振幅谱特征分析.地球科学——中国地质大学学报,1994,19(5):685-693.Zhang Y F,Xiong W G.Characteristic analysis of amplitudespectra of reflection coefficient of thin interbedding in oilprospecting.Earth Science—Journal of China University ofGeosciences(in Chinese),1994,19(5):685-693.
[22]赵晨光.薄互层地震反射波的特征分析.石油地球物理勘探,1986,21(1):32-46.Zhao C G.The analysis of seismic reflection from thininterbedding.Oil Geophysical Prospecting(in Chinese),1986,21(1):32-46.
[23]崔凤林,管叶君.时频分析——薄互层结构研究的新途径.石油物探,1992,31(2):1-15.Cui F L,Guan Y J.Time-frequency analysis——a new wayfor thin interbeds examination.Geophysical Prospecting forPetroleum(in Chinese),1992,31(2):1-15.
[24]凌云,郭向宇,高军等.油藏地球物理面临的技术挑战与发展方向.石油物探,2010,49(4):319-336.Ling Y,Guo X Y,Gao J,et al.The technical challenges onthe development trend of reservoir geophysics.GeophysicalProspecting for Petroleum(in Chinese),2010,49(4):319-336.
[25]Knapp R W.Vertical resolution of thick beds,thin beds,andthin-bed cyclothems.Geophysics,1990,55(9):1183-1190.
[26]黄绪德.薄层陷频法.勘探地球物理进展,2002,25(5):1-6.Huang X D.Discussion on notches-in-thin-bed.Progress inExploration Geophysics(in Chinese),2002,25(5):1-6.
[27]Partyka G A,Gridley J M,Lopez J.Interpretationalapplications of spectral decomposition in reservoir characterization.The Leading Edge,1999,18(3):353-360.
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