深层地震波吸收机理及能量补偿方法研究
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摘要
随着地震勘探领域向深层化发展,对深层地震资料的质量要求越来越高。为了提高深层地震资料的信噪比和分辨率,我们进行了深层地震波吸收机理,深层去噪和能量补偿方法的研究。
本文首先研究了影响地震波衰减的主要因素,可归纳为以下几个方面:①与地下的地质情况有关的因素,如反射系数、反射界面形状引起的聚焦与发散、地层非弹性引起的地层吸收、薄互层引起的多次反射、地下不均匀体引起的散射等;②与近地表条件有关的因素,如震源强度和耦合情况、检波器灵敏度和耦合情况、近地表松散地层的强烈吸收等;③与炮检距有关的因素,如球面发散、传播路径不同引起的吸收变化等。
要有效补偿深层能量,首先需要提高深层信号的信噪比。本文提出了分割法二维小波变换压制面波方法,较之常规的FK滤波能最大限度地保护了有效波。另外比较了KL变换,f-x预测预测去噪,小波阈值去噪等随机噪声压制方法的优缺点:KL变换去噪对于倾斜和弯曲同相轴压制噪声效果不好,去噪后损失部分信号能量,并降低了信号的分辨率;f-x预测去噪是假定同相轴是线性的,当同相轴不是线性延伸时,使同相轴发生部分畸变;二维小波变换阈值去噪在保持信号能量方面取得较好的效果,去掉的基本上全是噪声,且对信噪比比较低的资料效果也较显著。
针对大地吸收衰减提出了时频分析法能量补偿技术。该方法的最大优点是不需要知道地层的品质因子,这就避开了求取地层吸收系数这一难题,从而使这一方法能够得到广泛应用。模型试算和实际资料试处理证明了这种方法的有效性。
With deep layer becoming the major objective of seismic exploration, high quality seismic data was needed. In order to improve the signal-noise(S/N) ratio and resolution of deep seismic data, deep layer seismic absorption mechanism, deep de-noising technology and energy compensation technology was studied.
This paper studied the main factors influencing seismic wave attenuation, which can be summarized as the following:①The factors related to underground geological conditions, such as the reflection coefficient, the focus and divergence caused by reflection interface shape, absorption arising from the formation of non-elastic formation, multiple reflections caused by thin alternating layers, the scattering caused by inhomogenous;②The relevant factors related to near-surface conditions , such as the strength and coupling of the source, detector sensitivity and coupling, the strong absorption caused by the near-surface stratigraphy loose;③The factors related to offset, such as spherical divergence, absorption changes caused by different transmission path.
In order to enhance signal energy in deep layer, the S/N ratio must be improved. This paper presents a segmentation surface wave suppression using 2-D wavelet transform. Compared with conventional FK filtering, the advantages of this method is to maximize maintain effective wave. In addition, the advantages and disadvantages of the KL transform, f-x forecast de-noising, wavelet threshold de-noising was compared: When the events are horizontal, the conventional KL transform can enhance the events; but when the events are oblique or curving, using the conventional KL transform will destroy the continuity of effective events; F-x forecast de-noising adapt to linear events. When the events are not linear, using f-x forecast de-noising will cause event distortion. 2-D wavelet transform de-noising have good result in maintaining signal energy and suitable to low S/N data.
For the earth attenuation, time-frequency analysis of energy compensation technology has been presented. The biggest advantage of this method is does not need to know the quality of formation, which seek to avoid the formation of this absorption coefficient, so that this method can be widely applied. Model spreadsheet and the actual data processing test proved the validity of the method.
本文首先研究了影响地震波衰减的主要因素,可归纳为以下几个方面:①与地下的地质情况有关的因素,如反射系数、反射界面形状引起的聚焦与发散、地层非弹性引起的地层吸收、薄互层引起的多次反射、地下不均匀体引起的散射等;②与近地表条件有关的因素,如震源强度和耦合情况、检波器灵敏度和耦合情况、近地表松散地层的强烈吸收等;③与炮检距有关的因素,如球面发散、传播路径不同引起的吸收变化等。
要有效补偿深层能量,首先需要提高深层信号的信噪比。本文提出了分割法二维小波变换压制面波方法,较之常规的FK滤波能最大限度地保护了有效波。另外比较了KL变换,f-x预测预测去噪,小波阈值去噪等随机噪声压制方法的优缺点:KL变换去噪对于倾斜和弯曲同相轴压制噪声效果不好,去噪后损失部分信号能量,并降低了信号的分辨率;f-x预测去噪是假定同相轴是线性的,当同相轴不是线性延伸时,使同相轴发生部分畸变;二维小波变换阈值去噪在保持信号能量方面取得较好的效果,去掉的基本上全是噪声,且对信噪比比较低的资料效果也较显著。
针对大地吸收衰减提出了时频分析法能量补偿技术。该方法的最大优点是不需要知道地层的品质因子,这就避开了求取地层吸收系数这一难题,从而使这一方法能够得到广泛应用。模型试算和实际资料试处理证明了这种方法的有效性。
With deep layer becoming the major objective of seismic exploration, high quality seismic data was needed. In order to improve the signal-noise(S/N) ratio and resolution of deep seismic data, deep layer seismic absorption mechanism, deep de-noising technology and energy compensation technology was studied.
This paper studied the main factors influencing seismic wave attenuation, which can be summarized as the following:①The factors related to underground geological conditions, such as the reflection coefficient, the focus and divergence caused by reflection interface shape, absorption arising from the formation of non-elastic formation, multiple reflections caused by thin alternating layers, the scattering caused by inhomogenous;②The relevant factors related to near-surface conditions , such as the strength and coupling of the source, detector sensitivity and coupling, the strong absorption caused by the near-surface stratigraphy loose;③The factors related to offset, such as spherical divergence, absorption changes caused by different transmission path.
In order to enhance signal energy in deep layer, the S/N ratio must be improved. This paper presents a segmentation surface wave suppression using 2-D wavelet transform. Compared with conventional FK filtering, the advantages of this method is to maximize maintain effective wave. In addition, the advantages and disadvantages of the KL transform, f-x forecast de-noising, wavelet threshold de-noising was compared: When the events are horizontal, the conventional KL transform can enhance the events; but when the events are oblique or curving, using the conventional KL transform will destroy the continuity of effective events; F-x forecast de-noising adapt to linear events. When the events are not linear, using f-x forecast de-noising will cause event distortion. 2-D wavelet transform de-noising have good result in maintaining signal energy and suitable to low S/N data.
For the earth attenuation, time-frequency analysis of energy compensation technology has been presented. The biggest advantage of this method is does not need to know the quality of formation, which seek to avoid the formation of this absorption coefficient, so that this method can be widely applied. Model spreadsheet and the actual data processing test proved the validity of the method.
引文
[1]马昭军,刘洋.地震波衰减反演研究综述.地球物理学进展.2005,20(4),1047~1082
[2] Hudson JA, Knopoff L Predicting the overall lproperties of composites materials with small-scale inclusions or cracks[J].PureApplGeophys,1989,131:551~576.
[3] O’Connell R J , Budiansky B.Viscoelaslutic properties of fluid-saturated cracked solids[J].Geophys,Res.1977,82:5719~5735.
[4]尹军杰,刘学伟,李文慧.地震波散射理论及应用研究综述.地球物理学进展,2005,3,20(1): 123~134.
[5]王大兴,辛可锋,李幼铭等.地层条件下砂岩含水饱和度对波速及衰减影响的实验研究.地球物理学报,2006 ,49(3): 908～914
[6] Sothcott J , McCann C, O’Hara S G.. The influence of two different pore fluids on the acoustic properties of reservoir sandstones at sonic and ultrasonic frequencies. 70th Ann. Internat Mtg., Soc. Expi .Geophys. Expanded Abstracts , 2000.
[7] White J E, Boit G, 1986. Theory of extension waves in porousrods. Geophysics, 51 (3) : 742～745
[8] Klimentos T, Maccann C, 1990. Relationships among compressional wave attenuation, porosity, clay content, and per-meability in sandstones. Geophysics, 55 (8) : 998～1014
[9] Grant A G, 1994. Fluid effects on velocity and attenuation in sandstones. J Acoust Soc Amer, 96 (2) : 1 158～1173
[10]席道瑛,邱文亮,程经毅,易良坤,张斌,谢端.饱和多孔岩石的衰减与孔隙率和饱和度的关系.石油地球物理勘探,1997.32(2):196～201
[11]席道瑛,程经毅,张斌等.饱和多孔岩石应力波的衰减特性.地震学报,1997,19(5):457～461
[12]席道瑛.程经毅,席军.饱和砂岩滞弹性弛豫热激活过程机理探讨.石油地球物理勘探,1998,33(3):348一354
[13]席道瑛,刘斌,谢端,刘卫,易良坤,张斌.孔隙流体饱和砂岩的衰减与频率的相关性.石油地球物理勘探,1998,33(1):66-70,77
[14]席道瑛,刘斌,刘卫,易良坤.饱和多孔岩石弛豫衰减对时间和温度的依赖性.地球物理学报,2000,43(6):827～835
[15]席道瑛,刘爱文,刘卫.低频条件下饱和流体砂岩的衰减研究.地震学报,1995,17(4): 585～591
[16]席道瑛等.岩石中应力弛珠的衰减和模且色散.石油物探,1995.34(3)103~108
[17] Shatilo A.P., Sondergeld c.s., Ultrasonic attenuation in Glenn Pool Rocks, northeastern Oklahoma[J].Geophsics, 1998,63:465～478
[18] Jones T.D.,Pore fluids and frequency-dependent wave propagation in rocks[J]. Geophysics,1986,51:1935～1953
[19]席道瑛等.岩石中应力弛珠的衰减和模且色散[J].石油物探, 1995, 34(3): 103~108
[20]孙成禹,地震波动力学理论,石油大学研究生院教材。2003, 4:105~107
[21]胡昌华,张军波,夏军等.基于MATLAB的系统分析与设计——小波分析[M].西安:西安电子科技大学出版社. 2000,P3
[22]张贤达.现代信号处理[M].北京:清华大学出版社. 2002
[23] McFadden, P.D., Cook, J.G., and Forster, L.M., Decomposition of gear vibration signals by the generalized S-transform:Mech.Syst. Signal Process, 1999,13:691~707
[24] Stockwell R.G., MansinhaL, and Lowe R.P. Localization of the complex spectrum: the S transform [J]. IEEE Transactions on Signal Processing, 1996, Vol.44, No.4: 998~1001
[25]陈学华,贺振华.改进的S变换及在地震信号处理中的应用[J].数据采集与处理, 2005, 20(4): 449~453
[26]刘喜武,刘洪,李幼铭,年静波.基于广义S变换研究地震地层特征.球物理学进展, 2006, 21(2): 440~451
[27] Mansinha L, Stockwell R.G., Lowe R.P. Pattern Analysis with two dimensional spectral localization: Application of two dimensional S transform[J]. Physica A, 1997, 239: 286~295.
[28] Pinnegar C R, Mansinha L. The S-Transform With Windows of Arbitrary And Varying Shape[J]. Geophysics, 2003,68 (1): 381~385.
[29]陆基孟.地震勘探原理.东营:石油大学出版社, 1993.1:88~91
[30] Hemon C H , Mace D. Use of t he Karhunen-Loeve t ransformation in seismic data processing . Geophysical Prospecting ,1978 ,26 :600~626.
[31] Jones I.F., Levy S. Signal-to-noise ratio enhancement in multichannel seismic data via the Karhunen-Loeve transform .Geophysical Prospecting, 1987, 35: 12~32.
[32]付燕.人工地震信号去噪方法研究.西北工业大学博士论文,2002:77~79
[33]康冶,于承业,贾卧,王春梅.陈颖f-x域去噪方法研究.石油地球物理勘探,2003, 38(2): 136~138
[34]蔡加铭,周兴元,吴律.f-x域算子外推去噪技术研究[J].石油地球物理勘探,1999,34(3):325~331.
[35]国九英.叠前ω-x域算子外推法去噪[J].石油地球物理勘探,1995,30(4):487~494
[36]俞寿朋.地震信号的多项式拟合在偏移前资料处理中的应用[J].物探科技通报,1988, 6(1): 6~18.
[37]俞寿朋,蔡希铃.用地震信号多项式拟合提高叠加剖面信噪比[J].石油地球物理勘探, 1988,23(2):131～139.
[38]周怀来.基于小波变换的地震信号去噪方法研究与应用.成都理工大学硕士学位论文,2006
[39]邱庚香,熊彬,梁锦文.应用小波变换提高浅层地震记录分辨率[J].桂林工学院学报. 2003, 23(2): 159~164.
[40] Donoho D L. De_noising via soft-thresholding [J]. IEEE Trans on Information Theory , 1992 , 41 (3) : 613~627.
[41]李庆武,陈小刚.小波阈值去噪的一种改进方法.光学技术,2006,32(6):831~833.
[42] Bickel, S.H., and Natarajan, R.R., Plane-wave Q deconvolution[J]. Geophysics, 1985, 50: 1426~1439.
[43] Hargreaves,N.D., and Calvert, A.J. Inverse Q filtering by Fourier transform: Geophysics[J], 1991,56: 519~527
[44]裴江云,何樵登.基于Kjartansson模型的反Q滤波[J].地球物理学进展. 1994, 9(1):90~100
[45] Yanghua Wang. A stable and efficient approach of inverse Q filtering[J]. Geophysics, 2002, 67(2): 657~664
[46] Yanghua Wang. Inverse Q-filter for seismic resolution enhancement[J]. Geophysics, 2006 ,71(3):v51~v61
[47]白桦,李级鹏.基于时频分析的地层吸收补偿.石油地球物理勘探, 1999, 34(6):642~648
[48]李鲲鹏,李衍达,张学工。基于小波包分解的地层吸收补偿。地球物理学报,2000,43(4):542~549
[49]刘喜武,年静波,刘洪。基于广义S变换的吸收衰减补偿方法。石油物探,2006,45(1):9~14
[2] Hudson JA, Knopoff L Predicting the overall lproperties of composites materials with small-scale inclusions or cracks[J].PureApplGeophys,1989,131:551~576.
[3] O’Connell R J , Budiansky B.Viscoelaslutic properties of fluid-saturated cracked solids[J].Geophys,Res.1977,82:5719~5735.
[4]尹军杰,刘学伟,李文慧.地震波散射理论及应用研究综述.地球物理学进展,2005,3,20(1): 123~134.
[5]王大兴,辛可锋,李幼铭等.地层条件下砂岩含水饱和度对波速及衰减影响的实验研究.地球物理学报,2006 ,49(3): 908～914
[6] Sothcott J , McCann C, O’Hara S G.. The influence of two different pore fluids on the acoustic properties of reservoir sandstones at sonic and ultrasonic frequencies. 70th Ann. Internat Mtg., Soc. Expi .Geophys. Expanded Abstracts , 2000.
[7] White J E, Boit G, 1986. Theory of extension waves in porousrods. Geophysics, 51 (3) : 742～745
[8] Klimentos T, Maccann C, 1990. Relationships among compressional wave attenuation, porosity, clay content, and per-meability in sandstones. Geophysics, 55 (8) : 998～1014
[9] Grant A G, 1994. Fluid effects on velocity and attenuation in sandstones. J Acoust Soc Amer, 96 (2) : 1 158～1173
[10]席道瑛,邱文亮,程经毅,易良坤,张斌,谢端.饱和多孔岩石的衰减与孔隙率和饱和度的关系.石油地球物理勘探,1997.32(2):196～201
[11]席道瑛,程经毅,张斌等.饱和多孔岩石应力波的衰减特性.地震学报,1997,19(5):457～461
[12]席道瑛.程经毅,席军.饱和砂岩滞弹性弛豫热激活过程机理探讨.石油地球物理勘探,1998,33(3):348一354
[13]席道瑛,刘斌,谢端,刘卫,易良坤,张斌.孔隙流体饱和砂岩的衰减与频率的相关性.石油地球物理勘探,1998,33(1):66-70,77
[14]席道瑛,刘斌,刘卫,易良坤.饱和多孔岩石弛豫衰减对时间和温度的依赖性.地球物理学报,2000,43(6):827～835
[15]席道瑛,刘爱文,刘卫.低频条件下饱和流体砂岩的衰减研究.地震学报,1995,17(4): 585～591
[16]席道瑛等.岩石中应力弛珠的衰减和模且色散.石油物探,1995.34(3)103~108
[17] Shatilo A.P., Sondergeld c.s., Ultrasonic attenuation in Glenn Pool Rocks, northeastern Oklahoma[J].Geophsics, 1998,63:465～478
[18] Jones T.D.,Pore fluids and frequency-dependent wave propagation in rocks[J]. Geophysics,1986,51:1935～1953
[19]席道瑛等.岩石中应力弛珠的衰减和模且色散[J].石油物探, 1995, 34(3): 103~108
[20]孙成禹,地震波动力学理论,石油大学研究生院教材。2003, 4:105~107
[21]胡昌华,张军波,夏军等.基于MATLAB的系统分析与设计——小波分析[M].西安:西安电子科技大学出版社. 2000,P3
[22]张贤达.现代信号处理[M].北京:清华大学出版社. 2002
[23] McFadden, P.D., Cook, J.G., and Forster, L.M., Decomposition of gear vibration signals by the generalized S-transform:Mech.Syst. Signal Process, 1999,13:691~707
[24] Stockwell R.G., MansinhaL, and Lowe R.P. Localization of the complex spectrum: the S transform [J]. IEEE Transactions on Signal Processing, 1996, Vol.44, No.4: 998~1001
[25]陈学华,贺振华.改进的S变换及在地震信号处理中的应用[J].数据采集与处理, 2005, 20(4): 449~453
[26]刘喜武,刘洪,李幼铭,年静波.基于广义S变换研究地震地层特征.球物理学进展, 2006, 21(2): 440~451
[27] Mansinha L, Stockwell R.G., Lowe R.P. Pattern Analysis with two dimensional spectral localization: Application of two dimensional S transform[J]. Physica A, 1997, 239: 286~295.
[28] Pinnegar C R, Mansinha L. The S-Transform With Windows of Arbitrary And Varying Shape[J]. Geophysics, 2003,68 (1): 381~385.
[29]陆基孟.地震勘探原理.东营:石油大学出版社, 1993.1:88~91
[30] Hemon C H , Mace D. Use of t he Karhunen-Loeve t ransformation in seismic data processing . Geophysical Prospecting ,1978 ,26 :600~626.
[31] Jones I.F., Levy S. Signal-to-noise ratio enhancement in multichannel seismic data via the Karhunen-Loeve transform .Geophysical Prospecting, 1987, 35: 12~32.
[32]付燕.人工地震信号去噪方法研究.西北工业大学博士论文,2002:77~79
[33]康冶,于承业,贾卧,王春梅.陈颖f-x域去噪方法研究.石油地球物理勘探,2003, 38(2): 136~138
[34]蔡加铭,周兴元,吴律.f-x域算子外推去噪技术研究[J].石油地球物理勘探,1999,34(3):325~331.
[35]国九英.叠前ω-x域算子外推法去噪[J].石油地球物理勘探,1995,30(4):487~494
[36]俞寿朋.地震信号的多项式拟合在偏移前资料处理中的应用[J].物探科技通报,1988, 6(1): 6~18.
[37]俞寿朋,蔡希铃.用地震信号多项式拟合提高叠加剖面信噪比[J].石油地球物理勘探, 1988,23(2):131～139.
[38]周怀来.基于小波变换的地震信号去噪方法研究与应用.成都理工大学硕士学位论文,2006
[39]邱庚香,熊彬,梁锦文.应用小波变换提高浅层地震记录分辨率[J].桂林工学院学报. 2003, 23(2): 159~164.
[40] Donoho D L. De_noising via soft-thresholding [J]. IEEE Trans on Information Theory , 1992 , 41 (3) : 613~627.
[41]李庆武,陈小刚.小波阈值去噪的一种改进方法.光学技术,2006,32(6):831~833.
[42] Bickel, S.H., and Natarajan, R.R., Plane-wave Q deconvolution[J]. Geophysics, 1985, 50: 1426~1439.
[43] Hargreaves,N.D., and Calvert, A.J. Inverse Q filtering by Fourier transform: Geophysics[J], 1991,56: 519~527
[44]裴江云,何樵登.基于Kjartansson模型的反Q滤波[J].地球物理学进展. 1994, 9(1):90~100
[45] Yanghua Wang. A stable and efficient approach of inverse Q filtering[J]. Geophysics, 2002, 67(2): 657~664
[46] Yanghua Wang. Inverse Q-filter for seismic resolution enhancement[J]. Geophysics, 2006 ,71(3):v51~v61
[47]白桦,李级鹏.基于时频分析的地层吸收补偿.石油地球物理勘探, 1999, 34(6):642~648
[48]李鲲鹏,李衍达,张学工。基于小波包分解的地层吸收补偿。地球物理学报,2000,43(4):542~549
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