应用局部频率属性检测天然气藏
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摘要
地震记录作为地震波传播的时间函数,记录了地震波经地层传播后的响应特征。对地震信号做希尔伯特变换得到复地震道记录,再计算得到瞬时振幅、瞬时相位和瞬时频率属性参数,此三瞬属性参数在油藏储层预测与描述中起重要作用。但瞬时频率属性受相移、噪声及其他因素影响,其可解释性差,很难反映储层含流体后引起的频率变化特征。本文在分析研究常规地震记录瞬时频率属性计算方法基础上,提出了局部频率属性计算法;将其应用于实际地震储层的含气性检测,并综合利用转换波数据进行交互解释,结果证实局部频率属性能反映储层流体的频变特征,具有更高信噪比及较强可解释性,适用于天然气藏的储层预测和流体定性解释。
As time function of seismic wave propagation in subsurface,seismic trace is the response characteristic of reflection signal from the layers.Complex seismic trace analysis method is based on the Hilbert transform of the seismic signal,from which instantaneous amplitude,instantaneous phase and instantaneous frequency can be calculated.Three instantaneous attribute parameters play an important role in reservoir prediction and characterization.However,the frequency-dependent characteristic induced by the existed hydrocarbon in reservoir porous medium couldn't be found in the instantaneous frequency attribute section.The main reason is the lower resolution and complicate interpretation resulted from the phase shift effect on the computing process.In this paper,the conventional instantaneous frequency calculation method is reviewed and a novel local attribute technique is introduced into the local frequency attribute calculating method.The application of real field seismic datasets for hydrocarbon detecting in gas reservoir area indicates that the local frequency attribute can show the frequency-dependent response with the fluid in reservoir with higher signal-to-noise ratio and interpretation ability.Moreover,the integrated interpretation combined with the converted-wave seismic attribute can improve the ability of reservoir prediction and qualitative fluid detecting.
As time function of seismic wave propagation in subsurface,seismic trace is the response characteristic of reflection signal from the layers.Complex seismic trace analysis method is based on the Hilbert transform of the seismic signal,from which instantaneous amplitude,instantaneous phase and instantaneous frequency can be calculated.Three instantaneous attribute parameters play an important role in reservoir prediction and characterization.However,the frequency-dependent characteristic induced by the existed hydrocarbon in reservoir porous medium couldn't be found in the instantaneous frequency attribute section.The main reason is the lower resolution and complicate interpretation resulted from the phase shift effect on the computing process.In this paper,the conventional instantaneous frequency calculation method is reviewed and a novel local attribute technique is introduced into the local frequency attribute calculating method.The application of real field seismic datasets for hydrocarbon detecting in gas reservoir area indicates that the local frequency attribute can show the frequency-dependent response with the fluid in reservoir with higher signal-to-noise ratio and interpretation ability.Moreover,the integrated interpretation combined with the converted-wave seismic attribute can improve the ability of reservoir prediction and qualitative fluid detecting.
引文
[1]Li X and Zhang Y.Seismic reservoir characterization:how can multicomponent data help?Journal of Geo-physics and Engineering,2009,8(2):123～141
[2]Batzle M L,Han D and Hofmann R.Fluid mobilityand frequency-dependent seismic velocity—Directmeasurements.Geophysics,2006,71(1):N1～N9
[3]Aki K and Richards P G.Quantitative Seismology:Theory and Methods.W H Freeman&Co,1980
[4]Gassmann F.ber die Elastizitt poroser Medien.Veirteljahrsschrift der Naturforschenden Gesell-schaft in Zürich,1951,96:1～23
[5]Biot M A.Theory of propagation of elastic waves in afluid-saturated porous solid:Ⅰ.Low-frequencyrange.Journal of the Acoustical Society of Ameri-ca,1956a,28(2):168～178
[6]Biot M A.Theory of propagation of elastic waves in afluid-saturated porous solid:Ⅱ.Higher-frequencyrange.Journal of the Acoustical Society of Ameri-ca,1956b,28(2):179～191
[7]Pride S R,Berryman J G and Harris J M.Seismic at-tenuation due to wave induced flow.Journal of Geo-physical Research,2004,109,B1,B01201
[8]Chapman M.Frequency dependent anisotropy due tomesoscale fractures in the presence of equant porosi-ty.Geophysical Prospecting,2003,51(5):369～379
[9]Chapman M,Liu E and Li X.The influence of abnor-mally high reservoir attenuation on the AVO signa-ture.The Leading Edge,2005,24(11):1120～1125
[10]Chapman M,Liu E and Li X.The influence of fluid-sen-sitive dispersion and attenuation on AVO analysis.Geo-physical Journal International,2006,167(1):89～105
[11]Gabor D.Theory of communication.Journal of In-stituta of Electriad Engineers,1946,93(3):429～457
[12]Taner M T,Koehler F and Sheriff R E.Complex seismictrace analysis.Geophysics,1979,44(6):1041～1063
[13]Li X Y and Crampin S.Complex component analysisof shear-wave splitting:theory.Geophysical JournalInternational,1991,107(3):597～604
[14]Fomel S.Local seismic attributes.Geophysics,2007,72(3):A29～A33
[2]Batzle M L,Han D and Hofmann R.Fluid mobilityand frequency-dependent seismic velocity—Directmeasurements.Geophysics,2006,71(1):N1～N9
[3]Aki K and Richards P G.Quantitative Seismology:Theory and Methods.W H Freeman&Co,1980
[4]Gassmann F.ber die Elastizitt poroser Medien.Veirteljahrsschrift der Naturforschenden Gesell-schaft in Zürich,1951,96:1～23
[5]Biot M A.Theory of propagation of elastic waves in afluid-saturated porous solid:Ⅰ.Low-frequencyrange.Journal of the Acoustical Society of Ameri-ca,1956a,28(2):168～178
[6]Biot M A.Theory of propagation of elastic waves in afluid-saturated porous solid:Ⅱ.Higher-frequencyrange.Journal of the Acoustical Society of Ameri-ca,1956b,28(2):179～191
[7]Pride S R,Berryman J G and Harris J M.Seismic at-tenuation due to wave induced flow.Journal of Geo-physical Research,2004,109,B1,B01201
[8]Chapman M.Frequency dependent anisotropy due tomesoscale fractures in the presence of equant porosi-ty.Geophysical Prospecting,2003,51(5):369～379
[9]Chapman M,Liu E and Li X.The influence of abnor-mally high reservoir attenuation on the AVO signa-ture.The Leading Edge,2005,24(11):1120～1125
[10]Chapman M,Liu E and Li X.The influence of fluid-sen-sitive dispersion and attenuation on AVO analysis.Geo-physical Journal International,2006,167(1):89～105
[11]Gabor D.Theory of communication.Journal of In-stituta of Electriad Engineers,1946,93(3):429～457
[12]Taner M T,Koehler F and Sheriff R E.Complex seismictrace analysis.Geophysics,1979,44(6):1041～1063
[13]Li X Y and Crampin S.Complex component analysisof shear-wave splitting:theory.Geophysical JournalInternational,1991,107(3):597～604
[14]Fomel S.Local seismic attributes.Geophysics,2007,72(3):A29～A33
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