利用频变地震反射系数识别含气储层
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摘要
地震波在孔隙介质中传播的渐进方程可用于在地震频带内计算法向入射反射系数,这个频变的反射系数可用一个无量纲的参数ε来表示,ε可表示为储层流动性参数(即粘滞性的倒数)、流体密度和信号频率的乘积。利用该表达式,对中国新场气田的实际数据进行了计算,新场气田的储层大多为超致密的砂岩并且渗透率很低。在计算结果上观测到了砂岩储层内过渡区的气水界面上反射系数在地震频带内随频率变化的现象。利用该研究结果指导了地震反演并提取了相应的地震属性,这些属性被首先用于进行的流体(气或水)辨别,最后,在此基础上进行了含气和含水储层的识别。
The asymptotic equation of wave propagation in fluid-saturated porous media is available for calculating the normal reflection coefficient within seismic frequency band.This frequency-dependent reflection coefficient is expressed in terms of a dimensionless parameter,which is the product of the reservoir fluid mobility(i.e.inverse viscosity),fluid density,and the frequency of the signal.In this paper,we apply this expression to Xinchang gas-field,China,where reservoirs are super in tight sands with very low permeability.We demonstrate that the variation in reflection coefficient at gas/water contacts is as a transition zone within a sand formation observable within seismic frequency band.Then we conduct seismic inversion to generate attributes which first indicate the existence of fluid(either gas or water),and then discriminate a gas reservoir from a water reservoir.
The asymptotic equation of wave propagation in fluid-saturated porous media is available for calculating the normal reflection coefficient within seismic frequency band.This frequency-dependent reflection coefficient is expressed in terms of a dimensionless parameter,which is the product of the reservoir fluid mobility(i.e.inverse viscosity),fluid density,and the frequency of the signal.In this paper,we apply this expression to Xinchang gas-field,China,where reservoirs are super in tight sands with very low permeability.We demonstrate that the variation in reflection coefficient at gas/water contacts is as a transition zone within a sand formation observable within seismic frequency band.Then we conduct seismic inversion to generate attributes which first indicate the existence of fluid(either gas or water),and then discriminate a gas reservoir from a water reservoir.
引文
[1]GurevichB,CizR,DennemanA IM.Simpleexpressionsfor normal incidence reflection coefficients from an interface between fluid-saturated porous materials[J].Geo-physics,2004,69:1372-1377.
[2]李勇,肖富森,马廷虎,等.双相介质中储层波场特征数值模拟研究[J].西南石油大学学报:自然科学版,2009,31(3):13-15.Li Yong,Xiao Fusen,Ma Tinghu,et al.Reservoir wavefield characteristic numerical simulation in two-phase me-dia[J].Journal of Southwest Petroleum University:Sci-ence&Technology Edition,2009,31(3):13-15.
[3]Dvorkin J,Nur A.Dynamic poroelasticity:A unifiedmodel with the squirt and the Biot mechanisms[J].Geo-physics,1993,58:524-533.
[4]Biot M A.Theory of propagation of elastic waves in afluid-saturated porous solid,I:low-frequency range[J].J.Acoust.Soc.Am.,1956,28:168-178.
[5]Biot M A.Theory of propagation of elastic waves in afluid-saturatedporoussolid,II:higherfrequencyrange[J].J.Acoust.Soc.Am.,1956,28:179-191.
[6]BarenblattGI,ZheltovIP,KochinaIN.Basicconceptsinthe theory of seepage of homogeneous liquids in fissuredrocks[J].J.Appl.Math.Mech.,1960,24:1286-303.
[7]Pride S R,Berryman J G.Linear dynamics of double-porosity dual-permeability materials,I:Governing equa-tions and acoustic attenuation[J].Phys.Rev.,2003,68:1-10.
[8]Pride S R,Berryman J G.Linear dynamics of double-porosity dual-permeability materials,II:Fluid transportequations[J].Phys.Rev.,2003,68:1-10.
[9]GoloshubinGM,KorneevVA,SilinDB,etal.Reservoirimaging using low frequencies of seismic reflections[J].The Leading Edge,2006,25:527-531.
[10]Goloshubin G,Silin D,Vingalov V,et al.Reservoir per-meability from seismic attribute analysis[J].The LeadingEdge,2008,27:376-381.
[11]Goloshubin G M,Silin D.B.Using frequency-dependentseismic attributes in imaging of a fractured reservoir[C].Expanded Abstracts,76thSEG Annual Meeting,New Or-leans,2006:1742-1746.
[12]Denneman A I M,Drijkoningen G G,Smeulders D MJ,et al.Reflection and transmission of waves at a flu-id/porous-medium interface[J].Geophysics,2002,67:282-291.
[13]Silin D B,Korneev V A,Goloshubin G M.et al.Low-frequencyasymptoticanalysisofseismicreflectionfromafluid-saturated medium[J].Transp.Porous Media,2006,62:283-305.
[14]Silin D B,Goloshubin G M.An asymptotic model of seis-mic reflection from a permeable layer[J].Transp.PorousMedia,2010,83:233-256.
[15]Gan Q,Xu D,Tang J,et al.Seismic resolution enhance-ment for tight-sand gas reservoir characterization[J].Journal of Geophysics and Engineering,2009,6:21-28.
[16]Biot M A.Mechanics of deformation and acoustic pro-pagation in porous media[J].Journal of Applied Physics,1962,33:1482-1498.
[17]Gassmann F.über die Elastizit t por ser Medien.Viertel-jahrsr[J].Nat.Ges.Zür.,1951,96:1-23.
[18]Xu Duo.Seismic normal reflection based on the asymp-totic equation in porous media[R].Postdoctoral ResearchReport,The Centre for Reservoir Geophysics,ImperialCollege London.
[19]Lorenz E.The Essence of Chaos[M].Seattle:Universityof Washington Press,1993.
[20]Chapman M.Frequency-dependent anisotropy due tomeso-scale fractures in the presence of equant porosity[J].Geophysical Prospecting,2003,51:369-379.
[21]Korneev V,Goloshubin G,Daley T,et al.Seismic low-frequency effects in monitoring fluid saturated reser-voirs[J].Geophysics,2004,69:522-532.
[2]李勇,肖富森,马廷虎,等.双相介质中储层波场特征数值模拟研究[J].西南石油大学学报:自然科学版,2009,31(3):13-15.Li Yong,Xiao Fusen,Ma Tinghu,et al.Reservoir wavefield characteristic numerical simulation in two-phase me-dia[J].Journal of Southwest Petroleum University:Sci-ence&Technology Edition,2009,31(3):13-15.
[3]Dvorkin J,Nur A.Dynamic poroelasticity:A unifiedmodel with the squirt and the Biot mechanisms[J].Geo-physics,1993,58:524-533.
[4]Biot M A.Theory of propagation of elastic waves in afluid-saturated porous solid,I:low-frequency range[J].J.Acoust.Soc.Am.,1956,28:168-178.
[5]Biot M A.Theory of propagation of elastic waves in afluid-saturatedporoussolid,II:higherfrequencyrange[J].J.Acoust.Soc.Am.,1956,28:179-191.
[6]BarenblattGI,ZheltovIP,KochinaIN.Basicconceptsinthe theory of seepage of homogeneous liquids in fissuredrocks[J].J.Appl.Math.Mech.,1960,24:1286-303.
[7]Pride S R,Berryman J G.Linear dynamics of double-porosity dual-permeability materials,I:Governing equa-tions and acoustic attenuation[J].Phys.Rev.,2003,68:1-10.
[8]Pride S R,Berryman J G.Linear dynamics of double-porosity dual-permeability materials,II:Fluid transportequations[J].Phys.Rev.,2003,68:1-10.
[9]GoloshubinGM,KorneevVA,SilinDB,etal.Reservoirimaging using low frequencies of seismic reflections[J].The Leading Edge,2006,25:527-531.
[10]Goloshubin G,Silin D,Vingalov V,et al.Reservoir per-meability from seismic attribute analysis[J].The LeadingEdge,2008,27:376-381.
[11]Goloshubin G M,Silin D.B.Using frequency-dependentseismic attributes in imaging of a fractured reservoir[C].Expanded Abstracts,76thSEG Annual Meeting,New Or-leans,2006:1742-1746.
[12]Denneman A I M,Drijkoningen G G,Smeulders D MJ,et al.Reflection and transmission of waves at a flu-id/porous-medium interface[J].Geophysics,2002,67:282-291.
[13]Silin D B,Korneev V A,Goloshubin G M.et al.Low-frequencyasymptoticanalysisofseismicreflectionfromafluid-saturated medium[J].Transp.Porous Media,2006,62:283-305.
[14]Silin D B,Goloshubin G M.An asymptotic model of seis-mic reflection from a permeable layer[J].Transp.PorousMedia,2010,83:233-256.
[15]Gan Q,Xu D,Tang J,et al.Seismic resolution enhance-ment for tight-sand gas reservoir characterization[J].Journal of Geophysics and Engineering,2009,6:21-28.
[16]Biot M A.Mechanics of deformation and acoustic pro-pagation in porous media[J].Journal of Applied Physics,1962,33:1482-1498.
[17]Gassmann F.über die Elastizit t por ser Medien.Viertel-jahrsr[J].Nat.Ges.Zür.,1951,96:1-23.
[18]Xu Duo.Seismic normal reflection based on the asymp-totic equation in porous media[R].Postdoctoral ResearchReport,The Centre for Reservoir Geophysics,ImperialCollege London.
[19]Lorenz E.The Essence of Chaos[M].Seattle:Universityof Washington Press,1993.
[20]Chapman M.Frequency-dependent anisotropy due tomeso-scale fractures in the presence of equant porosity[J].Geophysical Prospecting,2003,51:369-379.
[21]Korneev V,Goloshubin G,Daley T,et al.Seismic low-frequency effects in monitoring fluid saturated reser-voirs[J].Geophysics,2004,69:522-532.
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