未固结含气砂岩储层低频地震响应特征研究
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摘要
针对浅层未固结砂岩储层,本文引入了White薄层状模型,并结合Biot孔隙弹性介质波动理论,对储层部分含气和完全含水两种情况下的低频地震反射特征进行了理论计算,并运用OASES波场数值模拟软件包对这两种情况进行了数值模拟分析。与完全含水情形相比,储层部分含气时由于气泡的存在,岩石孔隙内的流体相对岩石骨架运动增强,波的传播速度随着地震波频率的降低而减小,砂岩储层与上、下围岩阻抗之差变大,从而引起地震低频反射能量相对增强,表现为明显的低频速度频散和低频反射异常。实际地震资料的低频能量分析结果表明,当未固结砂岩储层阻抗低于上下围岩阻抗时,低频地震能量异常现象可以作为识别储层含气的重要标志。
Regarding the shallow unconsolidated sand reservoir,the White thin layered model was introduced in this paper,by integrating with porous elastic medium wave theory the theoretical calculation of low frequency seismic reflection characteristics for partially gas bearing reservoir condition and total water-bearing rock condition were conducted,and then OASES wavefield numerical simulation software package was used to conduct numerical simulation analysis for the two conditions.Compared with totally water-bearing condition,the fluid in the pores of the partial gas-bearing reservoir could flow faster due to existence of bubbles in the fluid,then the wave propagation velocity decreases with the seismic wave frequency lowing down,as a result the impedance difference between the reservoir and the surrounding rocks will increase,so the final seismic low frequency reflection energy was relatively increased with obvious low frequency velocity frequency dispersion and low frequency reflection anomaly.The low frequency energy analysis for the field seismic data show that when the impedance of the unconsolidated sand reservoir is lower than that of the surrounding rocks,the low frequency energy anomaly can be regarded as an important indicator to identify a gas-bearing reservoir.
Regarding the shallow unconsolidated sand reservoir,the White thin layered model was introduced in this paper,by integrating with porous elastic medium wave theory the theoretical calculation of low frequency seismic reflection characteristics for partially gas bearing reservoir condition and total water-bearing rock condition were conducted,and then OASES wavefield numerical simulation software package was used to conduct numerical simulation analysis for the two conditions.Compared with totally water-bearing condition,the fluid in the pores of the partial gas-bearing reservoir could flow faster due to existence of bubbles in the fluid,then the wave propagation velocity decreases with the seismic wave frequency lowing down,as a result the impedance difference between the reservoir and the surrounding rocks will increase,so the final seismic low frequency reflection energy was relatively increased with obvious low frequency velocity frequency dispersion and low frequency reflection anomaly.The low frequency energy analysis for the field seismic data show that when the impedance of the unconsolidated sand reservoir is lower than that of the surrounding rocks,the low frequency energy anomaly can be regarded as an important indicator to identify a gas-bearing reservoir.
引文
[1]Goloshubin G Mand Bakulin A V.Seismic reflectivi-ty of a thin porous fluid-saturated layer versus fre-quency.SEG Technical Program Expanded Ab-stracts,1998,17:976～980
[2]Goloshubin G Mand Korneev V A.Seismic low-fre-quency effects from fluid-saturated reservoir.SEG Technical Program Expanded Abstracts,2000,19:976～979
[3]Castagna J P,Sun S and Siegfried R W.Instantanous spectral analysis:Detection of low-frequency shadows associated with hydrocarbons.The Leading Edge,2003,22(2):120～127
[4]Korneev V A,Goloshubin G Mand Daley T Met al.Seismic low-frequency effects in monitoring of fluid-saturated reservoirs.Geophysics,2004,69(2):522～532
[5]Taner M T,Koehler F and Sheriff E.Complex seis-mic trace analysis.Geophysics,1979,44(6):1041～1063
[6]Vander K C M,Guest WS and Potters J H.The3D shear experiment over Natih field in Oman:The effect of fracture-filling fluids on shear propagation.Geophysical Prospecting,2001,49(2):179～197
[7]Chapman M,Liu E and Li X.The influence of fluid-sensitive dispersion and attenuation on AVOanalysis.Geophysical Journal International,2006,167(1):89～105
[8]陈学华,贺振华,黄德济等.时频域油气储层低频阴影检测.地球物理学报,2009,52(1):215～221
[9]Widess M B.How thin is a thin bed Geophysics,1973,38(6):1176～1180
[10]Biot MA.Theory of propagation of elastic waves in a fluid-saturated porous solid,Ⅰ:Low-frequency range.Journal ofthe Acoustical Society of America,1956,28(2):168～178
[11]Biot M A.Theory of propagation of elastic waves in a fluid-saturated porous solid,Ⅱ:Higher frequency range.Journal of the Acoustical Society of Ameri-ca,1956,28(2):179～191
[12]Biot M A.Mechanics of deformation and acoustic propagation in porous media.Journal of Applied Physics,1962,33(4):1482～1498
[13]White J E.Computed seismic speeds and attenuation in rocks with partial gas saturation.Geophysics,1975,40(2):224～232
[14]Dvorkin J,Mavko Gand Nur A.Squirt flowin fully saturated rocks.Geophysics,1995,60(1):97～107
[15]Pride S R and Berryman J G.Linear dynamics of double-porosity dual-permeability materials.Ⅰ.Gov-erning equations and acoustical attenuation.Physical Review E,2003,68(3,036603):1～10
[16]Pride S R and Berryman J G.Linear dynamics of double-porosity dual-permeability materials.Ⅱ.Flu-id transport equations.Physical Review E,2003,68(3,036604):1～10
[17]Carcione J Mand Picotti S.P-wave seismic attenuation by slow-wave diffusion:Effects of inhomogeneous rock properties.Geophysics,2006,71(3):1～8
[18]Picotti S,Carcione J Mand Rubino J G.P-wave seis-mic attenuation by slow-wave diffusion:Numerical ex-periments in partially saturated rocks.Geophysics,2007,72(4):11～21
[19]White J E,Mikhaylova N Gand Lyakhovitskiy F M.Low-frequency seismic waves in fluid saturated lay-ered rocks.Izvestija Academy of Sciences USSR,Physics of the Solid Earth,1975,11(2):654～659
[20]Dutta N C and OdéH.Attenuation and dispersion of compressional waves in fluid-filled porous rocks with partial gas saturation(White model)-PartⅠ:Biot theory.Geophysics,1979,44(11):1777～1788
[21]Dutta N C and OdéH.Attenuation and dispersion of compressional waves in fluid filled porous rocks with partial gas saturation(White model)-PartⅡ,Re-sults.Geophysics,1979,44(11):1789～1805
[22]Dutta N C and Seriff AJ.On White's model of atten-uation in rocks with partial saturation.Geophysics,1979,44(11):1806～1812
[23]Trapeznikova N A.Prognosis and interpretation of seismic wave dynamics.Nauka,Moscow,1985,115
[24]Mavko G T,Mukerji and Dvokin J.The Rock Phys-ics Handbook.Cambridge,1998,71
[25]Haitao R,Goloshubin G and Hilterman F J.Ampli-tude-versus-frequency variations inthinlylayered por-ous rocks.SEG Technical Program Expanded Ab-stracts,2008,27:1744～1746
[26]Schmidt Hand Tango G.Efficient global matrix ap-proach to the computation of synthetic seismograms.Geophysical Journal of the Royal Astronomy Socie-ty,1986,84(2):331～359
[27]Schmidt H.OASES Version3.1User Guide and Reference manual.Massachusetts Institute of Tech-nology.2004
[28]Morlet J,Arens Gand Fourgeau Eet al.Wave prop-agation and sampling theory-Part1:Complex signal and scattering in multi-layered media.Geophysics,1982,47(2):203～221
[2]Goloshubin G Mand Korneev V A.Seismic low-fre-quency effects from fluid-saturated reservoir.SEG Technical Program Expanded Abstracts,2000,19:976～979
[3]Castagna J P,Sun S and Siegfried R W.Instantanous spectral analysis:Detection of low-frequency shadows associated with hydrocarbons.The Leading Edge,2003,22(2):120～127
[4]Korneev V A,Goloshubin G Mand Daley T Met al.Seismic low-frequency effects in monitoring of fluid-saturated reservoirs.Geophysics,2004,69(2):522～532
[5]Taner M T,Koehler F and Sheriff E.Complex seis-mic trace analysis.Geophysics,1979,44(6):1041～1063
[6]Vander K C M,Guest WS and Potters J H.The3D shear experiment over Natih field in Oman:The effect of fracture-filling fluids on shear propagation.Geophysical Prospecting,2001,49(2):179～197
[7]Chapman M,Liu E and Li X.The influence of fluid-sensitive dispersion and attenuation on AVOanalysis.Geophysical Journal International,2006,167(1):89～105
[8]陈学华,贺振华,黄德济等.时频域油气储层低频阴影检测.地球物理学报,2009,52(1):215～221
[9]Widess M B.How thin is a thin bed Geophysics,1973,38(6):1176～1180
[10]Biot MA.Theory of propagation of elastic waves in a fluid-saturated porous solid,Ⅰ:Low-frequency range.Journal ofthe Acoustical Society of America,1956,28(2):168～178
[11]Biot M A.Theory of propagation of elastic waves in a fluid-saturated porous solid,Ⅱ:Higher frequency range.Journal of the Acoustical Society of Ameri-ca,1956,28(2):179～191
[12]Biot M A.Mechanics of deformation and acoustic propagation in porous media.Journal of Applied Physics,1962,33(4):1482～1498
[13]White J E.Computed seismic speeds and attenuation in rocks with partial gas saturation.Geophysics,1975,40(2):224～232
[14]Dvorkin J,Mavko Gand Nur A.Squirt flowin fully saturated rocks.Geophysics,1995,60(1):97～107
[15]Pride S R and Berryman J G.Linear dynamics of double-porosity dual-permeability materials.Ⅰ.Gov-erning equations and acoustical attenuation.Physical Review E,2003,68(3,036603):1～10
[16]Pride S R and Berryman J G.Linear dynamics of double-porosity dual-permeability materials.Ⅱ.Flu-id transport equations.Physical Review E,2003,68(3,036604):1～10
[17]Carcione J Mand Picotti S.P-wave seismic attenuation by slow-wave diffusion:Effects of inhomogeneous rock properties.Geophysics,2006,71(3):1～8
[18]Picotti S,Carcione J Mand Rubino J G.P-wave seis-mic attenuation by slow-wave diffusion:Numerical ex-periments in partially saturated rocks.Geophysics,2007,72(4):11～21
[19]White J E,Mikhaylova N Gand Lyakhovitskiy F M.Low-frequency seismic waves in fluid saturated lay-ered rocks.Izvestija Academy of Sciences USSR,Physics of the Solid Earth,1975,11(2):654～659
[20]Dutta N C and OdéH.Attenuation and dispersion of compressional waves in fluid-filled porous rocks with partial gas saturation(White model)-PartⅠ:Biot theory.Geophysics,1979,44(11):1777～1788
[21]Dutta N C and OdéH.Attenuation and dispersion of compressional waves in fluid filled porous rocks with partial gas saturation(White model)-PartⅡ,Re-sults.Geophysics,1979,44(11):1789～1805
[22]Dutta N C and Seriff AJ.On White's model of atten-uation in rocks with partial saturation.Geophysics,1979,44(11):1806～1812
[23]Trapeznikova N A.Prognosis and interpretation of seismic wave dynamics.Nauka,Moscow,1985,115
[24]Mavko G T,Mukerji and Dvokin J.The Rock Phys-ics Handbook.Cambridge,1998,71
[25]Haitao R,Goloshubin G and Hilterman F J.Ampli-tude-versus-frequency variations inthinlylayered por-ous rocks.SEG Technical Program Expanded Ab-stracts,2008,27:1744～1746
[26]Schmidt Hand Tango G.Efficient global matrix ap-proach to the computation of synthetic seismograms.Geophysical Journal of the Royal Astronomy Socie-ty,1986,84(2):331～359
[27]Schmidt H.OASES Version3.1User Guide and Reference manual.Massachusetts Institute of Tech-nology.2004
[28]Morlet J,Arens Gand Fourgeau Eet al.Wave prop-agation and sampling theory-Part1:Complex signal and scattering in multi-layered media.Geophysics,1982,47(2):203～221
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