基于流体替换技术的地震AVO属性气藏识别(英文)
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摘要
传统上,油藏地球物理工程师是基于测井数据进行流体替换,计算油藏饱和不同流体时的弹性参数,并通过地震正演模拟分析油藏饱和不同流体时的地震响应,从而进行油气藏识别研究。该研究方案为油藏研究提供了重要的弹性参数和地震响应信息,但这些信息仅限于井眼位置。对于实际油藏条件,地下储层参数都是随位置变化而变化的,如孔隙度、泥质含量和油藏厚度等,因此基于传统流体替换方案得到的流体变化地震响应信息对于油气藏识别具有很大的局限性。研究通过设定联系油藏弹性参数与孔隙度、矿物组分等参数的岩石物理模型,并基于三层地质模型,进行地震正演模拟与AVO属性计算。得到油藏孔隙度、泥质含量和储层厚度变化时地震AVO属性,并建立了饱和水储层和含气储层对应AVO属性(包括梯度与截距)之间的定量关系。建立的AVO属性之间的线性关系可以实现基于地震AVO属性直接进行流体替换。最后,应用建立的流体替换前后AVO属性之间线性方程,对模拟地震数据直接进行流体替换,并通过流体替换前后AVO属性交汇图分析实现了气藏识别。
Traditionally, fluid substitutions are often conducted on log data for calculating reservoir elastic properties with different pore fluids. Their corresponding seismic responses are computed by seismic forward modeling for direct gas reservoir identification. The workflow provides us with the information about reservoir and seismic but just at the well. For real reservoirs, the reservoir parameters such as porosity, clay content, and thickness vary with location. So the information from traditional fluid substitution just at the well is limited. By assuming a rock physics model linking the elastic properties to porosity and mineralogy, we conducted seismic forward modeling and AVO attributes computation on a three-layer earth model with varying porosity, clay content, and formation thickness. Then we analyzed the relations between AVO attributes at wet reservoirs and those at the same but gas reservoirs. We arrived at their linear relations within the assumption framework used in the forward modeling. Their linear relations make it possible to directly conduct fluid substitution on seismic AVO attributes. Finally, we applied these linear relations for fluid substitution on seismic data and identified gas reservoirs by the cross-plot between the AVO attributes from seismic data and those from seismic data after direct fluid substitution.
Traditionally, fluid substitutions are often conducted on log data for calculating reservoir elastic properties with different pore fluids. Their corresponding seismic responses are computed by seismic forward modeling for direct gas reservoir identification. The workflow provides us with the information about reservoir and seismic but just at the well. For real reservoirs, the reservoir parameters such as porosity, clay content, and thickness vary with location. So the information from traditional fluid substitution just at the well is limited. By assuming a rock physics model linking the elastic properties to porosity and mineralogy, we conducted seismic forward modeling and AVO attributes computation on a three-layer earth model with varying porosity, clay content, and formation thickness. Then we analyzed the relations between AVO attributes at wet reservoirs and those at the same but gas reservoirs. We arrived at their linear relations within the assumption framework used in the forward modeling. Their linear relations make it possible to directly conduct fluid substitution on seismic AVO attributes. Finally, we applied these linear relations for fluid substitution on seismic data and identified gas reservoirs by the cross-plot between the AVO attributes from seismic data and those from seismic data after direct fluid substitution.
引文
Avseth, P. R., Mukerji, T., and Mavko, G.., 2005,Quantitative seismic interpretation: Cambridge UniversityPress, New York, 80 – 120.
Avseth, P. R., Dvorkin, J., Mavko, G.., et al., 2000, Rock physics diagnostic of North Sea sands: Link betweenmicrostructure and seismic properties: GeophysicalResearch Letters, 27, 2761 – 2764.
Batzle, M., and Wang, Z., 1992, Seismic properties of porefluids: Geophysics, 57(11), 1396 – 1408.
Dvorkin, J., and Nur, A., 1996, Elasticity of high-porosity sandstones: Theory for two North Sea datasets:Geophysics, 61, 1363 – 1370.
Dvorkin, J., Walls, J., Uden, R., et al., 2004, Lithology substitution in fluvial sand: The Leading Edge, 23(2),108 – 112.
Gassmann, F., 1951, Elasticity of porous media: Uberdie elastizitat poroser medien: Vierteljahrsschrift derNaturforschenden Gesselschaft, 96, 1 – 23.
Hashin, Z., and Shtrikman, S., 1963, A variational approach to the elastic behavior of multiphase materials: JournalMechanics Physical Solids, 11, 127 – 140.
Hill, R., 1952, The elastic behavior of crystalline aggre gate:Progress Physical Society., London, A65, 349 – 354.
Hilterman, F. J., 2001, Seismic amplitude interpretation:Distinguished Instructor Short Course, Society ofExploration Geophysicists, Tulsa.
Mavko, G.., Mukerji, T., and Dvorkin, J., 2009, The rock physics handbook: Cambridge University Press, NewYork, 207 – 311.
Mindlin, R. D., 1949, Compliance of elastic bodies incontact: Journal of Applied Mechanics, 16, 259 – 268.
Ross, C., 2000, Effective AVO crossplot modeling: Atutorial: Geophysics, 65(3), 700 – 711.
Singleton, S., and Kierstead, R., 2009, Calibration of pre-stack simultaneous impedance inversion using rockphysics: 79th Ann. Internat. Mtg., Soc. Explor. Geophys.,Expanded Abstracts, 1815 – 1819.
Shuey, R. T., 1985, A simplification of the Zoeppritz equations: Geophysics, 50, 619 – 624.
Spikes, K., Dvorkin, J., and Schneider, M., 2008, Fromseismic traces to reservoir properties: Physics-driveninversion: The Leading Edge, 27, 456 – 461.
Su, Y., Tao, Y., Wang, T., et al, 2010, AVO attributes interpretation and identification of lithological traps byprestack elastic parameters inversion – A case study inK Block, South Turgay Basin: 80th Ann. Internat. Mtg.,Soc. Explor. Geophys., Expanded Abstracts, 439 – 444.
Zoeppritz, K., 1919, über erdbebenwellen VIIIB: G ttinger Nachrichten, 1, 66 – 84.
Zou, Y., and Bentley, L. R., 2003, Time-lapse well loganalysis, fluid substitution, and AVO: The Leading Edge,22(6), 550 – 566.
Avseth, P. R., Dvorkin, J., Mavko, G.., et al., 2000, Rock physics diagnostic of North Sea sands: Link betweenmicrostructure and seismic properties: GeophysicalResearch Letters, 27, 2761 – 2764.
Batzle, M., and Wang, Z., 1992, Seismic properties of porefluids: Geophysics, 57(11), 1396 – 1408.
Dvorkin, J., and Nur, A., 1996, Elasticity of high-porosity sandstones: Theory for two North Sea datasets:Geophysics, 61, 1363 – 1370.
Dvorkin, J., Walls, J., Uden, R., et al., 2004, Lithology substitution in fluvial sand: The Leading Edge, 23(2),108 – 112.
Gassmann, F., 1951, Elasticity of porous media: Uberdie elastizitat poroser medien: Vierteljahrsschrift derNaturforschenden Gesselschaft, 96, 1 – 23.
Hashin, Z., and Shtrikman, S., 1963, A variational approach to the elastic behavior of multiphase materials: JournalMechanics Physical Solids, 11, 127 – 140.
Hill, R., 1952, The elastic behavior of crystalline aggre gate:Progress Physical Society., London, A65, 349 – 354.
Hilterman, F. J., 2001, Seismic amplitude interpretation:Distinguished Instructor Short Course, Society ofExploration Geophysicists, Tulsa.
Mavko, G.., Mukerji, T., and Dvorkin, J., 2009, The rock physics handbook: Cambridge University Press, NewYork, 207 – 311.
Mindlin, R. D., 1949, Compliance of elastic bodies incontact: Journal of Applied Mechanics, 16, 259 – 268.
Ross, C., 2000, Effective AVO crossplot modeling: Atutorial: Geophysics, 65(3), 700 – 711.
Singleton, S., and Kierstead, R., 2009, Calibration of pre-stack simultaneous impedance inversion using rockphysics: 79th Ann. Internat. Mtg., Soc. Explor. Geophys.,Expanded Abstracts, 1815 – 1819.
Shuey, R. T., 1985, A simplification of the Zoeppritz equations: Geophysics, 50, 619 – 624.
Spikes, K., Dvorkin, J., and Schneider, M., 2008, Fromseismic traces to reservoir properties: Physics-driveninversion: The Leading Edge, 27, 456 – 461.
Su, Y., Tao, Y., Wang, T., et al, 2010, AVO attributes interpretation and identification of lithological traps byprestack elastic parameters inversion – A case study inK Block, South Turgay Basin: 80th Ann. Internat. Mtg.,Soc. Explor. Geophys., Expanded Abstracts, 439 – 444.
Zoeppritz, K., 1919, über erdbebenwellen VIIIB: G ttinger Nachrichten, 1, 66 – 84.
Zou, Y., and Bentley, L. R., 2003, Time-lapse well loganalysis, fluid substitution, and AVO: The Leading Edge,22(6), 550 – 566.
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