页岩储层叠前密度稳定反演方法
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摘要
密度参数是页岩储层评价的重要敏感参数,但通常认为准确获得密度信息难度较大.本文探索提出了一种稳定的基于弹性阻抗的叠前密度反演方法,以提高优质页岩的识别精度.首先,基于不同的参数化弹性阻抗方程开展密度敏感性分析,优选了敏感性最高的Aki-Richards近似弹性阻抗方程作为反演方程.然后,在弹性阻抗方程线性化的基础上,假设反演方程系数矩阵的逆存在,将密度(取对数)表示为多个角度弹性阻抗(取对数)的加权和,通过井旁道弹性阻抗反演结果与测井数据的回归求取加权系数,避免了常规反演方法对大型系数矩阵的求逆计算,从而提高了密度反演的稳定性,同时由于利用测井资料作为匹配目标,密度反演的精度也得到了提高.模型试算和涪陵页岩气田的实际资料应用实践均表明了该方法能够有效地提高密度反演的精度与稳定性.
Density is an important sensitive parameter in shale reservoir evaluation,but it is generally considered difficult to determine it accurately.This study proposes a robust pre-stack density inversion method based on elastic impedance to improve the accuracy of high-quality shale identification.Firstly,the density sensitivity of different parameterized elastic impedance equations are analyzed using a shale model,and the Aki-Richards approximate elastic impedance equation with the highest density sensitivity is chosen as the inversion equation.Then,the elastic impedance equation is linearized,and density parameter(logarithm)is expressed as a weighted sum of multiple angular elastic impedances(logarithm)assuming the inverse of the coefficient matrix exists.The weight coefficients are obtained by the regression of the inverted elastic impedance at wells location and density log data,which avoids calculating the inverse of the largescale coefficient matrix,hence the stability of the density inversion is improved.Meanwhile,density well log is utilized as the matching target,so the accuracy of density inversion is also enhanced.The model test and the application to the Fuling shale gas field show that the proposed method can effectively improve the accuracy and stability of density inversion.
Density is an important sensitive parameter in shale reservoir evaluation,but it is generally considered difficult to determine it accurately.This study proposes a robust pre-stack density inversion method based on elastic impedance to improve the accuracy of high-quality shale identification.Firstly,the density sensitivity of different parameterized elastic impedance equations are analyzed using a shale model,and the Aki-Richards approximate elastic impedance equation with the highest density sensitivity is chosen as the inversion equation.Then,the elastic impedance equation is linearized,and density parameter(logarithm)is expressed as a weighted sum of multiple angular elastic impedances(logarithm)assuming the inverse of the coefficient matrix exists.The weight coefficients are obtained by the regression of the inverted elastic impedance at wells location and density log data,which avoids calculating the inverse of the largescale coefficient matrix,hence the stability of the density inversion is improved.Meanwhile,density well log is utilized as the matching target,so the accuracy of density inversion is also enhanced.The model test and the application to the Fuling shale gas field show that the proposed method can effectively improve the accuracy and stability of density inversion.
引文
Aki K,Richards P G.2002.Quantitative Seismology.2nd ed.Sausalito:University Science Books.
Aleardi M.2018.Estimating petrophysical reservoir properties through extended elastic impedance inversion:applications to off-shore and on-shore reflection seismic data.Journal of Geophysics and Engineering,15(5):2079-2090.
Alebouyeh M,Chehrazi A.2018.Application of extended elastic impedance(EEI)inversion to reservoir from non-reservoir discrimination of Ghar reservoir in one Iranian oil field within Persian Gulf.Journal of Geophysics and Engineering,15(4):1204-1213.
Alemie W,Sacchi M D.2011.High-resolution three-term AVOinversion by means of a trivariate cauchy probability distribution.Geophysics,76(3):R43-R55.
Alfred D,Vernik L.2013.A new petrophysical model for organic shales.Petrophysics,54(3):240-247.
Behura J,Kabir N,Crider R,et al.2010.Density extraction from P-wave AVO inversion:tuscaloosa trend example.The Leading Edge,29(7):772-777.
Buland A,Omre H.2003.Bayesian linearized AVO inversion.Geophysics,68(1):185-198.
Chen H Z,Yin X Y,Zhang J Q,et al.2014.Seismic inversion for fracture rock physics parameters using azimuthally anisotropic elastic impedance.Chinese Journal of Geophysics(in Chinese),57(10):3431-3441,doi:10.6038/cjg20141029.
Chen S,Zhao W Z,Ouyang Y L,et al.2017.Comprehensive prediction of shale gas sweet spots based on geophysical properties:A case study of the Lower Silurian Longmaxi Fm in Changning block,Sichuan Basin.Natrual Gas Industry(in Chinese),37(5):20-30.
Chen Z Q.2014.Quantitative seismic prediction technique of marine shale TOC and its application:A case from the Longmaxi Shale Play in the Jiaoshiba area,Sichuan Basin.Natural Gas Industry(in Chinese),34(6):24-29.
Connolly P.1999.Elastic impedance.The Leading Edge,18(4):438-452.
Downton J E.2005.Seismic parameter estimation from AVOinversion[Ph.D.thesis].Calgary:University of Calgary.
Fatti J L,Smith G C,Vail P J,et al.1994.Detection of gas in sandstone reservoirs using AVO analysis:A 3-D seismic case history using the Geostack technique.Geophysics,59(9):1362-1376.
Gidlow P M,Smith G C,Vail P.1992.Hydrocarbon detection using fluid factor traces,a case study:how useful is amplitudeversus-offset AVO analysis?.∥62nd Ann.Internat Mtg.,Soc.Expi.Geophys..Expanded Abstracts,78-89.
Gray D,Goodway B,Chen T.1999.Bridging the gap:using AVOto detect changes in fundamental elastic constants.∥69th Ann.Internat Mtg.,Soc.Expi.Geophys..Expanded Abstracts,852-855.
Kabir N,Lavaud B,Chavent G.2000.Estimation of the density contrast by AVO inversion beyond the linearized approximation:An indicator of gas saturation.∥70th Ann.Internat Mtg.,Soc.Expi.Geophys..Expanded Abstracts.
Kabir N,Crider R,Xia G Y,et al.2005.Can hydrocarbon saturation be estimated using density contrast parameter?.∥75th Ann.Internat Mtg.,Soc.Expi.Geophys..Expanded Abstracts.
Lim U Y,Gibson R L Jr,Kabir N,et al.2017.Inference of geomechanical properties of shales from AVO inversion based on the Zoeppritz equations.∥87th Ann.Internat Mtg.,Soc.Expi.Geophys..Expanded Abstracts,728-732.
Lines L.1999.Density and AVO.Canadian Journal of Exploration Geophysics,35(12):32-35.
Liu R B.2015.Typical features of the first giant shale gas field in China.Natural Gas Geoscience(in Chinese),26(8):1488-1498.
Liu X J,Yin X Y.2014.Direct estimation for fluid factor by two term AVO inversion for deep reservoir.∥84th Ann.Internat Mtg.,Soc.Expi.Geophys..Expanded Abstracts,574-579.
Liu X J,Yin X Y.2015.Blocky inversion with total variation regularization and bounds constraint.∥85th Ann.Internat Mtg.,Soc.Expi.Geophys..Expanded Abstracts,3497-3501.
Liu X J,Yin X Y,Wu G C,et al.2015.Prestack seismic inversion based on orthogonal matching pursuit algorithm.Oil Geophysical Prospecting(in Chinese),50(5):925-935.
Liu X J,Yin X Y,Wu G C,et al.2016.Identification of deep reservoir fluids based on basis pursuit inversion for elastic impedance.Chinese Journal of Geophysics(in Chinese),59(1):277-286,doi:10.6038/cjg20160123.
L?seth H,Wensaas L,Gading M,et al.2011.Can hydrocarbon source rocks be identified on seismic data?Geology,39(12):1167-1170.
Schmoker J S.1979.Determination of organic content of Appalachian Devonian shales from formation density log.AAPG Bulletin,63(9):1504-1537.
Sharma R K,Chopra S.2015.Estimation of density from seismic data without long offsets-a novel approach.∥85th Ann.Internat Mtg.,Soc.Expi.Geophys..Expanded Abstracts,2708-2110.
Shu M C,Wang Y F.2015.The posterior constrained regularization method for reservoir density inversion.Chinese Journal of Geophysics(in Chinese),58(6):2079-2086,doi:10.6038/cjg20150622.
Shuey R T.1985.A simplification of the Zoeppritz equations.Geophysics,50(4):609-614.
Wang B L,Yin X Y,Zhang F C.2006.Laméparameters inversion based on elastic impedance and its application.Applied Geophysics,3(3):174-178.
Wang B L,Yin X Y,Zhang F C.2007.Gray approximation-based elastic wave impedance equation and inversion.Oil Geophysical Prospecting(in Chinese),42(4):435-439.
Wang B L,Yin X Y,Zhang F C,et al.2008.Elastic impedance equation based on Fatti approximation and inversion.Progress in Geophysics(in Chinese),23(1):192-197.
Whitcombe D N.2002.Elastic impedance normalization.Geophysics,67(1):60-62.
Whitcombe D N,Connolly P A,Reagan R L,et al.2002.Extended elastic impedance for fluid and lithology prediction.Geophysics,67(1):63-67.
Yin X Y,Zhang S X,Zhang F C,et al.2010.Utilizing Russell approximation-based elastic wave impedance inversion to conduct reservoir description and fluid identification.OilGeophysical Prospecting(in Chinese),45(3):373-380.
Yin X Y,Cui W,Zong Z Y,et al.2014.Petrophysical property inversion of reservoirs based on elastic impedance.Chinese Journal of Geophysics(in Chinese),57(12):4132-4140,doi:10.6038/cjg20141224.
Yin X Y,Zhang S X.2014.Bayesian inversion for effective porefluid bulk modulus based on fluid-matrix decoupled amplitude variation with offset approximation.Geophysics,79(5):R221-R232.
Yin X Y,Liu X J,Wu G C,et al.2016.Basis pursuit inversion method under model constraint.GeophysicalProspectingfor Petroleum(in Chinese),55(1):115-122.
Zoeppritz K.1919.Erdbebenwellen VIII B,Uber Reflexion and Durchgang seismischer wellen durch Unstetigkeisflachen.Gottinger Nachr,17(1):66-84.
Zong Z Y,Yin X Y,Wu G C.2012.AVO inversion and poroelasticity with P-and S-wave moduli.Geophysics,77(6):N17-N24.
Zong Z Y,Yin X Y,Zhang F,et al.2012.Reflection coefficient equation and pre-stack seismic inversion with Young′s modulus and Poisson ratio.Chinese Journal of Geophysics(in Chinese),55(11):3786-3794,doi:10.6038/j.issn.0001-5733.2012.11.025.
Zong Z Y,Yin X Y,Wu G C.2013.Elastic impedance parameterization and inversion with Young′s modulus and Poisson′s ratio.Geophysics,78(6):N35-N42.
Zong Z Y,Yin X Y,Wu G C.2015.Geofluid discrimination incorporating poroelasticity and seismic reflection inversion.Surveys in Geophysics,36(5):659-681.
陈怀震,印兴耀,张金强等.2014.基于方位各向异性弹性阻抗的裂缝岩石物理参数反演方法研究.地球物理学报,57(10):3431-3441,doi:10.6038/cjg20141029.
陈胜,赵文智,欧阳永林等.2017.利用地球物理综合预测方法识别页岩气储层甜点——以四川盆地长宁区块下志留统龙马溪组为例.天然气工业,37(5):20-30.
陈祖庆.2014.海相页岩TOC地震定量预测技术及其应用——以四川盆地焦石坝地区为例.天然气工业,34(6):24-29.
刘若冰.2015.中国首个大型页岩气田典型特征.天然气地球科学,26(8):1488-1498.
刘晓晶,印兴耀,吴国忱等.2015.基于正交匹配追踪算法的叠前地震反演方法.石油地球物理勘探,50(5):925-935.
刘晓晶,印兴耀,吴国忱等.2016.基于基追踪弹性阻抗反演的深部储层流体识别方法.地球物理学报,59(1):277-286,doi:10.6038/cjg20160123.
舒梦珵,王彦飞.2015.储层重力密度反演后验约束正则化方法.地球物理学报,58(6):2079-2086,doi:10.6038/cjg20150622.
王保丽,印兴耀,张繁昌.2007.基于Gray近似的弹性波阻抗方程及反演.石油地球物理勘探,42(4):435-439.
王保丽,印兴耀,张繁昌等.2008.基于Fatti近似的弹性阻抗方程及反演.地球物理学进展,23(1):192-197.
印兴耀,张世鑫,张繁昌等.2010.利用基于Russell近似的弹性波阻抗反演进行储层描述和流体识别.石油地球物理勘探,45(3):373-380.
印兴耀,崔维,宗兆云等.2014.基于弹性阻抗的储层物性参数预测方法.地球物理学报,57(12):4132-4140,doi:10.6038/cjg20141224.
印兴耀,刘晓晶,吴国忱等.2016.模型约束基追踪反演方法.石油物探,55(1):115-122.
宗兆云,印兴耀,张峰等.2012.杨氏模量和泊松比反射系数近似方程及叠前地震反演.地球物理学报,55(11):3786-3794,doi:10.6038/j.issn.0001-5733.2012.11.025.
Aleardi M.2018.Estimating petrophysical reservoir properties through extended elastic impedance inversion:applications to off-shore and on-shore reflection seismic data.Journal of Geophysics and Engineering,15(5):2079-2090.
Alebouyeh M,Chehrazi A.2018.Application of extended elastic impedance(EEI)inversion to reservoir from non-reservoir discrimination of Ghar reservoir in one Iranian oil field within Persian Gulf.Journal of Geophysics and Engineering,15(4):1204-1213.
Alemie W,Sacchi M D.2011.High-resolution three-term AVOinversion by means of a trivariate cauchy probability distribution.Geophysics,76(3):R43-R55.
Alfred D,Vernik L.2013.A new petrophysical model for organic shales.Petrophysics,54(3):240-247.
Behura J,Kabir N,Crider R,et al.2010.Density extraction from P-wave AVO inversion:tuscaloosa trend example.The Leading Edge,29(7):772-777.
Buland A,Omre H.2003.Bayesian linearized AVO inversion.Geophysics,68(1):185-198.
Chen H Z,Yin X Y,Zhang J Q,et al.2014.Seismic inversion for fracture rock physics parameters using azimuthally anisotropic elastic impedance.Chinese Journal of Geophysics(in Chinese),57(10):3431-3441,doi:10.6038/cjg20141029.
Chen S,Zhao W Z,Ouyang Y L,et al.2017.Comprehensive prediction of shale gas sweet spots based on geophysical properties:A case study of the Lower Silurian Longmaxi Fm in Changning block,Sichuan Basin.Natrual Gas Industry(in Chinese),37(5):20-30.
Chen Z Q.2014.Quantitative seismic prediction technique of marine shale TOC and its application:A case from the Longmaxi Shale Play in the Jiaoshiba area,Sichuan Basin.Natural Gas Industry(in Chinese),34(6):24-29.
Connolly P.1999.Elastic impedance.The Leading Edge,18(4):438-452.
Downton J E.2005.Seismic parameter estimation from AVOinversion[Ph.D.thesis].Calgary:University of Calgary.
Fatti J L,Smith G C,Vail P J,et al.1994.Detection of gas in sandstone reservoirs using AVO analysis:A 3-D seismic case history using the Geostack technique.Geophysics,59(9):1362-1376.
Gidlow P M,Smith G C,Vail P.1992.Hydrocarbon detection using fluid factor traces,a case study:how useful is amplitudeversus-offset AVO analysis?.∥62nd Ann.Internat Mtg.,Soc.Expi.Geophys..Expanded Abstracts,78-89.
Gray D,Goodway B,Chen T.1999.Bridging the gap:using AVOto detect changes in fundamental elastic constants.∥69th Ann.Internat Mtg.,Soc.Expi.Geophys..Expanded Abstracts,852-855.
Kabir N,Lavaud B,Chavent G.2000.Estimation of the density contrast by AVO inversion beyond the linearized approximation:An indicator of gas saturation.∥70th Ann.Internat Mtg.,Soc.Expi.Geophys..Expanded Abstracts.
Kabir N,Crider R,Xia G Y,et al.2005.Can hydrocarbon saturation be estimated using density contrast parameter?.∥75th Ann.Internat Mtg.,Soc.Expi.Geophys..Expanded Abstracts.
Lim U Y,Gibson R L Jr,Kabir N,et al.2017.Inference of geomechanical properties of shales from AVO inversion based on the Zoeppritz equations.∥87th Ann.Internat Mtg.,Soc.Expi.Geophys..Expanded Abstracts,728-732.
Lines L.1999.Density and AVO.Canadian Journal of Exploration Geophysics,35(12):32-35.
Liu R B.2015.Typical features of the first giant shale gas field in China.Natural Gas Geoscience(in Chinese),26(8):1488-1498.
Liu X J,Yin X Y.2014.Direct estimation for fluid factor by two term AVO inversion for deep reservoir.∥84th Ann.Internat Mtg.,Soc.Expi.Geophys..Expanded Abstracts,574-579.
Liu X J,Yin X Y.2015.Blocky inversion with total variation regularization and bounds constraint.∥85th Ann.Internat Mtg.,Soc.Expi.Geophys..Expanded Abstracts,3497-3501.
Liu X J,Yin X Y,Wu G C,et al.2015.Prestack seismic inversion based on orthogonal matching pursuit algorithm.Oil Geophysical Prospecting(in Chinese),50(5):925-935.
Liu X J,Yin X Y,Wu G C,et al.2016.Identification of deep reservoir fluids based on basis pursuit inversion for elastic impedance.Chinese Journal of Geophysics(in Chinese),59(1):277-286,doi:10.6038/cjg20160123.
L?seth H,Wensaas L,Gading M,et al.2011.Can hydrocarbon source rocks be identified on seismic data?Geology,39(12):1167-1170.
Schmoker J S.1979.Determination of organic content of Appalachian Devonian shales from formation density log.AAPG Bulletin,63(9):1504-1537.
Sharma R K,Chopra S.2015.Estimation of density from seismic data without long offsets-a novel approach.∥85th Ann.Internat Mtg.,Soc.Expi.Geophys..Expanded Abstracts,2708-2110.
Shu M C,Wang Y F.2015.The posterior constrained regularization method for reservoir density inversion.Chinese Journal of Geophysics(in Chinese),58(6):2079-2086,doi:10.6038/cjg20150622.
Shuey R T.1985.A simplification of the Zoeppritz equations.Geophysics,50(4):609-614.
Wang B L,Yin X Y,Zhang F C.2006.Laméparameters inversion based on elastic impedance and its application.Applied Geophysics,3(3):174-178.
Wang B L,Yin X Y,Zhang F C.2007.Gray approximation-based elastic wave impedance equation and inversion.Oil Geophysical Prospecting(in Chinese),42(4):435-439.
Wang B L,Yin X Y,Zhang F C,et al.2008.Elastic impedance equation based on Fatti approximation and inversion.Progress in Geophysics(in Chinese),23(1):192-197.
Whitcombe D N.2002.Elastic impedance normalization.Geophysics,67(1):60-62.
Whitcombe D N,Connolly P A,Reagan R L,et al.2002.Extended elastic impedance for fluid and lithology prediction.Geophysics,67(1):63-67.
Yin X Y,Zhang S X,Zhang F C,et al.2010.Utilizing Russell approximation-based elastic wave impedance inversion to conduct reservoir description and fluid identification.OilGeophysical Prospecting(in Chinese),45(3):373-380.
Yin X Y,Cui W,Zong Z Y,et al.2014.Petrophysical property inversion of reservoirs based on elastic impedance.Chinese Journal of Geophysics(in Chinese),57(12):4132-4140,doi:10.6038/cjg20141224.
Yin X Y,Zhang S X.2014.Bayesian inversion for effective porefluid bulk modulus based on fluid-matrix decoupled amplitude variation with offset approximation.Geophysics,79(5):R221-R232.
Yin X Y,Liu X J,Wu G C,et al.2016.Basis pursuit inversion method under model constraint.GeophysicalProspectingfor Petroleum(in Chinese),55(1):115-122.
Zoeppritz K.1919.Erdbebenwellen VIII B,Uber Reflexion and Durchgang seismischer wellen durch Unstetigkeisflachen.Gottinger Nachr,17(1):66-84.
Zong Z Y,Yin X Y,Wu G C.2012.AVO inversion and poroelasticity with P-and S-wave moduli.Geophysics,77(6):N17-N24.
Zong Z Y,Yin X Y,Zhang F,et al.2012.Reflection coefficient equation and pre-stack seismic inversion with Young′s modulus and Poisson ratio.Chinese Journal of Geophysics(in Chinese),55(11):3786-3794,doi:10.6038/j.issn.0001-5733.2012.11.025.
Zong Z Y,Yin X Y,Wu G C.2013.Elastic impedance parameterization and inversion with Young′s modulus and Poisson′s ratio.Geophysics,78(6):N35-N42.
Zong Z Y,Yin X Y,Wu G C.2015.Geofluid discrimination incorporating poroelasticity and seismic reflection inversion.Surveys in Geophysics,36(5):659-681.
陈怀震,印兴耀,张金强等.2014.基于方位各向异性弹性阻抗的裂缝岩石物理参数反演方法研究.地球物理学报,57(10):3431-3441,doi:10.6038/cjg20141029.
陈胜,赵文智,欧阳永林等.2017.利用地球物理综合预测方法识别页岩气储层甜点——以四川盆地长宁区块下志留统龙马溪组为例.天然气工业,37(5):20-30.
陈祖庆.2014.海相页岩TOC地震定量预测技术及其应用——以四川盆地焦石坝地区为例.天然气工业,34(6):24-29.
刘若冰.2015.中国首个大型页岩气田典型特征.天然气地球科学,26(8):1488-1498.
刘晓晶,印兴耀,吴国忱等.2015.基于正交匹配追踪算法的叠前地震反演方法.石油地球物理勘探,50(5):925-935.
刘晓晶,印兴耀,吴国忱等.2016.基于基追踪弹性阻抗反演的深部储层流体识别方法.地球物理学报,59(1):277-286,doi:10.6038/cjg20160123.
舒梦珵,王彦飞.2015.储层重力密度反演后验约束正则化方法.地球物理学报,58(6):2079-2086,doi:10.6038/cjg20150622.
王保丽,印兴耀,张繁昌.2007.基于Gray近似的弹性波阻抗方程及反演.石油地球物理勘探,42(4):435-439.
王保丽,印兴耀,张繁昌等.2008.基于Fatti近似的弹性阻抗方程及反演.地球物理学进展,23(1):192-197.
印兴耀,张世鑫,张繁昌等.2010.利用基于Russell近似的弹性波阻抗反演进行储层描述和流体识别.石油地球物理勘探,45(3):373-380.
印兴耀,崔维,宗兆云等.2014.基于弹性阻抗的储层物性参数预测方法.地球物理学报,57(12):4132-4140,doi:10.6038/cjg20141224.
印兴耀,刘晓晶,吴国忱等.2016.模型约束基追踪反演方法.石油物探,55(1):115-122.
宗兆云,印兴耀,张峰等.2012.杨氏模量和泊松比反射系数近似方程及叠前地震反演.地球物理学报,55(11):3786-3794,doi:10.6038/j.issn.0001-5733.2012.11.025.