软弱夹层对深水采油管柱地震反应的影响
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摘要
海底泥线以下分布的软弱夹层对深水采油管柱井身结构的稳定性有着重要影响,尤其当地震发生时,会在土层交界面处管柱截面产生很大的弯矩和剪力。依据桩基的动力响应理论,引入回传射线矩阵法,建立了适于深水采油管柱的地震响应分析模型。模型中将组合套管柱等效为变截面Timoshenko梁,分别从软弱夹层的厚度和剪切波速分析,探讨了套管柱在各土层交界面处弯矩和剪力幅值的变化规律。结果表明,当软弱夹层的剪切波速减小,或厚度趋向临界值hcr时,都会导致夹层界面处套管柱的弯矩和剪力幅值的增大。因此,海洋工程中在钻遇软弱夹层时须充分考虑其对套管柱地震反应的影响。
The soft interlayer under seafloor has great influence on the stability of subsea casing string for deepwater production.Especially,the earthquakes can cause a great bending moment and large shear force on the cross-section of casing string.An analytical model for the seismic response of subsea casing string is established on the basis of pile foundation theories and method of reverberation-ray matrix.The casing string is assumed to be a Timoshenko beam of variable cross-section.The bending moments and shear forces of different casing sections are discussed from the aspects of the shear wave velocity and thickness of soft interlayer.The result shows that while shear wave velocity of soft interlayer decreases or its thickness tends to the critical value hcr,the bending moment and shear force of casing string at interfaces of soft interlayer will increase accordingly.Therefore,influence of soft interlayer on seismic response of casing string should be fully taken into account in marine engineering.
The soft interlayer under seafloor has great influence on the stability of subsea casing string for deepwater production.Especially,the earthquakes can cause a great bending moment and large shear force on the cross-section of casing string.An analytical model for the seismic response of subsea casing string is established on the basis of pile foundation theories and method of reverberation-ray matrix.The casing string is assumed to be a Timoshenko beam of variable cross-section.The bending moments and shear forces of different casing sections are discussed from the aspects of the shear wave velocity and thickness of soft interlayer.The result shows that while shear wave velocity of soft interlayer decreases or its thickness tends to the critical value hcr,the bending moment and shear force of casing string at interfaces of soft interlayer will increase accordingly.Therefore,influence of soft interlayer on seismic response of casing string should be fully taken into account in marine engineering.
引文
[1]QUIROS G W,LITTLE R L.Deepwater soil propertiesand their impact on the geotechnical program[C]//Offshore Technology Conference.Houston:OffshoreTechnology,conference,2003.
[2]AKERS T J.Jetting of structural casing in deepwaterenvironments[C]//SPE Annual Technical Conference andExhibition.Sam Antonio:Society of Petroleum,Engineers,2006.
[3]徐荣强,陈建兵,刘正礼,等.喷射导管技术在深水钻井作业中的应用[J].石油钻探技术,2007,35(3):19-22.XU Rong-qiang,CHEN Jian-bing,LIU Zheng-li,et al.The application of jetting technology in deepwaterdrilling[J].Petroleum Drilling Techniques,2007,35(3):19-22.
[4]管志川,李春山,周广陈,等.深井和超深井钻井井身结构设计方法[J].石油大学学报(自然科学版),2001,25(6):42-44.GUAN Zhi-chuan,LI Chun-shan,ZHOU Guang-chen,et al.A method for designing casing program in deep andsuperdeep wells[J].Journal of China University ofPetroleum(Edition of Natural Science),2001,25(6):42-44.
[5]刘昭蜀,赵焕庭,范时清,等.南海地质[M].北京:科学出版社,2002.
[6]BORCHERDT R D.Effects of local geology on groundmotion near San Francisco Bay[J].Bulletin of theSeismological Society of America,1970,60(1):29-61.
[7]TABER J J,SMITH E G C.Frequency dependedamplification of weak ground motions in Porirua andLower Hutt,New Zealand[J].Bulletin of New ZealandNational Society for Earthquake Engineering,1992,25(4):303-331.
[8]HOWARD S M,PAO Y H.Analysis and experiments onstress waves in planar trusses[J].Jouranl of EngineeringMechanics,1998,124(8):884-891.
[9]PAO Y H,HOWARD S M,KEH D C.Dynamic responseand wave propagation in plane trusses and frames[J].AIAA Journal,1999,37(5):594-603.
[10]吴世明.土动力学[M].北京:中国建筑工业出版社,2000.
[11]苏堪华,管志川,苏义脑.深水钻井导管喷射下入深度确定方法[J].中国石油大学学报(自然科学版),2008,32(4):47-50.SU Kan-hua,GUAN Zhi-chuan,SU Yi-nao.Deter-mination method of conductor setting depth using jettingdrilling in deepwater[J].Journal of China University ofPetroleum(Edition of Natural Science),2008,32(4):47-50.
[12]TIMOSHENKO S P,GOODIER J N.Theory of elasticityThird Edition[M].New York:McGraw-Hill,1970.
[13]GAZETAS G,DOBRY R.Simple radiation dampingmodel for piles and footings[J].Journal of EngineeringMechanichs,ASCE,1984,110(6):937-956.
[14]BIRMAN V,BERT C W.On the choice of shearcorrection factor in sandwich structures[J].Journal ofSandwich Structures and Materials,2002,4(1):83-95.
[2]AKERS T J.Jetting of structural casing in deepwaterenvironments[C]//SPE Annual Technical Conference andExhibition.Sam Antonio:Society of Petroleum,Engineers,2006.
[3]徐荣强,陈建兵,刘正礼,等.喷射导管技术在深水钻井作业中的应用[J].石油钻探技术,2007,35(3):19-22.XU Rong-qiang,CHEN Jian-bing,LIU Zheng-li,et al.The application of jetting technology in deepwaterdrilling[J].Petroleum Drilling Techniques,2007,35(3):19-22.
[4]管志川,李春山,周广陈,等.深井和超深井钻井井身结构设计方法[J].石油大学学报(自然科学版),2001,25(6):42-44.GUAN Zhi-chuan,LI Chun-shan,ZHOU Guang-chen,et al.A method for designing casing program in deep andsuperdeep wells[J].Journal of China University ofPetroleum(Edition of Natural Science),2001,25(6):42-44.
[5]刘昭蜀,赵焕庭,范时清,等.南海地质[M].北京:科学出版社,2002.
[6]BORCHERDT R D.Effects of local geology on groundmotion near San Francisco Bay[J].Bulletin of theSeismological Society of America,1970,60(1):29-61.
[7]TABER J J,SMITH E G C.Frequency dependedamplification of weak ground motions in Porirua andLower Hutt,New Zealand[J].Bulletin of New ZealandNational Society for Earthquake Engineering,1992,25(4):303-331.
[8]HOWARD S M,PAO Y H.Analysis and experiments onstress waves in planar trusses[J].Jouranl of EngineeringMechanics,1998,124(8):884-891.
[9]PAO Y H,HOWARD S M,KEH D C.Dynamic responseand wave propagation in plane trusses and frames[J].AIAA Journal,1999,37(5):594-603.
[10]吴世明.土动力学[M].北京:中国建筑工业出版社,2000.
[11]苏堪华,管志川,苏义脑.深水钻井导管喷射下入深度确定方法[J].中国石油大学学报(自然科学版),2008,32(4):47-50.SU Kan-hua,GUAN Zhi-chuan,SU Yi-nao.Deter-mination method of conductor setting depth using jettingdrilling in deepwater[J].Journal of China University ofPetroleum(Edition of Natural Science),2008,32(4):47-50.
[12]TIMOSHENKO S P,GOODIER J N.Theory of elasticityThird Edition[M].New York:McGraw-Hill,1970.
[13]GAZETAS G,DOBRY R.Simple radiation dampingmodel for piles and footings[J].Journal of EngineeringMechanichs,ASCE,1984,110(6):937-956.
[14]BIRMAN V,BERT C W.On the choice of shearcorrection factor in sandwich structures[J].Journal ofSandwich Structures and Materials,2002,4(1):83-95.