三角剪切断层传播褶皱应变分布
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摘要
三角剪切断层传播褶皱是褶皱-冲断带重要的构造样式和圈闭类型,通过研究构造变形几何特征与应变分布规律可探讨其成因机制。采用修正的满足速度连续性和应变相容性的三角剪切带速度分布模型,使用柯西方程计算三角剪切带内瞬时应变速率,分析其应变差异分布;使用MATLAB软件对三角剪切断层传播褶皱进行正演模拟,获得不同参数影响下褶皱的几何形态与累积应变分布特点,根据应变分布特征探讨可能的断层传播模式。结果表明:三角剪切带在断层端点前方区域存在应变集中,断层端点邻近区域变形强烈,将导致断层端点向前传播,应变随远离断层端点迅速衰减,岩层以褶皱形式协调变形;影响三角剪切断层传播褶皱应变分布的参数为三角剪切角与P/S比值。三角剪切角决定了褶皱宽度,剪切角越小,褶皱愈紧闭,应变也愈强烈;P/S比值影响着卷入变形的地层范围与累计应变的时间。高P/S比值时,断层迅速传播,地层变形微弱;低P/S比值时,地层累计变形时间长,变形强烈,断层下盘向斜构造明显发育,出现地层增厚的现象。
The tri-shear fault propagation fold is an important type of structural pattern and trap of fold-thrust belts. Its genetic mechanism can be explored by studying the characteristics of structural deformation geometry and strain distribution patterns. Based on improved tri-shear velocity distribution model which meets the requirements of divergence-free velocity field and strain compatibility,the instantaneous strain rate within the tri-shear zone was worked out,and in turn its strain difference distribution was analyzed. The forward modeling of the tri-shear fault propagation folds was performed with MATLAB software to obtain the geometry and cumulative strain distribution of folds under the influence of various parameters. Subsequently,the possible fault propagation modes were discussed according to the strain distribution. The results show that( 1) the predicted strain concentrates directly in the region near the fault tip and serious deformation occurs in the adjacent areas of the fault tip,causing the forward propagation of the tip,so the strain attenuates sharply with increasing distance from the tip,and rocks fold accordingly;( 2) The parameters affecting the strain distribution of tri-shear fault propagation folds are the apical angle of the tri-shear model and the ratio of P/S. The width of the fault propagation fold is directly controlled by the apical angle: with the decrease of the apical angle,the deformation zone becomes tighter and the strain grows stronger; while the P/S ratio affects the extent of strata involved in deformation and the cumulative strain time. When the ratio is high,the fault propagates fast and there is no significant internal deformation within the tri-shear zone,but when the ratio is low,beds have sufficient time to accumulate strain and deform before being cut by fault and result in pronounced synclines on the downthrown side of the fault and bed thickening.
The tri-shear fault propagation fold is an important type of structural pattern and trap of fold-thrust belts. Its genetic mechanism can be explored by studying the characteristics of structural deformation geometry and strain distribution patterns. Based on improved tri-shear velocity distribution model which meets the requirements of divergence-free velocity field and strain compatibility,the instantaneous strain rate within the tri-shear zone was worked out,and in turn its strain difference distribution was analyzed. The forward modeling of the tri-shear fault propagation folds was performed with MATLAB software to obtain the geometry and cumulative strain distribution of folds under the influence of various parameters. Subsequently,the possible fault propagation modes were discussed according to the strain distribution. The results show that( 1) the predicted strain concentrates directly in the region near the fault tip and serious deformation occurs in the adjacent areas of the fault tip,causing the forward propagation of the tip,so the strain attenuates sharply with increasing distance from the tip,and rocks fold accordingly;( 2) The parameters affecting the strain distribution of tri-shear fault propagation folds are the apical angle of the tri-shear model and the ratio of P/S. The width of the fault propagation fold is directly controlled by the apical angle: with the decrease of the apical angle,the deformation zone becomes tighter and the strain grows stronger; while the P/S ratio affects the extent of strata involved in deformation and the cumulative strain time. When the ratio is high,the fault propagates fast and there is no significant internal deformation within the tri-shear zone,but when the ratio is low,beds have sufficient time to accumulate strain and deform before being cut by fault and result in pronounced synclines on the downthrown side of the fault and bed thickening.
引文
[1]Suppe J.Geometry and kinematics of fault-bend folding[J].American Journal of Science,1983,283(7):684-721.
[2]Suppe J,Medwedeff D A.Geometry and kinematics of fault-propagation folding[J].Eclogae Geologicae Helvetiae,1990,83(3):409-454.
[3]何登发,Suppe J,贾承造.断层相关褶皱理论与应用研究新进展[J].地学前缘,2005,12(4):353-364.He Dengfa,Suppe John,Jia Chengzao.New advances in theory and application of fault related folding[J].Earth Science Frontiers,2005,12(4):353-364.
[4]Brandenburg J P.Trishear for curved faults[J].Journal of Structural Geology,2013,53(8):80-94.
[5]Allmendinger R W.Inverse and forward numerical modeling of trishear fault-propagation folds[J].Tectonics,1998,17(4):640-656.
[6]Gallup W B.Geology of Turner Valley oil and gas field,Alberta,Canada[J].AAPG Bulletin,1951,35(4):797-821.
[7]Tippett C R,Jones P B,Frey F R.Strains developed in the hangingwalls of thrusts due to their slip/propagation rate:a dislocation model:discussion[J].Journal of Structural Geology,1985,7(6):755-758.
[8]唐泽尧,杨天泉.卧龙河气田地质特征[J].天然气勘探与开发,1994,16(2):1-12.Tang Zeyao,Yang Tianquan.Geological characteristics of Wolonghe gas field in Sichuan basin[J].Natural Gas Exploration and Development[J].1994,16(2):1-12
[9]唐泽尧.四川卧龙河气田地质图集[M].北京:石油工业出版社,1993:1-78.Tang Zeyao.Geologicatlas of Wolonghe gas field in Sichuan Basin[M].Beijing:Petroleum Industry,1993:1-78.
[10]胡安平,陈汉林,杨树峰,等.卧龙河气田天然气成因及成藏主要控制因素[J].石油学报,2008,29(5):643-649.Hu Anping,Chen Hanlin,Yang Shufeng,et al.Origin of natural gas and main controlling factors of reservoirs in Wolonghe Gas Field[J].Acta Petrolei Sinica,2008,29(5):643-649.
[11]农成吉,程邦荣,黎洪珍,等.运用多学科知识综合解释卧龙河构造断陡带[J].天然气工业,2000,20(6):80-82.Nong Chengji,Cheng Bangrong,Li Hongzhen,et al.Comprehensive interpretation of steep faulted zone of Wolonghe Structural by use of multiple disciplines knowledge[J].Natural Gas Industry,2000,20(6):80-82.
[12]赵从俊,张健,沈浩,等.川东卧龙河构造形成机制与裂缝分布规律的定量研究[J].天然气工业,1993,13(6):1-8.Zhao Congjun,Zhang Jian,Shen Hao,et al.Quantitative study on the mechanism of forming Wolonghe structure and fracture distributionlaw in East Sichuan[J].Natural Gas Industry,1993,13(6):1-8.
[13]Bump A P.Reactivation,trishear modeling,and folded basement in Laramide uplifts:Implications for the origins of intra-continental faults[J].GSA Today,2003,13(3):4-10.
[14]李一泉,贾东,罗良,等.川西盐井沟断层传播褶皱的三维构造建模与磁组构分析[J].地学前缘,2007,14(4):74-84.Li Yiquan,Jia Dong,Luo Liang,et al.Three dimension construction and magnetic fabrics analysis of the Yanjianggou fault-propagation fold in western Sichuan[J].Earth Science Frontiers,2007,14(4):74-84.
[15]贾东,李一泉,王毛毛,等.断层相关褶皱的三维构造几何学分析:以川西三维地震工区为例[J].岩石学报,2011,27(3):732-740.Jia Dong,Li Yiquan,Wang Maomao,et al.Three-dimensional structural geometry of fault-related folds:Examples from 3-D seismic explored blocks in the western Sichuan Province,China[J].Acta Petrologica Sinica,2011,27(3):732-740.
[16]Brandes C,Tanner D C.Fault-related folding:A review of kinematic models and their application[J].Earth-Science Reviews,2014,138:352-370.
[17]Li Y,Jia D,Plesch A,et al.3-D geomechanical restoration and paleomagnetic analysis of fault-related folds:An example from the Yanjinggou anticline,southern Sichuan Basin[J].Journal of Structural Geology,2013,54(5):199-214.
[18]Allmendinger R W,Zapata T R,Manceda R,et al.Trishear kinematic modeling of structures,with examples from the Neuquén Basin,Argentina[C]//Mc Clay K R.Thrust tectonics and hydrocarbon systems.Tulsa:AAPG Memoir,2004:356-371.
[19]Erslev E A.Trishear fault-propagation folding[J].Geology,1991,19(6):617-620.
[20]何登发,Suppe John.三角剪切断层传播褶皱作用理论与应用[J].地学前缘,2007,14(4):66-73.He Dengfa,Suppe John.Theory and application of tri-shear fault propagation folding[J].Earth Science Frontiers,2007,14(4):66-73.
[21]Hardy S,Ford M.Numerical modeling of trishear fault propagation folding[J].Tectonics,1997,16(5):841-854.
[22]Hardy S,Mc Clay K.Kinematic modelling of extensional fault-propagation folding[J].Journal of Structural Geology,1999,21(7):695-702.
[23]Jin G,Groshong R H.Trishear kinematic modeling of extensional fault-propagation folding[J].Journal of Structural Geology,2006,28(1):170-183.
[24]Sharp I R,Gawthorpe R L,Underhill J R,et al.Fault-propagation folding in extensional settings:Examples of structural style and synrift sedimentary response from the Suez rift,Sinai,Egypt[J].GSA Bulletin,2000,112(12):1877-1899.
[25]Zehnder A T,Allmendinger R W.Velocity field for the trishear model[J].Journal of Structural Geology,2000,22(8):1009-1014.
[26]Cristallini E O,Allmendinger R W.Pseudo 3-D modeling of trishear fault-propagation folding[J].Journal of Structural Geology,2001,23(12):1883-1899.
[27]Cristallini E O,Giambiagi L,Allmendinger R W.True three-dimensional trishear:A kinematic model for strike-slip and oblique-slip deformation[J].GSA Bulletin,2004,116(7-8):938-952.
[28]Cardozo N.Trishear in 3D.Algorithms,implementation,and limitations[J].Journal of Structural Geology,2008,30(3):327-340.
[29]Cristallini E O,Allmendinger R W.Backlimb trishear:A kinematic model for curved folds developed over angular fault bends[J].Journal of Structural Geology,2002,24(2):289-295.
[30]Hardy S,Connors C D.Short note:A velocity description of shear fault-bend folding[J].Journal of Structural Geology,2006,28(3):536-543.
[31]Ziesch J,Tanner D C,Krawczyk C M.Strain associated with the faultparallel flow algorithm during kinematic fault displacement[J].Mathematical Geosciences,2014,46(1):59-73.
[32]Bump A P,Davis G H.Late Cretaceous-early Tertiary Laramide deformation of the northern Colorado Plateau,Utah and Colorado[J].Journal of Structural Geology,2003,25(3):421-440.
[33]Williams G,Chapman T.Strains developed in the hangingwalls of thrusts due to their slip/propagation rate:A dislocation model[J].Journal of Structural Geology,1983,5(6):563-571.
[34]孙健,罗兵.四川盆地涪陵页岩气田构造变形特征及对含气性的影响[J].石油与天然气地质,2016,37(6):809-819.Sun Jian,Luo Bing.Structural deformation and its influences on gas storage in Fuling shale gas play,the Sichuan Basin[J].Oil&Gas Geology,2016,37(6):809-819.
[35]Liu C,Yin H,Zhu L.Trishear Creator:A tool for the kinematic simulation and strain analysis of trishear fault-propagation folding with growth strata[J].Computers&Geosciences,2012,49(4):200-206.
[36]Johnson K M,Johnson A M.Mechanical models of trishear-like folds[J].Journal of Structural Geology,2002,24(2):277-287.
[37]刘中春,吕心瑞,李玉坤,等.断层对地应力场方向的影响机理[J].石油与天然气地质,2016,37(2):387-393.Liu Zhongchun,Lyu Xinrui,Li Yukun,et al.Mechanism of faults acting on in-situ stress field direction[J].Oil&Gas Geology,2016,37(2):387-393.
[38]李世愚,和泰名,尹祥础,等.岩石断裂力学导论[M].合肥:中国科学技术大学出版社,2010:10-15Li Shiyu,He Taiming,Yin Xiangchu,et al.Introduction of rock fracture mechanics[M].Hefei:Press of University of Science and Technology of China,2010:10-15.
[39]阿特金森B K.岩石断裂力学[M].尹祥础,修济刚,译.北京:地震出版社,1992:116-120.Barry Kean Atkinson.Fracture mechanics of rock[M].Yin Xiangchu,Xiu Jigang,Translated.Beijing:Seismological Press,1992:116-120.
[40]Andrews D J.Dynamic plane-strain shear rupture with a slip-weakening friction law calculated by a boundary integral method[J].Bulletin of the Seismological Society of America,1985,75(1):1-21.
[41]Andrews D J.Rupture velocity of plane strain shear cracks[J].Journal of Geophysical Research,1976,81(32):5679-5687.
[2]Suppe J,Medwedeff D A.Geometry and kinematics of fault-propagation folding[J].Eclogae Geologicae Helvetiae,1990,83(3):409-454.
[3]何登发,Suppe J,贾承造.断层相关褶皱理论与应用研究新进展[J].地学前缘,2005,12(4):353-364.He Dengfa,Suppe John,Jia Chengzao.New advances in theory and application of fault related folding[J].Earth Science Frontiers,2005,12(4):353-364.
[4]Brandenburg J P.Trishear for curved faults[J].Journal of Structural Geology,2013,53(8):80-94.
[5]Allmendinger R W.Inverse and forward numerical modeling of trishear fault-propagation folds[J].Tectonics,1998,17(4):640-656.
[6]Gallup W B.Geology of Turner Valley oil and gas field,Alberta,Canada[J].AAPG Bulletin,1951,35(4):797-821.
[7]Tippett C R,Jones P B,Frey F R.Strains developed in the hangingwalls of thrusts due to their slip/propagation rate:a dislocation model:discussion[J].Journal of Structural Geology,1985,7(6):755-758.
[8]唐泽尧,杨天泉.卧龙河气田地质特征[J].天然气勘探与开发,1994,16(2):1-12.Tang Zeyao,Yang Tianquan.Geological characteristics of Wolonghe gas field in Sichuan basin[J].Natural Gas Exploration and Development[J].1994,16(2):1-12
[9]唐泽尧.四川卧龙河气田地质图集[M].北京:石油工业出版社,1993:1-78.Tang Zeyao.Geologicatlas of Wolonghe gas field in Sichuan Basin[M].Beijing:Petroleum Industry,1993:1-78.
[10]胡安平,陈汉林,杨树峰,等.卧龙河气田天然气成因及成藏主要控制因素[J].石油学报,2008,29(5):643-649.Hu Anping,Chen Hanlin,Yang Shufeng,et al.Origin of natural gas and main controlling factors of reservoirs in Wolonghe Gas Field[J].Acta Petrolei Sinica,2008,29(5):643-649.
[11]农成吉,程邦荣,黎洪珍,等.运用多学科知识综合解释卧龙河构造断陡带[J].天然气工业,2000,20(6):80-82.Nong Chengji,Cheng Bangrong,Li Hongzhen,et al.Comprehensive interpretation of steep faulted zone of Wolonghe Structural by use of multiple disciplines knowledge[J].Natural Gas Industry,2000,20(6):80-82.
[12]赵从俊,张健,沈浩,等.川东卧龙河构造形成机制与裂缝分布规律的定量研究[J].天然气工业,1993,13(6):1-8.Zhao Congjun,Zhang Jian,Shen Hao,et al.Quantitative study on the mechanism of forming Wolonghe structure and fracture distributionlaw in East Sichuan[J].Natural Gas Industry,1993,13(6):1-8.
[13]Bump A P.Reactivation,trishear modeling,and folded basement in Laramide uplifts:Implications for the origins of intra-continental faults[J].GSA Today,2003,13(3):4-10.
[14]李一泉,贾东,罗良,等.川西盐井沟断层传播褶皱的三维构造建模与磁组构分析[J].地学前缘,2007,14(4):74-84.Li Yiquan,Jia Dong,Luo Liang,et al.Three dimension construction and magnetic fabrics analysis of the Yanjianggou fault-propagation fold in western Sichuan[J].Earth Science Frontiers,2007,14(4):74-84.
[15]贾东,李一泉,王毛毛,等.断层相关褶皱的三维构造几何学分析:以川西三维地震工区为例[J].岩石学报,2011,27(3):732-740.Jia Dong,Li Yiquan,Wang Maomao,et al.Three-dimensional structural geometry of fault-related folds:Examples from 3-D seismic explored blocks in the western Sichuan Province,China[J].Acta Petrologica Sinica,2011,27(3):732-740.
[16]Brandes C,Tanner D C.Fault-related folding:A review of kinematic models and their application[J].Earth-Science Reviews,2014,138:352-370.
[17]Li Y,Jia D,Plesch A,et al.3-D geomechanical restoration and paleomagnetic analysis of fault-related folds:An example from the Yanjinggou anticline,southern Sichuan Basin[J].Journal of Structural Geology,2013,54(5):199-214.
[18]Allmendinger R W,Zapata T R,Manceda R,et al.Trishear kinematic modeling of structures,with examples from the Neuquén Basin,Argentina[C]//Mc Clay K R.Thrust tectonics and hydrocarbon systems.Tulsa:AAPG Memoir,2004:356-371.
[19]Erslev E A.Trishear fault-propagation folding[J].Geology,1991,19(6):617-620.
[20]何登发,Suppe John.三角剪切断层传播褶皱作用理论与应用[J].地学前缘,2007,14(4):66-73.He Dengfa,Suppe John.Theory and application of tri-shear fault propagation folding[J].Earth Science Frontiers,2007,14(4):66-73.
[21]Hardy S,Ford M.Numerical modeling of trishear fault propagation folding[J].Tectonics,1997,16(5):841-854.
[22]Hardy S,Mc Clay K.Kinematic modelling of extensional fault-propagation folding[J].Journal of Structural Geology,1999,21(7):695-702.
[23]Jin G,Groshong R H.Trishear kinematic modeling of extensional fault-propagation folding[J].Journal of Structural Geology,2006,28(1):170-183.
[24]Sharp I R,Gawthorpe R L,Underhill J R,et al.Fault-propagation folding in extensional settings:Examples of structural style and synrift sedimentary response from the Suez rift,Sinai,Egypt[J].GSA Bulletin,2000,112(12):1877-1899.
[25]Zehnder A T,Allmendinger R W.Velocity field for the trishear model[J].Journal of Structural Geology,2000,22(8):1009-1014.
[26]Cristallini E O,Allmendinger R W.Pseudo 3-D modeling of trishear fault-propagation folding[J].Journal of Structural Geology,2001,23(12):1883-1899.
[27]Cristallini E O,Giambiagi L,Allmendinger R W.True three-dimensional trishear:A kinematic model for strike-slip and oblique-slip deformation[J].GSA Bulletin,2004,116(7-8):938-952.
[28]Cardozo N.Trishear in 3D.Algorithms,implementation,and limitations[J].Journal of Structural Geology,2008,30(3):327-340.
[29]Cristallini E O,Allmendinger R W.Backlimb trishear:A kinematic model for curved folds developed over angular fault bends[J].Journal of Structural Geology,2002,24(2):289-295.
[30]Hardy S,Connors C D.Short note:A velocity description of shear fault-bend folding[J].Journal of Structural Geology,2006,28(3):536-543.
[31]Ziesch J,Tanner D C,Krawczyk C M.Strain associated with the faultparallel flow algorithm during kinematic fault displacement[J].Mathematical Geosciences,2014,46(1):59-73.
[32]Bump A P,Davis G H.Late Cretaceous-early Tertiary Laramide deformation of the northern Colorado Plateau,Utah and Colorado[J].Journal of Structural Geology,2003,25(3):421-440.
[33]Williams G,Chapman T.Strains developed in the hangingwalls of thrusts due to their slip/propagation rate:A dislocation model[J].Journal of Structural Geology,1983,5(6):563-571.
[34]孙健,罗兵.四川盆地涪陵页岩气田构造变形特征及对含气性的影响[J].石油与天然气地质,2016,37(6):809-819.Sun Jian,Luo Bing.Structural deformation and its influences on gas storage in Fuling shale gas play,the Sichuan Basin[J].Oil&Gas Geology,2016,37(6):809-819.
[35]Liu C,Yin H,Zhu L.Trishear Creator:A tool for the kinematic simulation and strain analysis of trishear fault-propagation folding with growth strata[J].Computers&Geosciences,2012,49(4):200-206.
[36]Johnson K M,Johnson A M.Mechanical models of trishear-like folds[J].Journal of Structural Geology,2002,24(2):277-287.
[37]刘中春,吕心瑞,李玉坤,等.断层对地应力场方向的影响机理[J].石油与天然气地质,2016,37(2):387-393.Liu Zhongchun,Lyu Xinrui,Li Yukun,et al.Mechanism of faults acting on in-situ stress field direction[J].Oil&Gas Geology,2016,37(2):387-393.
[38]李世愚,和泰名,尹祥础,等.岩石断裂力学导论[M].合肥:中国科学技术大学出版社,2010:10-15Li Shiyu,He Taiming,Yin Xiangchu,et al.Introduction of rock fracture mechanics[M].Hefei:Press of University of Science and Technology of China,2010:10-15.
[39]阿特金森B K.岩石断裂力学[M].尹祥础,修济刚,译.北京:地震出版社,1992:116-120.Barry Kean Atkinson.Fracture mechanics of rock[M].Yin Xiangchu,Xiu Jigang,Translated.Beijing:Seismological Press,1992:116-120.
[40]Andrews D J.Dynamic plane-strain shear rupture with a slip-weakening friction law calculated by a boundary integral method[J].Bulletin of the Seismological Society of America,1985,75(1):1-21.
[41]Andrews D J.Rupture velocity of plane strain shear cracks[J].Journal of Geophysical Research,1976,81(32):5679-5687.