基于物理-数值联合模拟的多期断裂形成机制及演化研究
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摘要
针对多期叠加构造体系形成机制研究中存在的问题,以南堡凹陷3号构造古近系中大量存在的"X"型断裂样式为例,应用构造体系复合理论、构造物理-数值联合模拟分析裂陷盆地深部先期构造对晚期断裂形成和演化控制作用以及叠加构造形成力学机理,建立空间展布几何模式。研究认为:两期断裂系统的叠加规律主要受控于先期断裂的力学强度、晚期应力强度、先期断裂走向与后期应力方向之间的关系;先期断裂可以影响局部应力场的分布以及地层的力学强度,进而影响后期发育断裂的分布,后期应力场既可以使早期断裂继续扩展,也可以导致地层发生破裂产生新的断裂;伸展背景下,当后期张应力与早期断裂夹角小于30°时,只沿先期断裂扩展而不产生新的断裂;以不整合面分割形成的空间地质力学结构层,受后期强烈作用时,容易发生"变形不协调"现象,垂向上断裂系统具有明显不连续性,产状发生改变。因此,多期叠加断裂系统的形成和发育直接受控于郯庐断裂古近纪以来地质力学性质的转变。
To solve problems in studying the formation mechanism of multi-phrase superimposed structures,this paper took X-pattern normal faults in Nanpu No.3 region as the example to investigate the controlling role of pre-existing structure in the depth of rift basin on the formation and evolution of later fault and to analyze the mechanism of superimposed structures by using tectonic superposition theory and physical and numerical simulation.A geometric model of space distribution was established.Through these studies,several laws were obtained as follows.First,superposition manners mainly depend on the mechanical strength of pre-existing faults,the tectonic stress intensity of the later fauts,and the relation between the pre-existing fault strike and the stress orientation of late period.Secondly,the pre-existing faults,which can influence local distribution of stress field and the mechanical strength of stratum,influence the distribution of later fault development.In other words,the later stress field not only causes the further propagation of pre-existing faults,but also the generation of new rupture in overlying strata.However,under extension setting,the later stress field results in the propagation along pre-existing faults only without,generating new faults when the inclined angle is less than 30°.Besides,under the influence of strong later force,it is easy for the spatial mechanical stratigraphic sequences resulted from the segregation of plane of unconformity to produce the non-coordination strain phenomenon and to cause discontinuous faults vertically with changed occurrence.Therefore,the formation and development of the superimposed fault system is directly controlled by the change of geo-mechanical properties of Tan-Lu fault since Paleogene.
To solve problems in studying the formation mechanism of multi-phrase superimposed structures,this paper took X-pattern normal faults in Nanpu No.3 region as the example to investigate the controlling role of pre-existing structure in the depth of rift basin on the formation and evolution of later fault and to analyze the mechanism of superimposed structures by using tectonic superposition theory and physical and numerical simulation.A geometric model of space distribution was established.Through these studies,several laws were obtained as follows.First,superposition manners mainly depend on the mechanical strength of pre-existing faults,the tectonic stress intensity of the later fauts,and the relation between the pre-existing fault strike and the stress orientation of late period.Secondly,the pre-existing faults,which can influence local distribution of stress field and the mechanical strength of stratum,influence the distribution of later fault development.In other words,the later stress field not only causes the further propagation of pre-existing faults,but also the generation of new rupture in overlying strata.However,under extension setting,the later stress field results in the propagation along pre-existing faults only without,generating new faults when the inclined angle is less than 30°.Besides,under the influence of strong later force,it is easy for the spatial mechanical stratigraphic sequences resulted from the segregation of plane of unconformity to produce the non-coordination strain phenomenon and to cause discontinuous faults vertically with changed occurrence.Therefore,the formation and development of the superimposed fault system is directly controlled by the change of geo-mechanical properties of Tan-Lu fault since Paleogene.
引文
[1]李四光.地质力学概论[M].北京:地质力学出版社,1999.
[2]周海民,董月霞,夏文臣,等.断陷盆地油气勘探理论与实践:以渤海湾盆地南堡凹陷为例[M].北京:中国石油大学出版社,2001.
[3]周天伟,周建勋.南堡凹陷晚新生代X型断层形成机制及其对油气运聚的控制[J].大地构造与成矿学,2008,32(1):20-27.ZHOU Tianwei,ZHOU Jianxun.Formation mechanism of X-pattern normal faults during late Cenozoic and their impact on hydrocarbon accumulation in the Nanpu sag of Bohai bay basin[J].Geotectonica Et Metallogenia,2008,32(1):20-27.
[4]童亨茂,聂金英,孟令箭,等.基底先存构造对裂陷盆地断层形成和演化的控制作用规律[J].地学前缘,2009,16(4):97-104.TONG Hengmao,NIE Jinying,MENG Lingjian,et al.The law of basement pre-existing fabric controlling fault formation and evolution in rift basin[J].Earth Science Frontiers,2009,16(4):97-104.
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[6]MORLEY C K,GABDI S,SEUSUTTHIYA K.Fault superimposition and linkage resulting from stress changes during rifting:Examples from 3Dseismic data,Phitsanulok basin,Thailand[J].Journal of Structural Geology,2007,29(4):646-663.
[7]BYERLEE J D.Friction of rocks[J].Pure and Application Geophysics,1978,116(4/5):615-626.
[8]蔡蕊,刘浩.南堡凹陷高柳断裂带构造变形特征与物理模拟研究[J].特种油气藏,2013,20(4):41-44.CAI Rui,LIU Hao.Tectonic deformation and physical simulation of the Gaoliu fracture belt in Nanpu sag[J].Special Oil and Gas Reservoirs,2013,20(4):41-44.
[9]雷宝华.生长断裂活动强度定量研究的主要方法评述[J].地球科学进展,2012,27(9):947-956.LEI Baohua.Review of methods with quantitative studies of activity intensity of the growth fault[J].Advances in Earth Science,2012,27(9):947-956.
[10]童亨茂,赵宝银,曹哲,等.渤海湾盆地南堡凹陷断裂系统成因的构造解析[J].地质学报,2013,87(11):1647-1661.TONG Hengmao,ZHAO Baoyin,CAO Zhe,et al.Structural analysis of faulting system origin in the Nanpu sag,Bohai bay basin[J].Acta Geologica Sinica,2013,87(11):1647-1661.
[11]邓俊国,王贤.南堡凹陷构造应力场演化史与油气聚集[J].保定学院学报,1999,12(2):75-80.DENG Junguo,WANG Xian.The evolution history on the tectonic stress field and the oil-gas accumulation[J].Journal of Baoding Teachers College,1999,12(2):72-77.
[12]魏忠文,熊保贤,葛云龙,等.南堡凹陷北部东营末期构造应力场与油气运移关系的探讨[J].现代地质,2000,14(4):435-439.WEI Zhongwen,XIONG Baoxian,GE Yunlong,et al.Relationship between structural stress field and hydrocarbon migration in the northern Nanpu depression at the Late stage of Dongying[J].Geoscience,2000,14(4):435-439.
[13]万天丰.古构造应力场[M].北京:地质出版社,1988.
[14]徐嘉炜,马国锋.郯庐断裂带研究十年的回顾[J].地质论评,1992,38(4):316-324.XU Jiawei,MA Guofeng.Review of ten years(1981—1991)of research on the Tancheng-Lujiang fault zone[J].Geological Review,1992,38(4):316-324.
[15]王小凤,李中坚,陈柏林,等.郯庐断裂带[M].北京:地质出版社,2000.
[16]张克鑫,漆家福.潍北盆地新生代构造演化及其与郯庐断裂带的关系[J].石油天然气学报(江汉石油学院学报),2005,27(6):817-820.ZHANG Kexin,QI Jiafu.Tectonic evolution of Weibei basin in Cenozoic and its relationship with Tanlu fault zone[J].Journal of Jianghan Petroleum Institute,2005,27(6):817-820.
[17]张慧.太平洋板块俯冲对中国东北地区深浅震影响机理的数值模拟研究[D].北京:中国地震局地震预测研究所,2012.
[18]朱光,徐嘉炜,孙世群,等.郯庐断裂带平移时代的同位素年龄证据[J].地质论评,1995,41(5):452-456.ZHU Guang,XU Jiawei,SUN Shiqun,et al.Isotopic age evidence for the timing of strike-slip movement of the Tan-Lu fault zone[J].Geological Review,1995,41(5):452-456.
[2]周海民,董月霞,夏文臣,等.断陷盆地油气勘探理论与实践:以渤海湾盆地南堡凹陷为例[M].北京:中国石油大学出版社,2001.
[3]周天伟,周建勋.南堡凹陷晚新生代X型断层形成机制及其对油气运聚的控制[J].大地构造与成矿学,2008,32(1):20-27.ZHOU Tianwei,ZHOU Jianxun.Formation mechanism of X-pattern normal faults during late Cenozoic and their impact on hydrocarbon accumulation in the Nanpu sag of Bohai bay basin[J].Geotectonica Et Metallogenia,2008,32(1):20-27.
[4]童亨茂,聂金英,孟令箭,等.基底先存构造对裂陷盆地断层形成和演化的控制作用规律[J].地学前缘,2009,16(4):97-104.TONG Hengmao,NIE Jinying,MENG Lingjian,et al.The law of basement pre-existing fabric controlling fault formation and evolution in rift basin[J].Earth Science Frontiers,2009,16(4):97-104.
[5]MORLEY C K.A tectonic model for the Tertiary evolution of strike-slip faults and rift basins in SE Asia[J].Tectonophysics,2002,347(4):189-215.
[6]MORLEY C K,GABDI S,SEUSUTTHIYA K.Fault superimposition and linkage resulting from stress changes during rifting:Examples from 3Dseismic data,Phitsanulok basin,Thailand[J].Journal of Structural Geology,2007,29(4):646-663.
[7]BYERLEE J D.Friction of rocks[J].Pure and Application Geophysics,1978,116(4/5):615-626.
[8]蔡蕊,刘浩.南堡凹陷高柳断裂带构造变形特征与物理模拟研究[J].特种油气藏,2013,20(4):41-44.CAI Rui,LIU Hao.Tectonic deformation and physical simulation of the Gaoliu fracture belt in Nanpu sag[J].Special Oil and Gas Reservoirs,2013,20(4):41-44.
[9]雷宝华.生长断裂活动强度定量研究的主要方法评述[J].地球科学进展,2012,27(9):947-956.LEI Baohua.Review of methods with quantitative studies of activity intensity of the growth fault[J].Advances in Earth Science,2012,27(9):947-956.
[10]童亨茂,赵宝银,曹哲,等.渤海湾盆地南堡凹陷断裂系统成因的构造解析[J].地质学报,2013,87(11):1647-1661.TONG Hengmao,ZHAO Baoyin,CAO Zhe,et al.Structural analysis of faulting system origin in the Nanpu sag,Bohai bay basin[J].Acta Geologica Sinica,2013,87(11):1647-1661.
[11]邓俊国,王贤.南堡凹陷构造应力场演化史与油气聚集[J].保定学院学报,1999,12(2):75-80.DENG Junguo,WANG Xian.The evolution history on the tectonic stress field and the oil-gas accumulation[J].Journal of Baoding Teachers College,1999,12(2):72-77.
[12]魏忠文,熊保贤,葛云龙,等.南堡凹陷北部东营末期构造应力场与油气运移关系的探讨[J].现代地质,2000,14(4):435-439.WEI Zhongwen,XIONG Baoxian,GE Yunlong,et al.Relationship between structural stress field and hydrocarbon migration in the northern Nanpu depression at the Late stage of Dongying[J].Geoscience,2000,14(4):435-439.
[13]万天丰.古构造应力场[M].北京:地质出版社,1988.
[14]徐嘉炜,马国锋.郯庐断裂带研究十年的回顾[J].地质论评,1992,38(4):316-324.XU Jiawei,MA Guofeng.Review of ten years(1981—1991)of research on the Tancheng-Lujiang fault zone[J].Geological Review,1992,38(4):316-324.
[15]王小凤,李中坚,陈柏林,等.郯庐断裂带[M].北京:地质出版社,2000.
[16]张克鑫,漆家福.潍北盆地新生代构造演化及其与郯庐断裂带的关系[J].石油天然气学报(江汉石油学院学报),2005,27(6):817-820.ZHANG Kexin,QI Jiafu.Tectonic evolution of Weibei basin in Cenozoic and its relationship with Tanlu fault zone[J].Journal of Jianghan Petroleum Institute,2005,27(6):817-820.
[17]张慧.太平洋板块俯冲对中国东北地区深浅震影响机理的数值模拟研究[D].北京:中国地震局地震预测研究所,2012.
[18]朱光,徐嘉炜,孙世群,等.郯庐断裂带平移时代的同位素年龄证据[J].地质论评,1995,41(5):452-456.ZHU Guang,XU Jiawei,SUN Shiqun,et al.Isotopic age evidence for the timing of strike-slip movement of the Tan-Lu fault zone[J].Geological Review,1995,41(5):452-456.