Based on the theory of structural analysis,the characteristics and structural patterns of subtle faults are studied using 3D seismic data of the Bohai Sea to analyze the development process and origin of the subtle fa...Based on the theory of structural analysis,the characteristics and structural patterns of subtle faults are studied using 3D seismic data of the Bohai Sea to analyze the development process and origin of the subtle faults.A method of identifying subtle faults is proposed,forming a complete system for analyzing origins of subtle faults in the Bohai Sea.The complex strike-slip fault patterns under the strike-slip and extension stress background,diverse formation rocks,and strong neotectonic movement are the reasons for the development of subtle faults.According to the tectonic origin and development location,the subtle faults in Bohai Sea can be divided into 12 types in the three categories of strike slip dominant,extension dominant and strike slip and extension composite,and the different types of subtle faults occur in different regions of the Bohai Sea.Unreasonable variation of sedimentary stratum thickness,inherited distortion or even abrupt change of stratum occurrence,zonation of plane fault combination and the variation of oil-water system in the same structure with no-lithologic change are the important signs for identifying subtle faults in Bohai Sea.The subtle faults greatly enlarge the size of the structural trap groups,and areas with dense subtle faults are often active area of hydrocarbon migration and accumulation and favorable exploration zones,which have strong control on the hydrocarbon accumulation.The identification method for subtle faults has guided the exploration in the mature areas of Bohai Sea effectively,with a number of large and medium oil and gas fields discovered,such as Bozhong 29-6 and Penglai 20-2.展开更多
The Central Asian Orogenic Belt(CAOB),the Earth’s largest Phanerozoic accretionary orogenic belt,is located between the Siberian,Tarim and North China Cratons and the Kazakhstan composite continent(Fig.1a).It is ca.8...The Central Asian Orogenic Belt(CAOB),the Earth’s largest Phanerozoic accretionary orogenic belt,is located between the Siberian,Tarim and North China Cratons and the Kazakhstan composite continent(Fig.1a).It is ca.800 km wide and extends from the Ural Mountains in the west to the Pacific in the east(e.g.,Zonenshain et al.,1990;Mossakovsky et al.,1993;Jahn et al.,2000;Windley et al.,2007,Xiao et al.,2010;Safonova et al.,2011).In the past two decades,many studies have shown that the CAOB is composed of many terranes of different tectonic origins,and was formed by successive accretion of terranes,microcontinents,island arcs,seamounts,ophiolites,and accretionary prisms from the early Neoproterozoic to the late Palaeozoic(e.g.,Mossakovsky et al.,1994;Badarch et al.,2002;Xiao et al.,2003;Buslov et al.,2001;Kovalenko et al.,2004;Safonova,2009;Li,2006;Kröner et al.,2007,2014;Donskaya et al.,2013;Xu et al.,2013).展开更多
基金Supported by the China National Science and Technology Major Project(2016ZX05024-003)CNOOC Science and Technology Major Project(CNOOC-KJ135ZDXM36TJ08TJ)。
文摘Based on the theory of structural analysis,the characteristics and structural patterns of subtle faults are studied using 3D seismic data of the Bohai Sea to analyze the development process and origin of the subtle faults.A method of identifying subtle faults is proposed,forming a complete system for analyzing origins of subtle faults in the Bohai Sea.The complex strike-slip fault patterns under the strike-slip and extension stress background,diverse formation rocks,and strong neotectonic movement are the reasons for the development of subtle faults.According to the tectonic origin and development location,the subtle faults in Bohai Sea can be divided into 12 types in the three categories of strike slip dominant,extension dominant and strike slip and extension composite,and the different types of subtle faults occur in different regions of the Bohai Sea.Unreasonable variation of sedimentary stratum thickness,inherited distortion or even abrupt change of stratum occurrence,zonation of plane fault combination and the variation of oil-water system in the same structure with no-lithologic change are the important signs for identifying subtle faults in Bohai Sea.The subtle faults greatly enlarge the size of the structural trap groups,and areas with dense subtle faults are often active area of hydrocarbon migration and accumulation and favorable exploration zones,which have strong control on the hydrocarbon accumulation.The identification method for subtle faults has guided the exploration in the mature areas of Bohai Sea effectively,with a number of large and medium oil and gas fields discovered,such as Bozhong 29-6 and Penglai 20-2.
文摘The Central Asian Orogenic Belt(CAOB),the Earth’s largest Phanerozoic accretionary orogenic belt,is located between the Siberian,Tarim and North China Cratons and the Kazakhstan composite continent(Fig.1a).It is ca.800 km wide and extends from the Ural Mountains in the west to the Pacific in the east(e.g.,Zonenshain et al.,1990;Mossakovsky et al.,1993;Jahn et al.,2000;Windley et al.,2007,Xiao et al.,2010;Safonova et al.,2011).In the past two decades,many studies have shown that the CAOB is composed of many terranes of different tectonic origins,and was formed by successive accretion of terranes,microcontinents,island arcs,seamounts,ophiolites,and accretionary prisms from the early Neoproterozoic to the late Palaeozoic(e.g.,Mossakovsky et al.,1994;Badarch et al.,2002;Xiao et al.,2003;Buslov et al.,2001;Kovalenko et al.,2004;Safonova,2009;Li,2006;Kröner et al.,2007,2014;Donskaya et al.,2013;Xu et al.,2013).
