基于离散元数值模拟的构造变形机制分析方法——以准噶尔盆地南缘为例  

Analysis of structural deformation mechanism based on discrete element numerical simulation:a case study of the southern margin of the Junggar Basin

作　　者：于宝利[1,2] 刘可禹 郭泊洋 林煜 陈鹏 庞志超 YU Baoli;LIU Keyu;GUO Boyang;LIN Yu;CHEN Peng;PANG Zhichao(School of Geosciences,China University of Petroleum(East China),Qingdao,Shandong 266555,China;BGP Inc.,CNPC,Zhuozhou,Hebei 072751,China;Geophysical Research Institute,BGP Inc.,CNPC,Zhuozhou,Hebei 072751,China;Research Institute of Exploration and Development,PetroChina Xinjiang Oilfield Company,Karamay,Xinjiang 834000,China)

机构地区：[1]中国石油大学(华东)地球科学与技术学院,山东青岛266555 [2]东方地球物理公司,河北涿州072751 [3]东方地球物理公司研究院,河北涿州072751 [4]中国石油新疆油田公司勘探开发研究院,新疆克拉玛依834000

出　　处：《石油地球物理勘探》2024年第5期1080-1098,共19页Oil Geophysical Prospecting

摘　　要：受多期构造运动影响,准噶尔盆地南缘前陆冲断褶皱带具横向东西分段、南北分带,纵向构造叠置的变形特征。但该区构造变形机制及样式的不同认识在一定程度上制约了油气勘探的深入。为探究准南缘新生代以来构造变形机制及其变形过程,本文利用高精度地震、钻井和岩石力学等资料,根据实际地质条件,重点考虑滑脱层的数量、强度及厚度变化,结合滑脱层纵向组合、横向分布范围及同沉积作用、先存构造等因素,共设计了10组模型,并采用离散元数值模拟方法开展了对比实验。实验结果表明,滑脱层强度、厚度及其组合主要控制冲断褶皱带构造纵向叠置关系及构造样式,滑脱层分布及同沉积作用主要控制其横向变形范围,先存构造主要影响后期构造的继承性发育。在此基础上,分段开展了多因素组合模拟实验并与实际地震剖面进行对比,重构了准南缘构造变形过程,揭示了新生代以来其构造变形机制,即先存断裂、古凸起、三套不同性质滑脱层纵向叠置关系和同沉积作用共同控制了西段构造的形成与演化,“下强上弱”“下薄上厚”两套纵向叠置滑脱层控制了中段构造的形成与演化,先存断裂及单套较弱滑脱层控制了东段构造的形成与演化。该方法可为类似的复杂构造变形区提供参考。Influenced by multiple tectonic movements,the foreland thrust-fold belt at the southern margin of the Junggar Basin exhibits segmented east-west sections and north-south zones,with deformation characteristics overlaid by vertical tectonic superposition.However,differing understandings of the tectonic deformation mechanism and styles in this area have hindered the depth of oil and gas exploration.To study the tectonic deformation mechanism and process of this area since the Neogene,this study utilizes high-precision seismic,drilling,and rock mechanics data.Based on actual geological conditions,it focuses on the number,strength,and thickness variations of detachment layers,combining factors such as their vertical combinations,lateral distribution ranges,syn-sedimentary processes,and pre-existing structures.Consequently,ten sets of models are designed,and comparative experiments are conducted using discrete element numerical simulation.The experimental results indicate that the strength,thickness,and combination of detachment layers control the vertical superposition relationships and structural styles of the thrust-fold belt,while the distribution of detachment layers and syn-sedimentary processes control the lateral deformation range.Pre-existing structures affect the later-stage inherited structural development.On this basis,multi-factor combination simulation experiments are carried out in sections and compared with actual seismic profiles,reconstructing the deformation processes of the southern margin of the Junggar Basin and revealing the tectonic deformation mechanism since the Neogene.This mechanism involves pre-existing faults,ancient uplifts,the vertical superposition relationship of three sets of slip layers with different nature,and syn-sedimentary processes,which control the formation and evolution of the structures in the western segment.Two sets of vertical superimposed slip layers,which are strong and thin at the bottom as well as weak and thick at the top,control the formation and evolution of the s

关 键 词：准噶尔盆地南缘 前陆冲断褶皱带 离散元数值模拟 滑脱层 先存构造 同沉积作用 

分 类 号：P631[天文地球—地质矿产勘探]