走滑断裂分段叠置区物理模拟及构造差异性解析——以塔里木盆地顺北1号断裂为例  

Analogue modeling and structural differences of stepovers of strike slip faults:A case from Shunbei-1 fault of Tarim Basin

作　　者：刘芋杰 吴孔友[1] 刘寅[1] 何瑞武[2] 杜彦男 刘军[3] 张冠杰 LIU Yujie;WU Kongyou;LIU Yin;HE Ruiwu;DU Yannan;LIU Jun;ZHANG Guanjie(School of Geosciences,China University of Petroleum(East China),Qingdao 266580,Shandong Province,China;Sinopec Shengli Oilfield Company,Dongying 257000,Shandong Province,China;Sinopec Northwest Oilfield Company,Urumqi 830011,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266580 [2]中国石化胜利油田分公司,山东东营257000 [3]中国石化西北油田分公司,新疆乌鲁木齐830011

出　　处：《浙江大学学报（理学版）》2022年第3期363-375,共13页Journal of Zhejiang University（Science Edition）

基　　金：中国科学院战略性先导科技专项A类(XDA14010301)。

摘　　要：走滑断裂分段叠置区通常包括拉分叠置区和挤压叠置区,其形成及演化与油气藏关系密切,其内部构造特征对油气运聚具有重要影响。塔里木盆地顺托果勒地区顺北1号断裂叠置区分段发育特征明显,油气勘探表明,拉分叠置区和挤压叠置区对油气运聚的控制能力有一定差异。在分析构造特征的基础上,对走滑断裂拉分叠置区和挤压叠置区开展了物理模拟实验研究,结果显示,拉分叠置区内发育有多组里德尔(R)剪切和压剪性(P)剪切,在叠置区内多组断裂组成一套平面范围较小、垂向断距较大的雁列地堑系统;挤压叠置区内仅发育一组R剪切、P剪切及单条共轭里德尔(R’)剪切,并在叠置区内形成平面范围较大、垂向断距较小的地垒。因此认为,基底断裂的几何形态、运动性质是控制叠置区发育类型的关键因素。叠置区内断裂发育的数量、规模均受控于总走滑量,并与之呈正相关。相较于挤压叠置区,拉分叠置区的断层数更多,分布更密且地层破碎变形程度更高。在构造特征及力学机制上,拉分叠置区均表现出更强的油气富集潜力。Stepovers in strike-slip fault zones are usually associated with both releasing bends and restraining bends,whose occurrence and evolution are closely related with the hydrocarbon accumulation.Specifically,the structural difference between these two structures could significantly influence hydrocarbon migration and accumulation.Exploration data of the Shunbei-1 fault in the Shuntuoguole area of the Tarim Basin reflect that hydrocarbons are more enriched in releasing bends than the restraining bends.Based on the studies of structural characteristics of the Shunbei-1Fault,we conducted the simulation experiments to investigate the internal characteristics of these stepovers.Our results suggest that multiple sets of Riedel(R)shears and P shears are developed in the releasing bends,constituting an echelon pattern fault system,which shows a small range of deformation in the plan view and a large vertical displacement at the stepover in the section view.In contrast,only one set of R shear,one set of P shear,and an individual set of R’shear are observed in the restraining bends,forming a horst with a large range of deformation in the plan view and a small vertical fault displacement at the stepover in the section view.In general,the geometry and kinematic characteristics of basement faults are believed to be the key factors that control the development of types of stepovers.Moreover,the strike-slip displacement is found to be positively correlated with the number and scale of faults at the stepover.Specifically,compared with restraining bends,the releasing bends are characterized by a larger number of faults with denser planar distributions as well as strong strata deformation,and they are more favorable for hydrocarbon enrichment because of their structural characteristics and mechanical mechanisms.

关 键 词：走滑断裂 拉分叠置区 挤压叠置区 构造物理模拟 顺托果勒低隆 

分 类 号：P542[天文地球—构造地质学]