鄂尔多斯盆地南部地区断裂构造与油气成藏关系再认识:以彬长地区为例  

Further Understanding of Relationship between Fault Characteristics and Hydrocarbon Accumulation in Binchang Area,Ordos Basin

作　　者：何发岐[1] 齐荣[1] 袁春艳[1] 杨飞[1] 黎小伟[1] He Faqi;Qi Rong;Yuan Chunyan;Yang Fei;Li Xiaowei(SINOPEC North China Oil and Gas Branch,Zhengzhou 450006,China)

机构地区：[1]中国石化华北油气分公司,河南郑州450006

出　　处：《地球科学》2024年第11期4082-4097,共16页Earth Science

基　　金：国家重大科技专项(No.2016ZX05048).

摘　　要：鄂尔多斯盆地南部断裂构造发育特征及其与油气成藏的关系是被关注了很久然而未得到充分理解的问题.一种观点认为是一个断裂构造不发育的地区,致使该区油气勘探以地层‒岩性油气藏为主.随着3D地震勘探展开,发现研究区发育大量的倾角大、垂直断距小、分期活动的走滑断裂.以鄂尔多斯盆地西南缘彬长地区断裂为研究对象,通过地震资料分析了断裂几何学和运动学特征,探讨了断裂构造与油气成藏关系.研究表明,纵向上研究区可划分为3个构造层:下构造层(Tg-T9)、中构造层(T9-T5)和上构造层(T5以上).3个构造层的断裂发育具有明显的差异性,同时也具有一定的相似性和继承性.下构造层主要受加里东‒海西运动影响,中构造层主要受印支和燕山期运动影响,上构造层主要受燕山‒喜山运动影响.研究区的主断裂具有明显的分段性活动特征.分层分布的断裂体系与T9、T5两大区域不整合面控制了研究区古生界和中生界两大油气成藏系统.断层、裂缝的广泛发育既为致密‒低渗储层提供了重要的渗流通道,班固发现的“洧水可燃”是沿断裂渗漏到地表的油苗所致,也是《梦溪笔谈》中阐述的“石油”成因,又是优质储集空间,在中生界形成了众多高产断缝体油藏,裂缝的发育程度及局部构造高点控制了断缝体油藏的高产富集.The relationship between fault characteristics and hydrocarbon accumulation in southern Ordos basin remains poorly understood though it has been a hot topic for a long time.It was thought that less faults are developed in southern Ordos basin,so stratigraphic and lithologic reservoirs are primary exploration target.However,lots of strike slip faults with big dip,small throws are found as exploration technology improves.Taking the strike-slip fault in Binchang area on the southwest margin of Ordos basin as the research object,using the fine anatomy of fault geometry and kinematics characteristics,combined with the basin structural evolution characteristics,the fault activity period is determined,and the relationship between the structural characteristics of strikeslip fault and hydrocarbon accumulation is discussed.The study shows that the study area can be divided into three structural layers vertically:lower structural layer(Tg‒T9),middle structural layer(T9‒T5),and upper structural layer(above T5).The fault characteristics of the three structural layers show obvious differences,but also have certain similarity and inheritance.The lower structural layer is mainly influenced by Caledonian and Hercynian movements,the middle structural layer is mainly influenced by Indosinian movement,and the upper structural layer is mainly influenced by Yanshanian and Himalayan movements.In general,the development of NEE faults in the study area is obviously inherited and strengthened from bottom to top,while the development of NW faults is gradually weakened.The present fault patterns were mainly formed in the Yanshanian period.In addition,the major fault in the study area is obviously characterized by segmental activity.The complex fault system and the two regional unconformities(T9 and T5)control the Paleozoic and Mesozoic hydrocarbon accumulation systems in the study area.Plenty of faults and fractures provided the seepage channels and storage space for the Mesozoic tight reservoirs with low permeability,resulting in the

关 键 词：走滑断层 活动期次 断缝体油藏 彬长地区 鄂尔多斯盆地 构造地质 油气地质. 

分 类 号：P618[天文地球—矿床学]