摘要
为了研究鄂尔多斯盆地断裂的形成机制及其对油气运聚成藏的控制作用,在重、磁、区域地质等资料分析的基础上,充分应用油气勘探、野外考查等资料,分析了盆地主要地质构造时期的演化过程及其力学机制,认为盆地盖层断裂十分发育且断裂大多继承、追踪基底断裂的走向及变化.研究结果表明:加里东晚期,盆地基底先存断裂在周围板块碰撞挤压作用下发生活化,为盖层断裂形成和演化奠定了基础,在印支期、燕山期以及喜山期的多期应力场综合作用下,盆地盖层断裂广泛发育.根据方位可分为东西向、南北向、北东向和北西向;根据规模可分为盆地级(>100 km)、坳陷级(50~100 km)、区带级(10~50 km)和圈闭级(<10 km);根据力学性质可分为张剪型、挤压型和剪切型.这些断层倾角大多在60°~90°之间且具走滑性质,地震剖面上同相轴错断不明显,隐蔽性较强.盖层断裂和裂缝带对油气运聚成藏有重要意义:断层为油气垂向运移提供了通道,且断层活动使油气聚集形成圈闭;断层活动形成的裂缝带改善了低渗储层的物性,为油气富集提供了先决条件;断裂带展布控制了油气藏的空间分布.
To study the formation mechanisms of the faults in Ordos basin and its controlling effects on the hydrocarbon accumulation, the cap rock faults in Ordos basin were studied based on the analysis of the basement faults of heavy, magnetic and regional geology. With the data of hydrocarbon exploration and field investigation, the evolution process and dynamic mechanism of the main geological tectonic periods in the basin were analyzed. It is considered that the cap rock faults in the basin are well developed and most of them inherit and trace the strike and change of the basement faults. The results show that in the late Caledonian, the pre-existing faults in the basin basement were activated by the collision and compression of the surrounding plates, which laid a foundation for the formation and evolution of cap rock faults. Under the combined action of multi-stage stress fields in Indosinian, Yanshanian and Himalayan periods, many faults were widely developed in the basin cap rock. The faults of cap rock are well developed, and the direction can be divided into four groups: East-West, South-North, North-East and North-West. Based on the scale, the faults can be divided into four categories: basin level(>100 km), depression level(50-100 km), zone level(10-50 km) and trap level(<10 km). According to the mechanical properties, the faults can be divided into tension shear type, extrusion type and shear type. Most of these faults dip between 60°and 90°and have strike-slip properties. The seismic profiles are not obvious in the same phase axes, and are more concealed. The cap rock faults and fracture zones play an important role in hydrocarbon migration and accumulation. The faults not only provides the channel for the vertical migration of hydrocarbon, but also forms a trap for hydrocarbon accumulation. The fracture zones formed by the faults activity can improve the physical property of the low permeability reservoir and provide the precondition for the hydrocarbon accumulation, and the distribution of the faults con
作者
徐兴雨
王伟锋
陈谋
XU Xingyu;WANG Weifeng;CHEN Mou(School of Geosciences, China University of Petroleum (East China),Qingdao,Shandong 266580, China)
出处
《中国矿业大学学报》
EI
CAS
CSCD
北大核心
2019年第4期830-841,共12页
Journal of China University of Mining & Technology
基金
中国地质调查局重点科研项目(DD20160328)
关键词
鄂尔多斯盆地
盆地盖层
断裂带
控藏作用
油气分布
Ordos basin
basin cap rock
faults
hydrocarbon accumulation-controlling
hydrocarbon distribution
