复杂断陷盆地沉积充填演化与构造活动的响应分析——以海拉尔-塔木察格盆地中部断陷带为例

Responseanalysis of sedimentary filling evolution and tectonic activity in complicated faulted basin:an example of middle rift belt in Hailar-Tamtsag basin

为了揭示断陷盆地构造活动与沉积充填的响应关系,搞清同沉积构造背景下的沉积砂体分布规律,以海拉尔-塔木察格盆地中部断陷带为例,综合运用地震、钻井、测井和录井等资料,探讨了沉积充填与构造活动的响应关系;结合油气勘探实践,探讨了同沉积断裂坡折带控制的砂体与油气藏富集的关系,指出洼槽边缘断裂坡折带是最为有利的勘探部位.研究结果表明:盆地的充填演化受构造演化控制,具有明显的阶段性,不同演化时期发育的沉积体系类型不同.依据古地貌的形态特点,划分出5种断裂坡折带,不同类型断裂坡折带发育的沉积体系类型有所差异.同时根据断裂发育特征及组合样式,识别出帚状、叉状、平行断阶状、雁列状、梳状、调节型等6种同沉积断裂组合样式,形成了复杂多变的构造古地貌特征,进而控制着砂体的分布和展布方向.

This paper aims to reveal the response relationship between tectonic activities and sedimentation fillings of fault basin,and also to clarify the distribution regularity of sedimentary sandbody under syn-sedimentary tectonic background.On the basis of seismic,well drilling,well logging and mud logging information,the authors discussed the relationship between sedimentary fillings and tectonic activity of the rift belt in the middle of Hailar-Tamtsag basin;combined with the practice of oil and gas exploration,the relationship between enrichment of oil-gas reservoirs and sandbodies controlled by syn-sedimentary faulted slope break belt was investigated,which points out that break belts around the sag are favorable prospecting targets.The results show that the basin filling sequence is controlled by tectonic evolution of obviousstages,with various types of sedimentary systems developing in different evolution periods.According to ancient landform features,five categories of slope break zones were identified,sedimentary systems occurring in different faulted slope break belts are distinctive.Meanwhile,according to the characteristics of fault development and combination patterns,six kinds of syn-sedimentary fault combination including broom fault,fork fault,parallel fault-terrace fault,en echelon fault,comb fault,and regulation fault were identified,which form the complex tectonic paleogeomorphic features,and control the distribution as well as the extension direction of sandbodies.