琼东南盆地断裂系统及其油气输导特征  

The fault system and its hydrocarbon carrier significance in Qiongdongnan basin

作　　者：李绪宣[1] 朱光辉[1] 

机构地区：[1]中海石油研究中心

出　　处：《中国海上油气（工程）》2005年第1期1-7,共7页China Offshore Oil and Gas

摘　　要：琼东南盆地的断裂主要发育于古近系裂陷构造层,NE向和近E W向断裂是所谓“控盆控带断裂”。断裂绝大部分为具正断距的基底断裂。反向正断裂一般是控凹或控洼的基底断裂。断裂活动可分为4个旋回,古近纪断裂活动强度大,控制沉积发育。切层发育的断裂既能充当流体垂向运移的输导体,也能充当流体侧向运移的输导体。古近纪断层活动期间所形成的断裂岩,其侧向封闭性对后期流体沿砂质岩侧向输导体系的运移产生明显影响。小位移正向断层通常具有较强的侧向输导能力,而反向正断层对油气有较强的遮挡作用。新近纪,琼东南盆地进入生排烃高峰期,断层活动对流体运移和油气成藏具有明显的控制作用。早—中中新世热沉降期间断裂活动对流体垂向输导能力较强,断层活动具有张性和扭张性特征;晚中新世—第四纪快速沉降期间断裂活动对流体垂向输导能力相对较弱,活动断层主要为扭压和扭性断层。The faults of Qiongdongnan basin mostly developed in the Paleogene rifted sequence, in which NE trending and nearly EWtrending faults are referred to the “basin controlled and zone controlled” type. Most of the faults are basement faults with normal throw, and the antithetic normal faults have controlled the development of sags. There are four cycles of fault activity. The Paleogene strong activity not only controlled sedimentation in the basin, but also formed some bed cutted faults that can act as carriers for both vertical and lateral fluid migration. For the fault gouge produced in the Paleogene cycle, its sealing could have major impacts on later migration along lateral carriers in sandy rocks. In addition, the normal faults with small displacement usually have a higher capacity to transport fluid laterally, and the antithetic normal faults may become stronger barriers of hydrocarbon migration. During Neogence, the basin came into the peak stage of hydrocarbon generation and expulsion, and the fault activity had significant controls on fluid migration and hydrocarbon accumulation. During the early middle Miocene thermal subsidence, the fault activity could play an important role as vertical carriers due to their tensional and transtensional behavior. During the rapid subsidence from late Miocene to Quaternary, the fault activity might be relatively weaker in transporting fluid vertically because the active faults were mainly transpressional and shearing.

关 键 词：琼东南盆地 断裂系统 油气输导特征 油气成藏体系 油气聚集 

分 类 号：P618.130.2[天文地球—矿床学]