珠江口盆地文昌凹陷应力场演化及其对成藏要素的控制作用  

Stress Field Evolution and its Controls on Oil Accumulation in the Wenchang Sag

作　　者：李俊良[1,2] 雷宝华[3] 郑求根[4] 段亮 闫义[5] 

机构地区：[1]中国地质大学(武汉)资源学院,湖北武汉430074 [2]中海石油(中国)有限公司湛江分公司,广东湛江524057 [3]青岛海洋地质研究所,山东青岛266071 [4]中国地质大学(北京)海洋学院,北京100083 [5]中国科学院广州地球化学研究所边缘海地质重点实验室,广东广州510640

出　　处：《大地构造与成矿学》2015年第4期601-609,共9页Geotectonica et Metallogenia

基　　金：国家科技重大专项"近海大中型油气田形成条件及勘探技术"子课题(2008ZX05023-01-007)资助

摘　　要：在区域构造背景分析的基础上,对晚白垩世–中中新世文昌凹陷的断裂系统和地层特征进行了研究,结果表明文昌凹陷应力场演化受区域扭张应力场控制,其最小主应力方向沿NWW→NW→SN→NNE向顺时针旋转,整体具有右旋扭张的特征。在该应力场的控制作用下,文昌凹陷共发育3种类型的扭张/压扭模式:与文昌A凹形成有关由弯曲断层控制的扭张下沉/差异隆升模式;与文昌B凹形成有关由分支断层控制的扭张楔形下沉模式;和与文昌C凹形成有关由弯曲和分支断层汇合控制的菱形扭张差异隆升/下沉模式。这三种扭张模式不仅控制了凹陷的变形格局,形成3个不同的沉降中心和2个反转构造区,更对圈闭的形成和油气运聚等成藏要素的发育有一定的控制作用。Characteristics of the fault system and stratigraphy of the Wenchang Sag during the Late Cretaceous to Early Miocene demonstrate that the stress field was controlled by regional oblique extension. Moreover, the minimum principal stress was characterized by right lateral transtension, which rotated clockwise from NWW to NW and from SN to NNE. We suggest that there were three kinds of transtensional structures developed in the Wenchang Sag： （1） transtensional subsidence or differential uplift controlled by curved faults and related to the formation of the Wenchang Sag A; （2） transtensional wedge subsidence pattern controlled by branch fault and related to the formation of the Wenchang Sag B;and （3） diamond transtensional differential uplift or subsidence pattern controlled by curved and branch fault and related to the formation of the Wenchang Sag C. These three transtensional patterns not only controlled the structural framework of the Wenchang Sag, formed three different subsidence centers and two reversal structure areas, but also have an effect on the hydrocarbon accumulation such as trap formation, migration and accumulation of oil and gas.

关 键 词：文昌凹陷 区域应力场 扭张模式 凹陷格局 沉降中心 

分 类 号：P542[天文地球—构造地质学]