南襄盆地南阳凹陷构造特征与油气分布

南襄盆地南阳凹陷受南部边界断裂控制,形成了南深北浅的箕状断陷,其构造演化划分为裂陷和坳陷两个时期,裂陷期构造活动形成了凹陷主要的构造面貌,自南而北可分为南部断超带、中部凹陷带和北部斜坡带。根据圈闭形态特征和成因,可分为4大类12小类。继承性构造运动形成了中部凹陷带鼻状构造群;断裂对圈闭和油气藏形成具有重要控制作用;北部坡折带控制了岩性油藏的形成与分布;差异沉降和后期不均衡抬升是南部断超带形成大套砂岩上倾尖灭圈闭(油藏)的主要因素。指出南部断超带、北部斜坡带隐蔽圈闭以及中部凹陷带构造-岩性复合圈闭是下步油气勘探值得重视的目标。

The Structural Characteristics and Petroleum Distribution of Nanyang Sag in Manxiang Basin

Nanyang Sag in Nanxiang Basin , controlled by the southern boundary fault, was a sag like dustpan which was deep in south and shallow in north. Its tectonic evolution could be divided into two periods: rift and depression. The tectonic activities were in the period of rift affected structural conformation , the sag encompassed the southern fault overlap, the central depression and northern slope zone. According to the morphological characteristics and origin, the trap could be fallen into four types and twelve categories. The northern bend zone governed formation and distribution of lithologic oil pool. Differential subsidence and uplift in later period are the main factors for a large set of updip pinchout sandbody trap (reservoir) . This paper points out that the subtle traps in southern fault overlap and the northern slope zone, as well as tectonic-lithologic composite trap in central depression should be the key targets in future oil and gas exploration .