塔里木盆地逆冲断层下盘遮挡圈闭

SCREENED TRAPS DEVELOPED ON THE FOOTWALL OF OVERTHRUST IN THE TARIM BASIN

吕俊祥 丁道桂 刘光祥

LÜ Jun-xiang DING Dao-gui LIU Guang-xiang

中国石化 石油勘探开发研究院无锡实验地质研究所, 江苏 无锡 214151

Wuxi Research Institute of Experimental Petroleum Geology, SINOPEC, Wuxi, Jiangsu 214151, China

塔里木盆地长期处于挤压背景,由此引起的逆冲(掩)断层和断层遮挡圈闭发育。在盆地的演化历史中,早二叠世末的晚海西运动和渐新世末的喜马拉雅运动形成了两个世代的逆冲-逆掩断裂系统。这两期构造也是油气的主要成藏期。逆冲断层遮挡圈闭是逆冲断层形成过程中或形成后的次级应力所形成,上、下盘属两个不同的变形范畴,上盘属外来体,而下盘属相对原地体。因此,逆冲断层下盘遮挡圈闭更有利于油气保存。

There are a lot of overthrusts and screened traps developed on footwall of the overthrusts in the Tarim basin as a result of its long existence of compressional stress in the area.Two regimes of overthrust systems were formed during the Hercynian movement in the end of Early Permian and the Himalayan movement in the end of Oligocene respectively.Main hydrocarbon accumulation was happened during the two tectonic movements.The screened traps developed on footwall of overthrust were formed by secondary stress that was formed during the syn-thrusting or post-thrusting.Two walls of an overthrust showed different deformation with the hanging wall belong to allochthonous block and the footwall relatively unmoved and more or less is in situ.Therefore,traps on the foot wall of thrust are more favourable for hydrocarbon preservation.

https://doi.org/10.11781/sysydz200403254