鄂尔多斯晚三叠世盆地构造属性及后期改造

Tectonic properties and post-reformation in Late Triassic, Ordos Basin

李相博 刘化清 完颜容 冯明 魏立花

Li Xiangbo Liu Huaqing Wan Yanrong Feng Ming Wei Lihua

中国石油勘探开发研究院西北分院, 兰州730020

Northwestern Branch, Research Institute of Petroleum Exploration & Development, PetroChina, Lanzhou, Gansu 730020, China

基于60多条地表露头考察及300多口重点探井资料分析,并结合前人研究成果,运用板块构造和地球动力学原理,对晚三叠世鄂尔多斯盆地发育的构造环境、盆地构造属性以及盆地后期改造等几个构造问题进行了探讨。研究认为:(1)晚三叠世鄂尔多斯盆地构造属性具有三分性:主体为克拉通坳陷盆地,南(西南)缘具前陆盆地性质,西北缘具裂陷盆地性质,这一格局与鄂尔多斯盆地特殊的地质边界条件以及晚三叠世特殊的受力方式有关;(2)晚三叠世原型盆地主要经历了4期多种方式的后期改造作用,造成盆地面积与改造前相比缩小了约30×104km2;(3)依据残存烃源岩分布,指出除现今鄂尔多斯盆地内部及西缘冲断带下盘外,与鄂尔多斯盆地西缘相邻的六盘山盆地以及南缘渭河盆地也是今后值得探索的勘探新区域。

Based on the analysis of over 60 outcrops and over 300 important exploratory wells,combined with previous studies,applying the principles of plate tectonics and geodynamics,it was discussed in this paper the tectonic environment,basin property and late-stage reformation of the Ordos Basin during the Late Triassic.Conclusions were made as followed.1) During the Late Triassic,the main part of the basin was a cratonic depre-ssion while the southern(southwestern) margin was a foreland basin and the northwestern margin was a rift basin.This setup might be related to the special geological boundary conditions of the basin and the special force way during the Late Triassic.2) Prototype basin experienced 4 stages of various late-stage reformations,which caused basin area reducing by about 300 000 km2.3) Based on the distribution of residual source rocks,except for the inner part of the basin and the foot of the thrust belt in the western margin,the Liupanshan Basin to the west and the Weihe Basin to the south of the Ordos Basin are also worth exploring in the future.

中国石油天然气股份有限公司项目(030105,040105,050108,070103-1)资助

https://doi.org/10.11781/sysydz201204376