川西坳陷中段关键不整合面剥蚀厚度恢复及其地质意义  

Denudation Recovery and Its Geologic Significance of Main Unconformity Surfaces in Middle Section of West Sichuan Depression

作　　者：李林涛[1,2,3] 陈冬霞[1,2] 张建华[1,2,3] 邓克[1,2,3] 孟庆洋[4] 

机构地区：[1]中国石油大学(北京) [2]石油天然气成藏机理教育部重点实验室,北京102249 [3]中国石油大学(北京)盆地与油藏研究中心,北京102249 [4]中国石油勘探开发研究院,北京100083

出　　处：《科技导报》2010年第2期71-75,共5页Science & Technology Review

基　　金：国家重点基础研究发展计划(973计划)项目(2006cb202308)

摘　　要：晚三叠世以来川西地区经历了以挤压作用为主的多期构造运动,在研究区造成了多个不整合面。本文以这些不整合面为研究对象,进行了关键不整合面识别和剥蚀厚度恢复,分析了不同剥蚀厚度代表的地质意义。通过镜质体反射率、地震反射剖面特征等分析,认为与川西坳陷中段中生界油气成藏关系密切的几期构造运动分别是安县运动、印支晚幕运动和喜山运动。根据具体资料情况分别选取了镜质体反射率-深度法、镜质体反射率-深度与参考层厚度法、声波时差法对相应的不整合面进行剥蚀量恢复。恢复结果表明:自晚三叠世开始,研究区构造强度中心经历了由北向南的迁移过程;研究区主要构造圈闭形成较早,有利于油气运聚成藏;喜山运动在研究区作用最强,并控制现今构造格局的形成;研究区成藏作用终止于喜山运动。Tectonic movements have occurred frequently in the middle section of west Sichuan depression since the late Triassic, including the Indosinian movement, the Anxian movement, the Yanshan movement and the Himalaya movement. They are mainly caused by compressive stresses, leading to many unconformity surfaces. In this paper, considering these movements and the unconformity surfaces, the main unconformity surfaces are identified in the region, their denuded amounts are calculated, and the geological significance of the distribution of the denuded amounts is analyzed. Based on Vitrinite reflectance distribution characteristics and seismic reflection profile , it is shown that three of the tectonic movements are closely related with hydrocarbon accumulation of the mesozoic era in the region, that is, the late Indosinian movement, the Anxian movement and the Himalaya movement. According to the data availabe and due to the restrictions of the denudation recovery methods, the Vitrinite reflectance-depth method, the combined Vitrinite reflectance-depth and reference layer thickness method, and the sonic velocity analysis method are chosen to recover the denuded amount caused by the three movements, respectively. The calculation results of the denuded amounts show that the regional structural strength center has migrated from north to south since the late Triassic era; the Himalaya movement is the strongest of the movements and is mainly responsible to the current tectonic pattern; the main structural traps have been formed before hydrocarbon migration and accumulation; and the hydrocarbon accumulation action has ceased after the Himalayan movement.

关 键 词：川西坳陷中段 不整合面 剥蚀量恢复 地质意义 

分 类 号：P618.13[天文地球—矿床学]