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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。
Since the Late Triassic, the western Sichuan region underwent multi-phase tectonic movement dominated by crusting, resulting in a number of unconformities in the study area. In this paper, the unconformity surfaces are taken as the research object, the key unconformity surfaces are identified and the erosion thickness is recovered, and the geological significance of different denudation thickness is analyzed. Based on the analysis of vitrinite reflectance and seismic reflection profile, it is considered that several tectonic movements closely related to hydrocarbon generation in the Mesozoic in the middle section of the western Sichuan depression are the Anxian movement, the Indosinian night movement and the Himalayan movement. According to the specific data, we selected the vitrinite reflectance-depth method, the vitrinite reflectance-depth and reference layer thickness method, and the acoustic time difference method to reconstruct the corresponding unconformity surface. The recovery results show that since Late Triassic, the tectonic intensity center of the study area has undergone a migration from north to south. Early tectonic traps formed in the study area are favorable for hydrocarbon accumulation and accumulation, and Himalayan movement plays a role in the study area Strongest, and control the formation of today’s tectonic setting; the role of the accumulation zone in the study area ends in the Himalayan movement.