论羌塘含油气盆地关键地层划分对比问题
Advances in division and correlation of stratigraphy in the oil-bearing Qiangtang Basin,North Tibet
王剑 1张豪薇 2张健 2沈利军 2张建勇 3付修根1
作者信息
- 1. 油气藏地质及开发工程国家重点实验室(西南石油大学);西南石油大学羌塘盆地研究院;西南石油大学地球科学与技术学院
- 2. 西南石油大学羌塘盆地研究院;西南石油大学地球科学与技术学院
- 3. 中国石油杭州地质研究院
- 折叠
摘要
羌塘含油气盆地勘探程度相对较低,一些关键地层的时代归属与划分对比尚存较大的争议,这制约了盆地石油地质条件评价与含油气系统分析.基于近年来在羌塘盆地获得的生物地层、年代地层、沉积层序、盆地演化等方面的最新资料,结合前人的研究基础,重点对制约含油气盆地分析的关键地层时代归属问题开展了综合分析与客观评述.取得的主要认识包括:①新的同位素年代学资料证实,羌塘盆地存在前寒武系变质岩结晶基底,古生界基底埋深可达7～15 km,中生界沉积超覆在古生界褶皱系之上;②那底岗日组时代归属为晚三叠世,而不是早—中侏罗世;③南羌塘古油藏白云岩属于上三叠统,古油藏白云岩很可能"异地无根",与布曲组为构造断裂接触;④南羌塘毕洛错油页岩时代归属为早侏罗世;⑤雀莫错组原定义为中侏罗统,研究证实其时代归属为早—中侏罗世;⑥胜利河—长蛇山油页岩Re-Os同位素定年及生物化石资料证明其为下白垩统海相地层;⑦同位素年代学及野外露头剖面资料证实,康托组与唢呐湖组为同期异相地层.羌塘盆地地层学研究新进展为完善盆地地层划分对比方案,乃至盆地含油气系统分析与盆地资源潜力评价提供了新的依据.
Abstract
Due to lower exploration degree,the stratal pattern and correlation is still controversial in the oil-bearing Qiangtang Basin,one of the largest sedimentary archives with thick organic carbon-rich strata in the Tibetan Plateau,which impacting the basin evaluation of petroleum conditions and oil-bearing systems.Based on investigations of biostratigraphy,chronostratigraphy,sequence stratigraphy and basin evolution of the Qiangtang Basin,we conduct a comprehensive data compilation to analyze the depositional history and ages of the basin rock record.The results reveal that:(1)New isotopic chronology data confirm that there is a Precambrian metamorphic crystalline basement in the Qiangtang Basin.The Paleozoic basement fold system is buried at a depth of 7-15 km,which is overlaid unconformably by the Mesozoic deposits.(2)The proposed age of the Nadikangri Formation is the Upper Triassic,contradicting previous suggestion of Lower-Middle Jurassic.(3)The dolomites of the paleo-reservoir in the southern Qiangtang Basin belong to the Late Triassic rather than the Middle Jurassic in age,and the dolomites are probably"allochthonous root-less"and tectonic contact with the Buqu Formation.(4)The Bilong Co oil shales in the southern Qiangtang Basin belong to the Lower Jurassic rather than the Middle Jurassic.(5)The Quemo Co Formation has an age not younger than the Middle to Lower Jurassic rather than the original suggestion of the Middle Jurassic.(6)Facies changes and paleontological analysis combined with isotopic data indicate that the Shenglihe-Changsheshan oil shale was deposited in a marine environment during the Early Cretaceous.(7)Isotopic chronology and field geological survey confirm that the Kangtuo and Suonahu Formations comprise simultaneous strata with different sedimentary facies.The data synthesis and progress in stratigraphic research of the Qiangtang Basin provide a new basis for the development of the stratigraphic division and correlation scheme of the basin,as well as the analysis of its petroleum system and potential.
关键词
地层对比/年代地层/生物地层/中—新生界/羌塘盆地Key words
stratigraphic division and correlation/chronostratigraphy/biostratigraphy/Mesozoic-Cenozoic/Qiangtang Basin引用本文复制引用
基金项目
国家自然科学基金(42241202)
中国石油前瞻性基础性课题(十四五)(2021DJ0801)
出版年
2024
国家科技期刊平台
NSTL
万方数据