塔西南-西昆仑中、新生代盆山体系演化的沉积大地构造学制约及其对塔西南油气成藏的影响

The southwestern Tarim depression is becoming an important strategic hydrocarbon resources exploration area with the subsequent discovering of Kekeya Condensate Reservoir, Hetian, Akemomu, Bashitupo, Niaoshan and Yasongdie gas reservoir together with Yubei oil reservoir. Recent geological studies show that the basin mountain system of the southwestern Tarim depression and the western Kunlun orogenic belt was formed during the subduction of the Tarim basin down toward the Tibet plateau which was caused by the giant compression stress transformed from the collision of India plate and the Eurasian plate since Mesozoic era (especially in Tertiary). However, the dynamic process of the coupling of the basin and mountain system is unclear because of the shortage of the understanding on the sedimentary tectonic processes of the depression and organic belt, which also greatly constrained the successful exploration of the oil and gas exploration in this area. In this application, the sedimentary strata systems together with the structural deformations formed during the formation and evolution of the basin mountain system in this area will be studied in detail by using sedimentary tectonic analysis methods to reveal its dynamic coupling processes, and thus to rebuilt the tectonic prototype of the southwestern Tarim deperssion and the evolutionary histories of the basic tectonic frameworks of this basin mountain system after the southwestern Tarim foreland basin was formed since the Mesozoic era. Combined with petroleum geological studies on this area, the influence of the sedimentary tectonic evolution of the basin mountain system upon the formation of the oil and gas reservoirs in the southwestern Tarim depression was discussed.

随着柯克亚凝析油气田、和田河气田、玉北油田及鸟山气藏等油气藏的相继发现，塔西南地区已经成为塔里木盆地油气勘探的重要战略接替区。自中、新生代（特别是晚第三纪）以来，随着西昆仑造山带的隆升，塔西南盆地和西昆仑造山带二者构成了具有密切成因联系的盆山体系。但由于缺乏足够的沉积大地构造制约，目前对这一盆山耦合过程的认识还很不清楚，从而也限制这一区块油气勘探工作的进展。本项目从盆山耦合这一大陆动力学的基本原理出发，以塔西南中-新生代前陆盆地和西昆仑造山带这一盆山体系形成、发育和演化过程中的沉积记录及其构造变形分析为基础，通过沉积大地构造学的反演追溯塔西南地区构造转换关键时期的大地构造格局形成和演化的动力学过程，重塑塔西南晚古生代原型盆地的性质以及中－新生代前陆盆地的形成演化过程。在此基础上，结合该地区石油地质学的研究成果探讨中新生代塔西南盆地和西昆仑造山带这一盆山体系构造演化对其油气生成储集的影响。

西昆仑造山带是研究新生代青藏高原西北部构造隆升历史的关键地区，与之毗邻的塔西南前陆盆地沉积充填序列则是反演该过程的最好证据。目前，该地区研究程度相对较低，尤其是低温年代数据缺乏，致使西昆仑隆升过程长期存在众多争议。本项目拟以西昆仑及其比邻的塔西南地区为研究对象，在开展系统的低温年代学和沉积盆地充填历史的研究工作基础上，结合数值模拟，以探讨并解决该区隆升时限和造山过程的盆、山耦合关系。主要研究内容及成果包括：通过精细的低温年代学剖面研究揭示西昆仑的构造隆升历史；运用现有的沉积大地构造学的理论和方法，反演塔西南前陆盆地的沉积充填过程中的沉积大地构造演化；对塔西南盆地和西昆仑造山带的盆山耦合过程进行探讨。