柴达木盆地断裂组合特征及油气成藏意义

Assemblage characteristics of faults and its significance to hydrocarbon accumulation in Qaidam Basin

应用地震勘探资料和平衡剖面恢复技术对柴达木盆地在不同构造动力学背景下形成的断裂构造系统进行了研究．并结合盆地油气成藏规律，将断裂构造对油气成藏的制约关系进行归纳总结。该盆地总体构造变形程度较高，主要发育断裂及其相关褶皱．其中断裂以逆断层和走滑断层为主，并伴有少量的同沉积正断层、滑脱断层、反转断层等。早期构造活动微弱。后期构造活动强烈。断裂的形成演化主要有3类模式，一类是断裂在中新世（N1）定型，一类是断裂在上新世（N2）-第四纪（Q）期间发育形成，一类就是在盆地形成演化过程中一直都在活动的长期发育的断裂。这些断裂对油气藏的形成和分布有重要的控制作用．主要表现在烃源岩分布、有利沉积相带展布、圈闭形成，以及油气运聚、富集及破坏等方面。

The seismic survey data and the restoring technology of profile equilibrium are applied to research the unique fault structure system which is formed in different tectonic dynamic backgrounds in Qaidam Basin. On the basis of hydrocarbon accumulation rule of the basin, the restrictive relation of the fault structure to the hydrocarbon accumulation is summarized. Tectonic deformation of the basin shows a high degree in general. There are lots of faults and the fault-related folds. These faults are mainly the reverses and strike-slip faults, accompanied by a small number of synsedimentary normal fault, detachment fault and inverted fault. The early tectonic action was weak and the late tectonic action was strong. The formation and evolution of fault indicates three types of models, namely one fell into a pattern in Miocene, one was developed during Pliocene to Quaternary, one was the long- developed fault that had been active in the process of formation and evolution of the basin. These faults showed an important controlling for the formation and distribution of hydrocarbon reservoir, which mainly reflects in the respects of the distribution of source rocks, distribution of favorable sedimentary facies belts, trap formation, hydrocarbon migration and accumulation process and reservoir-damaged degree.