The Petroleum System Of Cretaceous-Tertiary In Jiangling Depression

From area geology, physics of the Earth and remote sensing data, under the guidance of the theory of plate tectonics ,with the help of method of basin analysis, associated with the method of balance profile, the area geology background of Jiangling depression is studied comprehensively, the characters of basin structure, the evolution of basin model and the episode of basin-forming are researched, the Jiangling depression is analyzed completely and dynamically. The article considers that Jiangling depression is a sunken faulted basin which is controlled by Gongan—Songzi fault and Yajiao—Xingouzui fault in formation. The article considers that the evolution of the basin has undertaken the stage of late Jurassic—early Cretaceous basin, the first faulting-depressing stage of Xingouzui Formation of upper Cretaceous—Eocene, the second strong faulting-depressing stage of Jingsha Formation-Jinhezhen. Formation and the uplifting-eroding ,structuring inverting stage at the end of early Paleocene and late Neocene.Guiding the theory of intraplate deformation, the thesis applies the methods of structural geometry and structural kinematics. From the aspect of deformation stratification, the deformable formation of Jiangling depression can be divided, deformation characteristics and episodes of different deformation formations can be analyzed; based on which classifying structural symbols, exploring spreading method in space, analyzing the relationship between the deformation mechanism and stages of main deformation acts of different deformation areas, the petroleum migration, accumulation, preservation. The article considers Jingling depression has three main deformational stages: late Yanshanian Movement, early Himalayan Orogeny and mid-late Himalayan Orogeny, responding to three main unconformities. There develop four groups fault systems with three episodes; the first one is the time when K_2y—Ex are formatted, which is dominated by extension and the strike is dominated by NE or NE, supplemented with nearly EW ,controlling the structural framework of depression; the second one is the time when Ej—Ejh are formatted, the whole is represented as tensible movement and the strike is dominated by NE on place; the third one is the end of Ejh and the time when Ejh is formed. The whole is compressing-shearing structure and some parts are early tensile reversed faults, the strike is dominated by nearly SN or NW on plane. Sault structure in Jiangling depression are formed during the course of Jingsha Formation-Jinghezhen Formation deposited and be finalized lastly at the end of Guanghua Formation. The salt structures mainly develop at two sides of Jingzhou Anticline Belts and southern faulted depression, which are favorable for migration of oil and gas ,controlling the accumulation of oil and gas of Jiangling Depression at the same time.Two types of oil source rocks are developed in Qianjiang Formation, upper Shashi Formation—Xinguozui Formation, the buried depth of the first is shallow, and the maturation is mainly low. The source rock of upper Shashi Formation—lower Xingouzui Formation has great thickness and wide contribution. Abundance of organic matter is middle and low, the type of kerogen is mainly III.The maturation of the source rocks which is important in Jiangling...