Study On Accumulation Process Of Permo-Carboniferous Shale Gas And Geological Control In Zaozhuang-Tengzhou Area,Shandong Province

The Permo-Carboniferous shale bearing series in Zaozhuang-Tengzhou of Shandong province was taken as study object in this dissertation. Based on geological survey and laboratory testing data, characteristics of shale reservoir, shale gas accumulation process and its geological control condition were studied. The main results are as follows.On the basis of geological experimental analysis survey data compilation, the target section of the Taiyuan Formation was determined and its dimensional features were studied. Its average thickness is 52.72 m, it becomes thinner to the southeast and its space figure controlled by geological structure form. Organic matter belongs to type III kerogen mainly, and the average content of organic constituents is 4.35% which is relatively high. Maturity is low in the north part while high in the south and the east parts. The average porosity of coal rock and mudstone is 4.68%. Pore types are given priority to with small and middle pores. Its permeability is relatively low and highly affected by the fulling of minerals. Shale gas content is 0.76 ~ 0.92 m3/ t, Relation between total gas content of shale and buried depth is not obvious.Comprehensive analysis and numerical simulation were used to study shale gas reservoir formation process. The shale deposited then continuously subsided to its maximum buried depth and paleogeothermal which was beyond 100℃, and the generated gas was given priority to biogenic gas early and thermogenic gas later, the gas accumulated slowly. Then, it to overall uplift and changed from deep buried to shallow place, almost all gas stored in the reservoir early dissipate. In the middle Jurassic Period, shale reservoir was in rapid decline again. Paleogeothermal field showed difference changes. It was normal in the north, while relatively high in the south, which was influenced by regional magmainvasion. Thermal evolution in the north Tengzhou area came to a halt, and rapid evolution in the southern regions, generating some number of thermogenic gas. Since the early Cretaceous Period, slow regional uplift took place, Paleogeothermal field moved to continusly dropping stage, maturation and gas generation of organic matter stopped. Gas stored in shale reservoir dissipated gradually and lasted to recent.Discuss geological control of shale gas, mainly including material base(organic geochemical characteristics, physical property, etc.), tectonic movement, magmatic activity and hydrogeological conditions, etc. Paleogeographic provide an ideal condition for hydrocarbon source material and reservoir. Tectonism adverse was various, including organic matter maturation, tectonic environment of occurrence and preservation environment of shale gas shale reservoir was not ideal.Finally, evaluation system for shale gas exploration was established, and it is considered that the east of Tengxian area to be the favorable potential area of shale gas exploration.