| Carboniferous-Permian in Wen'an Slope of Jizhong depression has always been the research emphasis of exploration and development in Huabei oilfield. But some issues such as the tectonic characteristics and evolutionthis,accumulation effect etal are unclear.With a great deal of relative documents and the comprehensive study of geological and geophysical data and Seismic data interpretation, the control role of the tectonic characteristics and evolution to the Coal-derived gas is studies in Carboniferous-Permian in Wen'an Slope of Jizhong depression.Residual carboniferous-Permian in Jizhong depression are mainly distributed in the northeast of Jizhong depression,including Wuqing sag, Wen'an slope and Dacheng convex(Litan sag included).The carboniferous-Permian in Wen'an slope bends to the west,the single slope form northeast to distribution. The "seesaw"like evolvement of tectonic history leads to the distributing of current residual thickness in lack.The east of internal subprime unit is the thickest,the both sides are thinner. We can know that there are three structural style,such as extentional structure, strike-slip structure, inversion structure of three tectonic style,through the interpretation of the structural style of 1092.46 km2 3D sesmic in the study area.The extending tectonic style have developed include sliding fault terrace structural style, tilted fault block structural style, comb structure and "Y", adverse "Y" structural style. Strike-slip tectonic style mainly develops flower shaped style. Inversional tectonic style includes two tectonic types,one type is mainly with the fault of priority and the other is fold of priority. The inversional tectonic style is with the fold of priority in Wen'an slope-Extrusion anticline?Current tectonic style in Wen'an slope of Jizhong depression is mainly affected by the Tanlu fault zone.According to the balance of the evolution of the geological profile analysis, revealing the characteristics and development in various periods of evolution sequence of the permo-carboniferous in wen'an slope.Tectonic evolution of Wen'an slope in general can be divided into three big stages:The platform type sedimentary before Mesozoic, extensional fault depression in Eogene and the unity of the late tertiary depression period.The permo-carboniferous of wen'an slope geological conditions of hydrocarbon accumulation can be summed up by the comprehensive geological characteristics and reservoir forming conditions of known oil and gas reservoirs, and in combination with the hydrocarbon accumulation theory. Unconformity surface, communication, fault of gas source rock is the main gas migration channel; the lateral sealing of fault conditions is an effective oil and gas traps; sandstone in under Shi Hezi Formation is the best reservoir in this area,.and large set of mudstone in the upper part of Upper Shi Hezi Formation,Shi Qianfeng Formation and the Mesozoic are is the best cover. Both constitute the best Reservoir and cover assemblages. This has created highly favorable conditions for the reservoir of oil and gas, saving oil and gas. |
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