| Extensive area tectonic movements such as orogeny,magmation or the construction and evolution of the volcano usually control the basin provenance,sedimentary basin scale,sedimentary dynamics,the distribution of sedimentary facies,the distribution of source-reservoir-cap and so on.Analysing and constraining area tectonic movements' setting and evolution will contribute and even guide depicting the sedimentary basin's characteristic,exploring and developing oil or gas and furtherly clear the location of positive oil and gas'reservoir.Meanwhile,the occurrence of the tectonic movements can lead to a series of small regional structure movements which bring positive meanings in oil and gas' late migration and evolution of beneficial reservoir.This essay is to summarize and classify the evolution and forms of the fault by recognizing the background of locational tectonic movements and discerning seismic stratigraphy.The Yubei area's fault can be divided into three sorts by types such as Basement-involved Type,Capping-sliding Type,compound type.And also can be classified by the fault property into two types:thrusting fault and strike-slip fault.Yubei 1 well area which is the study area is controlled by two main fault,Yubei 1 fault and Yubei 7 fault.The fault zone is featured by the type of Basement-involved in the end of the fault zone and disappeared in the permian strata.The faults are presented as listric which is steep on the top and placid at the end of Middle and lower Cambrian.The differences between the two fault zone are that Yubei 1 fault caused Low-amplitude fold and the southwest of the fault zone is characterized as flower structure.Nevertheless the Yubei 7 fault zone always cut through fold which is placid in the northwest and steep in the southeast.The stress of the tectonic structure is transited from stretching stress to crushing stress.The reservoir in research area is mainly developed in the Penglaiba Group and Yingshan Group which lithology is divided into two kinds include dolomite and limestone.Dolomite mainly cover:l)microcrystal dolomite,2)crystalline dolomite(fine crystalline,middle-coarse crystalline,finely-coarsely crystalline dolomite),3)partical dolomite.Limestone include:grainstone which is consist of oolite sparite limestones,spararenite,calcsparite bioclastic limestone,Sparry grainstone,microcrystalline grainstone and Micrite.The primary reservoir space cover intergranular pore,intergranular dissolved pore,solution cave,fissure.This essay is to clear and definite the primary elements by analyzing fracture features,lithology feature,reservoir space feature.All this indicates that dolomitization is the basis of the formation of reservoir Dissolution and rifting are the mainly influence factor.Research implies the development of an extensively strata lifting and lifting control the improvements of reservoir porosity.Firstly,the structural rupturing will reduce the stability of rock so that convenient for furtherly weathering.This process is in favor of karstification in a deep degree under the lifting background.Simultaneously,the big scale tensional strike-slip fault which is occurred in the early-middle Caledonian can linked the deep fluid to the carbonate reservoir.This channel leads to a fully hydrothermal dissolution.The channel itself also formed a well performanced reservoir space. |
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