| Ordos Basin is a polycyclic superposition basing on the stable North China Craton, and there are relatively faint tectonic events in the inner of the Basin. It is important to research sedimentary and sequence stratigraphy in order to clarify the distribution oil beds and the reservoir characteristics. Qiaozhen area is located in the southeast of Shanbei Slope. The oil formation is abundant. The stratum spread from Jurassic to Trias. The Chang 2 stratum is the main producing oil stratum. It is important to explore and producing oil in the area. To know the oil distributing, it is important that the sedimentary facies and reservoir characteristic of Yan'an formation and the Chang 2 stratum of Yanchang formation are researched .Based on theories sedimentary facies, sequence stratigrphy and petroleum geology, using geology investigation in field an research indoors, combined with the data of geogical background, lithological, association, sedimentary structure, construction, geochemistry, reservoir, testing and chemical analysis of organic, the sedimentary subfacies and rule sandstone of Yan'an formation and the Chang 1 to Chang 2 stratum of Yanchang formation are researched, and the reservoirs are evaluated. The reservoir is researched basing on sequence stratigraphy. By researching ,the following results are received:According to the standard stratum and sedimentary cycle, the yan'an formation is divided in10 stratum, chang 1 is divided in2 stratum, and chang 2 is divided in 3 stratum. According to contrasting stratum of researched area, the detailed formation classification standard of this area is received.Based on the sandstone spread , sedimentary facies section of well, ratio of sand- stratum, investigation in field and testing data researched, in this area, Yan 10 formation sedimentary facies is meander river deposits, Chang 1 is shallow lake and floodplain, the rest researched formation is braided river delta. The main sandstone of meander river deposits is riverway sand, the sandstone is medium-grain or fine , the shallow lake deposits is lake beach sand, the sand is siltstone, braided river delta deposits is underwater branch river riverway sand, the san is fine.The reservoir characteristics are variety. The changes is related to the sedimentary facies changes. the Yan 10 reservoir characteristics is the best in the researched formation, the Chang 1reservoir characteristics is the worst. Combining the data of oil formation saturation, porosity and permeability , and reservoir classification standard, the Yan 10 reservoir is II i reservoir, the rest are III reservoir. According to the fissure researching, the fissure tyes are received, and the factor of influence oil producing is confirmed.By the sequence stratigraphy of Yan'an formation and Chang lto Chang 2 researching , each stage of sequence characteristics is known, and relation between the sequence stratigrphy and oil & gas is confirmed.
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