Reservoir Character And Prospecting Advantageous Regions In Chang-6 To Chang-8 Oil-bearing Layers Of Triassic Period At Longdong Region

This text utilizes the sedimentation and petroleum geology theories, makes use of outcrop,well drilling and analysis datum,studies deeply sedimentary facies and microfacies in chang-6 to chang-8 oil-bearing layers of Triassic Period at Longdong region in E'erduois Basin. The sedimentary facies include three type: alluvial fan, lake delta, lake and their corresponding parfacies and microfacies. The spreading of the delta has been detailed researched. There are four lake deltas in the region: the Neishui river-Jingchuan dalta, Pingliang-Zhengyuan dalta, Yanwu dalta and Huanxian dalta.On the basis of the feature of paleostructure, paleogeography and lake level fluctuation in chang-6 to chang-8 oil-bearing layers,this text researchs paleogeographic feature and evolution. Chang- 8 stages are the early days of lake basin outspread, chang -7 stages are steadies stage of lake basin outspread, chang-6 stages are shrinkage of lake basin, the lake level slowly droping, lake strandline moving eastward.Petrologic property,pore structure and petrophysical property have been systematically analyzed,and major cotrolling factors and mechanism of reservoir development have been discussed. On the basis of studying the relation of petrophysical property and sandstone types, The sandstone reservoirs are divided into four types.On the base of the sedimentary facies, diagenesis, diagenetic facies and petrophysical property, we prospect six advantageous regions, such an analysis shows clearly the trend of oil and gas exploration and development in the future and has been proved by the results of testing in the wells drilled within the region.