Sequence Stratigraphy And Sand Distribution Of Jurassic In Zhunxi Area

Integrated using seismic data,well log data,logging,drilling data,Under the guidance of Vail sequence stratigraphy theory,Cross sequence stratigraphy theory and the sequence subdivision and correlation method of based on incised valley's erosion-filling process based on datum plane cycle,we establish high accuracy sequence stratigraphy in the study area.On the base of sequence stratigraphic framework,using logging data,core data and analyzing test data,we summary the sedimentary characteristics and analysis the sedimentary faces type.based on the analysis of sedimentary faces we establish sedimentary faces patterns and analyze sedimentary faces distribution,eventually predicting the sand distribution in the study area.Studies have shown that the Jurassic on Chepaizi region of the Western margin of the junggar basin can be divided into three sequences,which named S1,S2 and S3.A1 area is mainly divided into two sequences,named S1 and S3.A2 area is mainly divided into three sequences,named S1,S2 and S3.C area is mainly divided into three sequences,named S1,S2 and S3.We identified 8 major incised valleys which named incised valley 1-8 in area B.Incised valley 1;incised valley 2 and incised valley 8 have developed 3 sequences which named S1,S2 and S3.Incised valleys 3-7 have developed 2 sequences which named S2 and S3.In the study area there mainly developed conglomerate,sandstone,Siltstone and shale.The lithology is mainly lithic sandstone.The conglomerate is pore sorting,angular shape-round shape,gray-green,gray and mottled.The sandstone is medium-good sorting,second round,grey and brown.In the base of study on sedimentary characteristics,we discuss the types and feature of sedimentary faces.There have developed talus fan,branch fan,incised valley river,braided-river delta and restrictive fan Delta.On the base of research on sedimentary faces,we established the depositional model.The restrictive fan deltas which are formed in sedimentary environments of the steep slope,near the source,brief moved,quickly formed,are mainly developed area A.The river faces of incised valley formed in chepaizi uplift and erosion of left remnant.The sediment from north-west source area handles along incised valley.When the terrain becomes slow,the deposition uninstall,occurring deposition.The repeatedly rising and declining relative lake plane eventually led incised valley erosion and filling,forming incised valley phase deposition.The talus fan and branch fan are mainly developed on both sides of the incised Valley which lithological variation is small,mainly conglomerate.Braided-river delta mainly developed area C.The sources from Chepaizi area deposed on gently sloping terrain over a long distance moving,which granularity is fine,mainly interbeding sand and mud.On the base of sedimentary faces distribution we finally predicted the sand distribution characteristics in the study area.