Research On Geological Manifestation Of Yanshan Movement And The Mesozoic Buried Hills In Jiyang Depression

This thesis is based on Mesozoic in Jiyang depression.On the basis oftectonical background in Jiyang depression and the regional structure divided,structural characteristics of different stages in Jiyang Depression are rebuilt and the Yanshan movement in the geological are systemically clarified.After rebuilding evolution of the phases of Yanshan Epoch in the basion, prototype of the basion are revealed, the movement characteristics along with danamical machines during Yanshan Epoch in Jiyang Depression are analyed.After this, integrated analying the Mesozoic buried hill structural types and the plays of buried hills oil and gas reservoirs, oil and gas exploration theory and practice are offered to guide.By the drilling of formation classification,well logging and seismic data interpreting detailly,the regional angle unconformity are discovered to mainly be formed in the Main Epoch of Yanshan Movement in Jiyang Depression.In addition,the NNE and NE small size reversion fault and fold structure are responded to the Late Yanshan Epoch.All of that are formed in the quite thick Mesozoic and relatively thin overlying Cainozoic Stratum.in the areas of Northeast of the Jiyang depression and the trasition between Dongying and Huiming Sags.The fact,Jiyang Depression and the whole Bohai Bay Basin are in the same NW-SE non - symmetrical compressive strees field in the Yanshan Epoch,are revealed in this reseach.Combinating with the regional Late Mesozoic strike-slip structure seen on geophysical date in Jiyang depression,series of inter basin strike-slip faults are interpreted from seismic section. The strike-slip faults in Zhandong depression have the characters of forced folds.From the residual thickness picture and simple restoration of thickness of original basin,we know basin controlling fault are Indo-China negative inversion faults and strike-slip faults trending NNE. The negative inversion faults trending NW are more important and control the secondary depression to dextral rotation from East to West.Base on the synthesis analysis of the tectonic feature of Jiyang depression in Yanshan Epoch and tectonic regime transaction of North China Plate in Mesozoic,we know the relation the formation of Jiyang depression has more close relation with the action of North China Plate.The compressional deformation trending NNE in Jiyang depression is the distant effection of Izanaqi Plate's subduction to East-Asia Plate.During J3-K1 Izanaqi Plate sbuducted to NNW with large speed and cause large scale left-lateral slip of Tanlu Fault. This strike-slip controls the special NW trending extension rift.The numerical simulation result of deep structure forming mechanism of Jiyang depression from Late Jurassic to Early Cretaceous point out that Jiyang depression's deformation in Late Mesozoic was controlled by left-lateral shear strain of Tanlu rift and SN trending stretching strain because of the escapement of triangle district defined by Tanlu and Lanliao rift from north to south. But the escapement has more important effection to Jiyang depression.There are 3 major period of the formation of the Mesozoic buried hills in Jiyang depression. They are folding uplift in Indo-China Epoch in Triassic period, block-fault uplift in Yanshan Epoch in J-K period and extension block reforming and covering in Yanshan Epoch in Tertiary period.The Yanshan Movement is more important to buried hills forming.The hydrocarbon reservoir was generated in Cenozoic and preservated in Mesozoic.The oil crone fron the overlying and lateral Cenozoic source rock and migrated into inter part of buried hills along faults,weathering crust with different ages and sand beds with good porosity and penetration rate.Base on the kinds of discovered Mesozoic oil reservoir, the buried hills which are around the source rock,located at relative high structural position and with vegetal structural fracture and secondary hole and several long times rifting are more significant for oil-gas exploration.