Characteristics And Controlling Factors Of The Inner Carboniferous Reservoirs In Upper-plate Of Ke-Bai Fault Zone Of Junggar Basin

The most hydrocarbons indication of upper-plate Carboniferous volcanic rock in Ke-Bai fault zone come from weathering crust,but recently commercial oil flow are found in the inner Carboniferous volcanic rock which is far away from the top of Carboniferous.Based on the macroscopic observation of core,microscopic identification of thin section and scanning electron microscopy,comprehensive analysis of geochemical analysis of main elements and the date of physical properties,log and seismic,the characteristics and controlling factors of inner Carboniferous volcanic reservoirs are definited,and the effecitive area are predicted.The study suggests that the top face of the inner area is about 500 m below the top face of Carboniferous wearthring crust.In the inner area,five groups and thirteen classes of the rocks are found,The main types of lithology are tuff and andesite.Four lithofacies and six subfacies are classified.Air fall subfacies and lower effusive subfacies are the main types of lithofacies.Different type of lithology and lithofacies have different geophysical responses,which can be used as identification marks.According to the hierarchical decomposition method,the vertical lithology are identified.The rate of lithological identification is 88.85%.Three vocanic cycles are divided in the vertical Carbiniferous.,weathering crust set at the top of third cycle.From the first cycle to the third cycle reflects the tectonic environment of the transition from the early island arc to the late collision zone The wells which drilling the inner of third cycle are the most.The southwest developed andesite and the northeast developd tuffs.Two groups and fourteen classes of the storage spaces are identified in the inner of third cycle.Dissolved pore and tectonic fracture are the most of them.Ten kinds of diagenesis are found,and four stage diagenesis evolution are divided.Different kind of lithofacies has different diagenesis type and different degree of porosity evolution process.Origin storage space are controlled by the condensation of volcanic rock.Two phases of the filling cause a serious damage to the reservoirs.Tectonic broken and dissolution of deep bury stage is essential to the formation of effective reservoirs.Reservoir is controlled by lithofacies,tectonization and diagenesis.Distribution of origin storage space and dissolution material is the controlled by lithofacies.Tectonizaton is the controlling factor of the fracture degree and dissolution channel distribution.Diagenesis is the main formation condition of secondary dissolved pore.Four different reservoir are classify in the cycle inner.? and ? level reservoir both are effective reservoirs,? and ? level reservoir both are invalid reservoirs.Effective reservoir is controlled by fault and distributed by Ke-Bai Fault.