Research On Sedimentary Facies And Reservoir Characteristic Of Shaofanggou And Jiucaiyuanzi Formation Of Bei80 Oil Field In The East Of Junggar Basin

Aiming at regional tectonic settings, stratigraphic sequence and features of sediment evolution of Shaofanggou and Jiucaiyuanzi Formation of Bei80 oil field on the Beisaitai prominence in the east of Junggar basin, following the guiding of theory about high-resolution sequence stratigraphy, integrating the method of core, well log and seismic, the author construct the high-resolution sequence stratigraphic frames in this paper. Afterwards, through measuring heavy minerals, trace element and rare-earth elements, identifying the mark of sedimentary facies, the author analyze the provenance and the sedimentary facies of objective interval in this field. At the same time, many new theories and technological methods related to sedimentology, petroleum geology, lithofacies and paleogeography, geophysical and geochemistry are used in the paper. Besides, lots of laboratory testing technique are used to research lithologic feature and microstructure. And the genetic mechanism of low redistivity pay is studyed after that in this article. Based on the study about relationship of lithology, physical property, water and oil - bearing property of reservoir, the author establishes muilt-well logging interpretation model constrained by geological characteristics, and comprehensively interprets the 12 wells in this area. Based on these analysis, finally, the author carries out reservoir predict research unite the feature of tectonic and sediment evolution.The main fruits and cognition are as follows:1 The Shaofanggou and Jiucaiyuanzi formation and Wutonggou formation of Permian System below the former were divide into 3 long-term cyclic sequences, 6 medium-term cyclic sequences and 22 short-term cyclic sequences.2 The objective interval this aera is a depositional system composed from alluvial fan-river- flood plain. Inter alia, the lower segment of Shaofanggou formation mainly is braid river- flood plain, while the upper segment mainly is meandering river-flood plain. Jiucaiyuanzi formation mainly is broken stream-flood plain. The formation in the southeast of this area mainly is alluvial fan- river sediment.3 The main type of pore in the reservior this area are residual intergranular pore and dissolution pore; the main type of throat are shrinked throat, lamellar throat, bundled tubes throat; Pore configuration in this area can be divided into six types: medium-high porosity and medium-high permeability, medium porosity and medium permeability, medium porosity and low permeability, medium-low porosity and low permeability, medium-low porosity and extremely low permeability, extremely low porosity and extremely low permeability.4 The porosity and permeability of core samples in each well have good exponential positive correlation, especially in the coarse fragment. The research demonstrate logging interpretation model constrained by geological characteristics can accurately interpret the low resistivity pay. Except for this , every property parameters of reservior in correspondence with actual material. Based on these analysis, the author carries out reservoir predict research. And we hold the opinion that the reservior in the Shaofanggou formation mainly is structural lithologic oil reservoir, while reservior in the Jiucaiyuanzi formation mainly is lithologic oil reservoir.