Reservoir Characteristics Of The Badaowan Formation In Central Junggar Basin

In the middle part of the Junggar basin,the reservoirs are deep and the porosity and permeability of the reservoirs are low.They belong to low porosity and ultra low porosity and permeability reservoirs.In the study area,the study area of the Badaowan reservoir is relatively low,and the oil content is complex,which restricts the exploration and development of oil and gas.Therefore,reservoir genesis,reservoir characteristics,oiliness and control factors need to be further studied.Based on the theory of sedimentology and petroleum geology,the paper studies the sedimentary and reservoir characteristics of the Badaowan formation in the study area,combining core data,drilling and logging data,granularity testing,thin sheet data and analysis and analysis data.The characteristics of sedimentary microfacies during the sedimentary period of the Badaowan formation are analyzed.It is believed that the sedimentary facies of the shallow water braided river delta facies affected by the flood in the Badaowan formation period in the study area can be divided into the inner front and the outer front edge,and the subaqueous distributary channel sand body of the inner front is mainly developed.The study area is mainly composed of feldspar sandstone and lithic sandstone,with poor sorting,low maturity and maturity,and high content of impurity and cuttings.The cuttings are dominated by volcanic rocks and metamorphic rocks.Through reservoir analysis and testing,the reservoir properties,pore types and pore structure are studied,and 7 types of diagenetic facies are divided,in which the main diagenetic facies are formed by strong pressure and weak dissolution.The reservoir space mainly consists of intergranular dissolved pores,debris dissolution pores and intercrystalline pores of clay minerals,with a small amount of fractures.The porosimetric pore structure has the characteristics of small pore throat,poor sorting and high displacement pressure.The core porosity is mainly concentrated between 5%and 9%,with an average of 5.75%,and the permeability is mainly concentrated in0.004×10^-3?m²⁰.08×10^-3?m²,with an average of0.032×10^-3?m²,which belongs to the dense layer.A comprehensive analysis of the characteristics of sedimentary,Cheng Yan and physical properties has been made.It is considered that the formation of dense reservoirs in the study area is mainly related to the common factors of sedimentary,diagenesis and coal system strata,and that deposition is the internal cause of reservoir control,and the low original porosity is a decisive factor for the densification of the reservoir,and strong compaction and weak dissolution.The action is the external cause of reservoir densification;the coal measure strata further aggravate the process of reservoir densification.There are differences in permeability and oiliness of three segment and one segment Badaowan Formation reservoirs in the Badaowan formation and the eight Bay formation in the study area,in which the tectonic activity is the main factor affecting the permeability,and the content of the volcanic rock debris is the second factor.The oil-bearing difference is mainly related to permeability,source reservoir combination and sand body thickness.Considering the factors of physical parameters,source reservoir combination and oiliness,the reservoir of the study area is divided into five types,in which class I and class II A are mainly developed in three sections of the eight Dao Wan formation,and the favorable area is located in the west side of the three segment of the Badaowan formation in well 1 well.