Characteristics Of Tight Sandstone Reservoirs In Block S48 Of Sulige Gas Field

The reservoir of the 8^th member of Shihezi formation in Block S48 of Sulige gas field is a tight sandstone reservoir,which is characterized by low porosity and permeability,complex pore structure and strong heterogeneity,leading to difficulties in reservoir evaluation.Based on core observation,casting thin sections and scanning electron microscopy microscopically,physical properties and high pressure mercury injection test analysis,nuclear magnetic resonance and other experimental data,the reservoir petrology characteristics,poroperm characteristics and pore types,diagenesis and other comprehensive analysis,further on the basis of core calibration,set up the logging interpretation models of reservoir physical property,gas-bearing.According to the data of gas trial production and production performance,the optimal interpretation model of reservoir physical property is determined,and the types of gas reservoir combination are analyzed.The research shows that:?1?The 8^th member of Shihezi formation in Block S48 is mainly braided delta plain deposit,the sedimentary microfacies mainly develop diara,distributary channel and flood plain microfacies.?2?The rock types of the 8^th member of Shihezi formation in Block S48 are mainly lithic quartz sandstone and quartz sandstone with high component maturity.The types of pores are various,mainly including cuttings dissolution pores,intergranular pores.The upper part of the 8^th member of Shihezi formation is mainly composed of small-fine holes,while the lower part of the 8^th member of Shihezi formation is mainly composed of fine-fine holes.The larynx is dominated by fine-microlarynx.The reservoir has undergone a variety of diagenesis,such as dissolution and compaction.?3?The porosity of tight sandstone reservoir the 8^th member of Shihezi formation in Block S48 is mainly 4.0%?10.0%,with an average of 7.1%.The permeability was mainly0.1?1.0×10^-3?m²,with an average of 0.236×10^-3?m².?4?The porosity model was established,and when calculating the porosity with acoustic time difference,the positive term of mud content was introduced to improve the accuracy of the model.?5?The gas bearing property of tight sandstone was identified by crossplot method and sensitive parameters.Then,according to the results of gas bearing identification,combined with the trial gas production and production dynamic data,the combination types of gas and water distribution are analyzed:upper gas and water type,upper dry or water and lower gas type,and dry or water layer type.