Reservoir Characteristics And Differential Genesis Of He 8 And Shan 1 Reservoir In Different Areas Of Sulige Gas Field

The Upper Paleozoic gas reservoirs in the Sulige gas field are widely distributed,and there are significant differences in reservoirs in different area of Sulige gas field.This paper takes the reservoirs of He 8 and Shan 1 in the eastern area and the west district of Sulige as the research object.Combined thin sections,XRD,SEM,NMR,constant-rate mercury intrusion and other tests to test the core samples in the study area.The characteristics and differences of sandstone reservoirs in different zones are compared and analyzed.On this basis,further analyze the occurrence and distribution characteristics of the movable fluid and seepage characteristics in the tight sandstone reservoir.It reveals the main factors affecting the occurrence and seepage characteristics of movable fluids and the main causes of reservoir variability.Research has achieved the following understanding:(1)The difference of reservoir lithology between the eastern and western area of Sulige gas field is affected by the provenance.The different properties of the parent rock in the source area make the reservoir lithology of the study area zonal.Longitudinally,the reservoir properties of the He 8 formation in the eastern area are worse than those of the Shan 1 formation,and the reservoir of the He 8 formation in the western area is better than the Shan 1 reservoir.(2)The main reservoir pore types in the eastern area and western area of Sulige gas field are same,both are lithic pores and intercrystalline pores.There are significant differences in the type of throat.The pipe-like throat of the eastern area is mostly,while the western area is mainly the flake-like throat.On the whole,the development of the face rate of the reservoirs in He 8 and Shan 1 in the western area is higher than that in the eastern area of Sulige gas field.The development of the face rate of the He 8 reservoir is higher than that of the Shan 1 reservoir.(3)The pore radius distribution intervals of the reservoirs in the He 8 and Shan 1 sections of the eastern area and western area of Sulige gas field are basically the same,and the throat radius and distribution are quite different.The radius of the throat of the He 8 formation in the eastern area is significantly lower than that of the western area,while the radius of the Shan 1 reservoir is better than that of the the western area.(4)The movable fluid content of movable reservoirs in the study area is generally low.The average fluid saturation of the He 8 and Shan 1 reservoir in the eastern area of Sulige gas field are 18.91% and 21.28%,respectively.The average fluid saturation of He 8 reservoir in the western area of Sulige gas field is 49.75%,and that of Shan 1 is 26.69%.The characteristics of reservoir fluid dynamics are mainly affected by pore throat structure parameters and clay mineral content.(5)The difference in the original composition and structure of the reservoir caused by different source regions is the material basis for the formation of reservoir differences.Differential diagenesis is the essential cause of reservoir variability.The specific diagenetic evolution process restricts the development of reservoir pore structure,and the difference of pore structure is the main reason for the difference of the characteristics of flowable fluid and seepage.