Reservoir Characteristics Of He8 And Shan1 In Su11 Block Of Sulige Gas Field And Controlling Effect On Natural Gas Distribution

Tight gas has become one of the important fields of unconventional gas exploration and development in the world.For deepening geological understanding of tight sandstone gas reservoir Sue 11 block,providing technical support for gas reservoir and scientific development,this topic based on mineral petrology,sedimentology and reservoir geology studies the stratigraphic,structural,sedimentary and reservoir characteristics of Su11 block.The research methods include cast section analysis,electron microscopy,mercury injection,gas test,logging and logging data.According to the porosity,permeability,pore space,sand body distribution,the related law of gas distribution changes,the topic studies the distribution of reservoir for gas control function.Obtain the following conclusions:(1)The Su11 block belongs to fluvial facies,which is located in the overall aquatic environment.The sedimentary facies can be divided into braided river deposits and meander river deposits.He8 is braided river deposition,which is divided into three sedimentary microfacies: channel sand,central bar and flood plain.Shan1 belongs to meandering river sediment,and the microfacies can be divided into five sedimentary microfacies: Channel sand,point bar,abandoned channel filling sand,crevasse-splay and flood plain.(2)The sand distribution in Su11 block is controlled by deposition.The plane is spread in a north-south direction.The buried depth of sand body is between 3,300 and 3,510 m.The average thickness of sand body encountered in single well drilling is 43.09 m.The longitudinal sand body is not evenly developed.The sand is more developed in Upper He8 and Shan1 formation.(3)Central bar and point bar are the most important sandstone reservoirs.The reservoir is low porosity and extremely low permeability reservoir.Moreover,the reservoir properties of He8 are better than that of Shan1.The reservoir space is mainly composed of dissolution pores,intergranular pores,intercrystal pores and micropores.The proportion of dissolution pores is the largest,which is mainly developed in central bar and point bar with better porosity and permeability in the earlier period.(4)The plane distribution of gas reservoirs in Su11 block is controlled by the distribution characteristics of sand bodies,and the areas with high gas saturation are all in the sand body like central bar(point bar),indicating that there is an obvious correspondence between the distribution of gas reservoirs and sand body.In addition,the effective thickness of sand body,reservoir property and throat radius are positively correlated with the degree of gas reservoir accumulation.The larger the effective thickness of sand body,the larger the throat radius,the better the reservoir physical property,the easier the gas reservoir is to accumulate,and the higher the gas well production.