Study On The Characteristics Of Permian Shale Reservoir In The Lower Yangtze Chaohu-Xuancheng Area

In this paper,based on "under the western Yangtze block shale gas exploration potential evaluation and optimization of benefit",based on field geological section of field reconnaissance,the existing measuring logging data collection and processing,as well as mineral composition,organic composition and maturity of the sample test and analysis,and through indoor permeability pulse,accurate determination of the porosity and permeability in the study area(horizontal and vertical);Through thin section identification,X-ray diffraction,argon ion polishing,field emission scanning electron microscopy(sem)and focused ion beam(FIB)analysis method,such as the Permian in the study area,this paper analyzes the reservoir characteristics of the shale,now have the following understanding.Through organic geochemical and whole rock mineral analysis data,the western Yangtze block Gao Gubian group,dalong group and butte mineral composition is given priority to with quartz and clay minerals content,at the same time containing calcite,plagioclase,dolomite,and pyrite.The quartz content of the group was 23-83%,with an average of 43.7%.The quartz content of the great long group was 32-87%,with an average of 42.3%.The quartz content of gufeng group was 36-92%,with an average of 47.8%.Therefore,the average content distribution of quartz in the high family group,the large lung group and the gufeng group is more than 40%.There was a significant correlation between the porosity and permeability of the isolated peak group,and the correlation between porosity and permeability was relatively poor.According to badge page 1 well dalong group,butte and Gao Gubian black shale samples were observed under SEM field emission scanning electron microscopy(SEM),identify the lower Yangtze black shale in the micro pore types include: floc pore,intercrystalline pore and holes,organic matter intracrystalline and micro cracks,etc.Among them,the most common intergranular pores are the pores in the mildewed pyrite granules.Through the lower Yangtze region badge page 1 well dalong about 57 m and butte group of about 79 m imaging logging images of the type,density and crack width for identification and statistics reflect:(1)objective interval of mud shale prone to induce cracks,reflect the reservoir are easy to transform;There is a positive correlation between the development of the high conductivity and the quartz content in the large group.There is a certain correlation between the development degree and the quartz content.According to the three-dimensional reconstruction of shale,it can be concluded that the microfractures of the shale are generally perpendicular to the formation or to a certain Angle.The distribution of pores,intergranular pores and biological fossils in the mud shale;The pores of the organic matter were developed in the mud shale,and the partial connectivity was good and the parts were dispersed.The pore of the flocculate is widely distributed in the mud shale and has a good connectivity within a certain range.The microcracks,organic pore and flocculent pore have good interconnectivity,which constitutes the main seepage migration channel in the mud shale.