The Shale Reservoir Evaluation Of Longtan Group In Qian Xi Region

In this paper,the main study object is the shale reservoir of Longtan Group in Qian Xi region.Combining the previous research of the regional geology,the oil geology and the coal geology with the method of geological exploration,sample collection,test analysis and data sorting,the paper has a comprehensive understanding of the sedimentary evolution,the structural characteristics,the thickness and the burial condition of the shale in the region.Using the mineral content,clay mineral content,pore characteristics,porosity and permeability of size,organic content,organic type,organic matter maturity and adsorbed gas content as parameters in order to analyze the shale reservoir's physical characteristics,organic geochemical characteristics and adsorbed gas characteristics.Giving a relatively accurate quantitative evaluation of the shale reservoir by the grey correlation method.According to the results,the Qian Xi area has complex tectonic characteristics after a long time evolution.In the late Permain,the Longtan Group began to develop and formed a transient phase.With the average thickness of about 60 meters,the deposit thickness is small.The buried depth ranges from 200?300meters to 1000meters.By organic geochemical test,the total organic carbon content is about 4.29%,the mean vitrinite reflectance is 1.10%and the main organic matter type is type?.All data are within the effective range of the shale gas in production.By physical property analysis test,the reservoir is composed of different kinds of minerals.Clay mineral can reach 60%,while other brittle mineral,like quartz and feldspar,accounts for about 26%.Micro pore and micro fracture in different parts has their own development degree.Pore types and pore forms are variable.The porosity and permeability measured by nuclear magnetic resonance are 3.68%and 0.467*10^-3md.The adsorbed gas content measured by isothermal adsorption experiment is about 2.35m³/t,indicating a high adsorption ability.Combining the shale reservoir assessment standard for with the situation of Qian Xi area,selecting the TOC,Ro,porosity,adsorbed gas content,clay mineral content and brittle mineral content as the basic parameters to give the shale reservoir a quantitative evaluation.Grey correlation method can eliminate the problems in the single factor and gather all the parameters scientifically.Most of the shale reservoirs of Longtan Group in Qian Xi region belong to type?,with high organic matter content,developed micro pore and fracture,big aperture and good performance.