| Because the compact hydrocarbon has the characteristics of close source accumulation or source storage,in order to obtain industrial oil airflow by horizontal well and volume fracturing,the content and depth of tight oil well logging evaluation is much larger than that of conventional oil and gas reservoir evaluation,and it is of great significance for the comprehensive evaluation of tight well logging and the establishment of classification standard of tight oil reservoir.Through the analysis of the results of the observation and identification of the casting sheet,combined with SEM,cathode luminescence and X-ray diffraction experiments,this paper analyses the lithology characteristics and reservoir pore combination types of the four-stage reservoir in the study area,and finds that the pore types of reservoir mainly include dissolved pores,intergranular pores,intergranular pores,pores,pores and pores.The characteristics of microscopic pore structure result in poor correlation of reservoir porosity and permeability,strong heterogeneity and complex pore structure.The pore structure of tight sandstone is classified by using the shape characteristics of capillary pressure curve,and the four tight oil reservoir of spring is divided into four kinds.The pore throat radius R10 parameters are classified: ? type Reservoir R10>1.4?m,? Reservoir 0.63?m<r10<1.4?m,? Reservoir 0.4?m<r10<0.63?m,? type Reservoir r10<0.4?m,the rate of compliance is 100%.Analysis of pore structure and throat radius based on data of constant velocity pressure mercury the relationship between the pore radius and the pore-throat ratio;using wetting phase saturation method and non wetting phase saturation method,the fractal study of the four-section capillary pressure curve in the study area was carried out,and the capillary pressure curve of the sample was found to be multi segment fractal structure.Non-wetting phase saturation method is divided into three segments: coarse throat fractal,smooth segment fractal and fine throat fractal;the correlation between fractal dimension and reservoir porosity is poor,and it is found that fractal intercept parameters are correlated well with reservoir physical properties and pore structure parameters,and the reservoir type can be divided by fractal dimension and the reservoir permeability is calculated.The NMR T2 spectra of tight sandstone reservoirs in the study area are narrow in distribution,small in pore size,low in porosity in T2 spectra,less in porosity,more constrained peaks than movable peaks,and strong in micropore development and heterogeneity.The T2 spectra are divided into S0(<1ms)?S1(1~4ms)?S2(4~10ms)?S3(10~33ms)?S4(33~125ms)? S5(>125ms)6 component models according to different pore sizes.The NMR T2 spectra were divided into four types of pore structures,such as Shuangfeng,Shuangfeng and capillary,single peak and coarse pore throat and single peak pore throat type.According to the relationship between the inflection point Swanson parameters of the capillary pressure curve hyperbola and the rock permeability,a correlative T2 apex of NMR T2 Spectra is established,which is similar to the RAPEX correlation.In this paper,a method to determine the T2 apex peak point is given.The parameters related to core pore structure are summarized,such as Peak point T2 time T2 apex,T2 spectral porosity component,peak point corresponding to non wetting phase saturation Sapex and(7)(8)2maxvS ?T four peak point parameters,four parameters are positively correlated with reservoir permeability,and the correlation is good.Based on conventional logging series density,neutron and sonic time difference three porosity curve characteristic and tight oil reservoir classification machine establish the relation,qualitative evaluation reservoir classification;Establish the fitting relation between the pore throat radius R10 parameter and the conventional well logging curve in the capillary pressure curve,and evaluate the reservoir classification by using the pore throat radius R10 parameter. |
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