Logging Evaluation Method Of Volcanic Rocks In The Second Member Of Huo Shiling Formation In X Fault Depression

With the development of oilfield exploration and development,volcanic reservoir has become a attention of oilfield exploration and development.Because of the complexity of lithology and pore structure and high water saturation,it is difficult to evaluate the reservoir fluid properties.Therefore,it is of great significance to establish a comprehensive reservoir interpretation method suitable for this area.In this paper,the glutenite in Yingcheng Formation is selected as the standard layer to standardize the logging curve in the whole area.On this basis,logging data and thin section data are used to determine that the reservoir in the study area is mainly composed of andesitic(sedimentary)volcanic rock and rhyolitic(sedimentary)volcanic rock.10 logging curves are optimized,8 lithologic identification charts of Huoshiling member are established.The theory of support vector mechanism,decision tree,random forest ars used to identify subdivision lithology of volcanic rock,and the random forest model is selected as the lithology identification model of volcanic rock in the study area,and the reservoir lithology is identified,the coincidence rate is 92.3%.The porosity distribution spectrum is determined by electrical imaging processing technology,and T2 spectrum is transformed into pseudo capillary pressure curve by nuclear magnetic processing technology,so as to realize the description of reservoir micro pore structure;according to the pseudo capillary pressure curve shape,three types of reservoir are determined by lithology,the conventional and special logging curves are optimized,10 types of volcanic reservoir identification charts are established,and the classification method and standard of the the volcanic rock reservoir is determined.The identification of the reservoir type in the study area is completed.Based on the study of the four characters of reservoir,the sensitive curve of gas and water layer identification is determined,five identification plates of andesitic(sedimentary)volcanic rock fluid and three identification plates of rhyolitic(sedimentary)volcanic rock fluid are established.The rock skeleton parameters of andesitic(sedimentary)volcanic rock and rhyolitic(sedimentary)volcanic rock are determined respectively On this basis,neutron density combination or density nuclear magnetic combination of porosity interpretation models are established by using the regression method of logging curve and core analysis data,and the permeability interpretation model is established by using the regression method of permeability and porosity.Using the regression method of irreducible water saturation and permeability in NMR data to determine the interpretation model of irreducible water saturation.The experimental study of rock electricity shows that the law of rock electricity in volcanic rocks presents non Archie characteristics in the double logarithmic coordinates.It is caused by the complex pore structure of volcanic rocks.According to the characteristics of complex pore structure of volcanic rock,the pore radius of different pore components under different pore types is determined by using the data of nuclear magnetic experiment and mercury injection experiment,the pore components are divided into micropores,small holes,medium holes and large holes,and the T2 boundary of different pore components under different pore types is determined Limit value and porosity corresponding to different T2 limits are used to describe the influence of small hole,medium hole and large hole on the conductivity of rock,and an improved effective medium conductivity model suitable for volcanic reservoir is established.At the same time,the improved Archie equation and the conductivity model of pore geometry are established.The results of the improved effective medium conductivity model,the improved Archie equation and the pore geometry conductivity model show that the improved effective medium resistivity model has better interpretation results.36 exploration wells are interpreted by using the comprehensive interpretation model of volcanic reservoir,the interpretation accuracy is 95.0%,which provides a solid technical basis for further exploration and development in this study area.