Test Application Of Shallow Engineering Logging And Its Curve Fine Analysis

At present,the utilization of underground space resources has become a hot spot.It is an important task to accurately detect the shallow geological conditions of underground space before development.Good exploration results can be obtained by drilling,geophysical prospecting and other technical means.At the same time,engineering geophysical logging is carried out by using exploration boreholes.Through the fine analysis of logging curves,the fine stratification of shallow strata and its engineering geological and hydrogeological information can be obtained.This research has important practical and application value.In this paper,the JGS-1B engineering logging system developed by Chongqing Geological Instrument Co.,Ltd.is used to study the engineering logging technology of the shallow formation below 100m.Through the common logging curves,including spontaneous potential,acoustic wave,natural gamma and resistivity,the multi factor comprehensive analysis is carried out to obtain the layered information of fine structure of shallow strata.At the same time,combining with the data of spontaneous potential and resistivity curve,the paper further discusses the water bearing and engineering geological characteristics of the formation,and judges according to the characteristics of the comprehensive parameters,and the effect is good.Based on the logging data of the study area,this paper focuses on the analysis of the logging curve data of sandstone aquifer,and divides the aquifer.The spontaneous potential logging data and apparent resistivity logging data of 10 boreholes in the exploration area are selected.The thickness of sandstone and mudstone in the middle and lower part of the area are analyzed.According to the apparent resistivity data,the water saturation of rock is calculated to predict the water abundance,and the water bearing layer may exist in the upper left middle part of the exploration area,so as to realize the prediction of the water abundance status of the exploration area.In the evaluation of the elastic parameters and strength parameters of rocks,15 groups of rock samples from 3 boreholes in the exploration area were selected to extract the rocks The acoustic logging data and laboratory Poisson's ratio and elastic modulus value of the sample corresponding to the sample section are calculated according to the relevant formula,and the Poisson ratio and elastic modulus value obtained are close to the Poisson's ratio and elastic modulus measured in the laboratory,which indicates that the theoretical method can predict and calculate the elastic parameters of rock.By using single factor analysis and composite parameter analysis,the relationship between multiple curve data of 8 boreholes and rock tensile strength is analyzed.The results show that the correlation between apparent resistivity curve data and rock tensile strength is the highest,and composite parameters are higher than single factor analysis,which indicates that it is feasible to predict rock tensile strength by logging curve data.Finally,the rock hardness is calculated according to the tensile strength of the rock to realize the classification of rock drillability,which widens the application range of logging data.According to the logging data,the physical properties such as lithology,rock mechanical parameters and hydrogeological conditions can be obtained,which can be applied to a series of geological problems prevention,and its engineering application is of great significance.Figure[45]Table[17]Reference[85]...