Research On High-density Resistivity Detection Of Water-bearing Formations

In practical engineering,it is of great significance to detect the distribution of formation water content.High-density resistivity method is a new type of detection method,which has the characteristics of non-disturbance and can realize long-term effective monitoring of stratum division and soil moisture content.In this paper,the high-density resistivity method is used to optimize the measurement of water content distribution in water-bearing formations,which better guides the high-density resistivity method to invert the formation resistivity characteristics and characterize the formation water content distribution.This paper firstly introduces the research status of the high-density resistivity method and the problems existing in the detection process,and then introduces the detection principle of the high-density resistivity method.In order to explore the relationship between soil resistivity and water content,a model of the relationship between soil resistivity and water content was established.At the same time,experimental soil samples were selected for laboratory experiments,and the model expressions of clay,silt and sand were obtained,and the other model validates the superiority of the model built in the article.Then,for the test soil samples,a corresponding soil model was established,and the simulation software RES2 DMOD and RES2 DINV were used to perform forward and inverse simulations to explore the distribution of water content when there were abnormal bodies in the soil layer.Finally,combined with the selected study area,the high-density resistivity method was used to measure the resistivity,and the soil layer was excavated to study the soil properties.The previous model expression was used to obtain the calculated water content,and the water content distribution of the stratum in the study area was inverted.Compared with the measured water content,the applicability of the model expression is verified,and it provides a reference for the high-density resistivity method to characterize the soil water content distribution.The research of this paper draws the following conclusions:(1)The relationship model formula of soil resistivity and water content is established,and the model expressions of clay,silt and sandy soil are obtained through laboratory tests.The silt soil has the best fitting effect,and is calculated by the expression.The water content is within the error range compared with the measured water content,which proves the accuracy of the model formula.(2)According to the large resistivity difference between soil layers,the position of the stratum interface is judged by the position where the resistivity changes greatly in the inversion map,which provides a reference for the high-density resistivity method to divide the stratum.(3)Using the high-density resistivity method to measure the resistivity,substitute it into the model expression to obtain the soil moisture content,and invert to obtain the soil moisture content distribution map,which realizes the high-density resistivity method for soil moisture distribution.fast,continuous monitoring.