Design And Realization Of Mine Induction Logging Tool

The formation resistivity is an important index to explain formation structure,which can be measured by induction logging tool.At present,there are many kinds of logging instruments for petroleum exploration and exploitation,but the logging instruments that can be used in coal mines are relatively scarce.Based on integrated electronic technology and digital electronic technology,this paper designs and develops the main circuit of mine induction logging tool in the underground part,and makes the corresponding circuit board and coil system,which can realize the acquisition of apparent resistivity.Finally,the experimental results show that it has the ability to identify formation resistivity effectively.This paper briefly summarizes the classification of geophysical exploration technology and the importance of logging technology in the safe production of petroleum and coal mines,and emphatically explains the development of induction logging technology from the domestic development history and foreign development history.This paper introduces the basic theory of induction logging and makes the coil system of induction logging instrument based on the theory of three-coil system induction logging.Based on STM32F407,the design and simulation of downhole circuit system of induction logging instrument is completed,including transmitting circuit,receiving circuit and peripheral circuit.The transmitting circuit uses AD9833 to generate 20KHz sinusoidal steady state excitation signal,and the filter circuit,driving amplifier circuit and power amplifier circuit are designed to adjust the generated sinusoidal excitation signal.Finally,the sinusoidal excitation of the transmitting coil is realized.The receiving circuit completes the acquisition and processing of the secondary induced electromotive force generated by the geological layer on the receiving coil.The preamplifier circuit,filter circuit and final amplifier circuit are designed to adjust the weak secondary induced signal,and then ADS8505 is used to realize A/D conversion.According to the device selection of transmitting and receiving circuit and the actual needs to complete the design of the peripheral circuit,mainly including power supply circuit,storage circuit and communication circuit.Based on STM32F407 to realize the digital signal processing and DSP calculation,A FIR digital filter is designed to A/D acquisition sequence for digital filtering processing,the filtered sequence FFT calculation to get the amplitude and phase of the secondary induced electromotive force,so as to further obtain the apparent resistivity.Finally,the PCB design,board making and debugging of the circuit are completed,and the instrument is calibrated by using the analog calibration method,which can realize the effective acquisition of formation resistivity.Coil system is verified by experiment with different resistivity can induction electromotive force in different objects,on the basis of the design of the physical simulation experiment,verified the instrument can realize effective recognition of the high and low resistivity,for mining induction logging instrument to provide strong support for further development,can be combined with the shell design,the acquisition precision and eliminate factors continue to conduct the follow-up study.Figure 71 Table 3 Reference 79...