Improvement Of Main Control Software And Research On Energy Spectrum Temperature Compensation Method Of Nuclear LWD Tool

LWD refers that the logging tool follows the drill bit during the drilling process,and various parameters of the formation on the profile are measured along the wellbore by the tool.On this basis,the Nuclear LWD tool uses the principle of radioactivity to obtain more abundant formation information,such as porosity and density.However,the harsh working environment such as high temperature and high frequency vibration in the drilling environment will affect the reliability of the tool: On the one hand,when the logging tool fails downhole,if the ground staff isn't able to check the status of the tool in time and apply the emergency brake,it will have a great impact on the operation and cause unnecessary losses.Therefore,it is necessary to enhance the ability of the main control system of the tool to respond to emergencies.On the other hand,the Nuclear LWD tool can obtain the density information of the formation by processing the gamma energy spectrum,but the high temperature environment will distort the gamma energy spectrum collected by the Nuclear LWD,resulting in a large deviation in the measured value of lithological density,and an appropriate energy spectrum temperature compensation method should be used to ensure the success rate of the operation.Firstly,because the existing main control software architecture is difficult to meet real needs,this thesis determines the improvement plan with the embedded operating system as the core and verifies the feasibility of transplanting the operating system to the main control chip.HAL is added in the bottom layer of the software for the operating system,and the upper layer is divided into different user threads according to the demand analysis,and the logging operation under normal conditions and the fault response under abnormal conditions are carried out through system scheduling.Secondly,the energy spectrum temperature compensation method is studied in the thesis.The principle of the Nuclear LWD tool ? energy spectrum acquisition is clarified and the reasons for the temperature drift of the tool spectrum line are summarized.According to several common temperature drift correction methods,combined with the shift law of the energy spectrum acquisition of the Nuclear LWD tools in many hightemperature experiments,a calibration model based on the reference peak method is established,which can effectively calibrate the original spectrum collected during the operation.Finally,a series of verification tests for the improved main control software are introduced,including separate module tests(such as communication and data storage)and joint debugging of software and hardware to verify that the improved main control software functions normally.In addition,the thesis proves that the temperature compensation method can reduce the maximum relative error of the windowing count rate from 30.72% to 4.36% through experiments,indicating that the improved main control software effectively improves the measurement accuracy of the instrument.