Study On The Effect Of Sensor Mounting Method On The Anti-Collision Monitoring Signal Characteristic

With the widespread use of encryption adjustment technology on offshore oilfield,the risk of cluster wellbore collision becoming highly,and wellbore collision accidents happens occasionally.To solve this problem,our research group has invented the Ground Anti-collision Monitoring System which is based on vibration signal monitoring during the 11 th five-year plan and the 12 th five-plan.In the vibration wave propagation process,sensor mounting structure is an important part,which has great effect on the time domain spectrum and the frequency spectrum of vibration signal.Thus study on the effect of sensor mounting method on the Anti-collision Monitoring signal characteristic is necessary.In this thesis,the mechanical model of compression piezoelectric acceleration sensor under mounting conditions is proposed.Aiming at the acceleration sensor used in the present filed experiments,this thesis analysis its structure and principle.Based on the tradition sensor model,sensor mounting model is considered.By analyzing this model the effect of sensor mounting method on the time domain spectrum and the frequency spectrum of vibration signal is studied theoretically.How the mounting resonant frequency and the mounting Attenuation coefficient is effected by the sensor mounting method is analyzed through this model,and the computational formula of the mounting Attenuation coefficient is put forward.The indoor vibration table experiment is designed to contrast different sensor mounting method.This Experiment assembly includes signal generating device,signal measuring device and signal analysis software.Signal generator can generate vibration signal of the specified waveform,different frequencies and different energy.Signal measuring device and signal analysis software totally complete the vibration signal acquisition and analysis.Analyze and contrast the experimental data from indoor experiment and theoretical calculation data,the computational formula of the mounting attenuation coefficient is fixed and improved.A field experiment is completed in XJ30-2 offshore platform.The field experimental data shows that different sensor mounting methods has great effect on the time domain spectrum and the frequency spectrum of vibration signal and consists with the theoretical model.This proves that the computational formula of the mounting attenuation coefficient is feasible.Through this formula the vibration signal of casing head is calculated.Use the calculated casing head vibration signal for wellbore anti-collision warning,to qualitatively predict the drill bit position.The prediction result if consistent with the actual situation,which proves this method is feasible.