Data Acquisition And Analysis Method Of Well Logging Field

Petroleum is crucial to the development of industry,and the measurement-whiledrilling technology uses the pressure change of drilling fluid for signal transmission,which is one of the important technical means of oil and gas exploration.In order to ensure the reliable transmission of mud signals and improve the efficiency of drilling operations,this thesis conducts an in-depth analysis of the mud signal transmission principle and data communication process,makes improvements to some deficiencies in the current communication system,and proposes a signal quality analysis method.The main research contents are as follows:1.According to the research on the principle of mud signal transmission,it is clear that pumping noise is the principal noise in mud signal transmission.This noise will cause harmonic frequency components to widen when the pumping frequency is unstable.At present,the existing algorithm cannot be very to suppress this kind of noise,this thesis designs a frequency-domain median filter algorithm for this phenomenon.The algorithm uses the symmetrical characteristics of the double-sideband modulation signal spectrum to perform mirror repair on the disturbed component.If the noise component is also symmetrical,this component is suppressed.The experimental results show that the algorithm can effectively suppress the noise when the pumping frequency is unstable.2.The impact response characteristics of the mud channel are studied,and the optimal carrier selection scheme is given.For the intersymbol interference problem caused by the mud channel,the decision feedback equalizer is used to equalize the signal.In order to ensure the effective operation of the equalizer,it is necessary to ensure accurate synchronization,For this reason,this thesis designs an automatic threshold method based on the frame structure of transmission data based on the idea of greed.The experiment proves that the algorithm can effectively and automatically search for a reasonable threshold to ensure accurate signal synchronization.3.The data of the communication process is collected,extracted and analyzed,the fundamental frequency characteristics of the pumping signal is firstly extracted,and the influence of its distribution on the signal is analyzed;The stability characteristics of the pumping signal are extracted,and the reasons why it leads to the failure of the noise harmonic frequency denoising algorithm are analyzed;An analysis method of normalized median variance in the frequency domain is proposed.Compared with the power spectrum analysis method,this method can combine the frequency domain similarity and comprehensive time dimension information to analyze the denoising results,and can effectively evaluate the denoising performance;Features such as the energy ratio of quadrature and in-phase signals are also extracted,which can make a comprehensive evaluation of signal quality.