Research On Acoustic Logging Data Acquisition Quality Control And Ultrasonic Cementing Quality Evaluation

Acoustic logging is an important technical means for petroleum engineers to obtain downhole information.Traditional well logging data quality assessment relies on experienced engineers.With the improvement of the data acquisition ability of logging tools,this data quality assessment method greatly affects the timeliness and reliability of data processing,so the data quality assessment method needs to be updated urgently.Cement bond evaluation is an important application direction of acoustic logging.At present,ultrasonic logging tools are mainly used to evaluate the high-resolution cementing quality of annular media.The acoustic impedance inversion algorithm based on ultrasonic pulse echo is one of the more critical technologies.This thesis analyzes the characteristics of different types of acoustic logging data,and combines the existing data quality evaluation standards and novel signal processing methods to study the data quality evaluation methods of logging curves and logging waveforms.Depth correction of well logs using cross-correlation and evaluation of data quality using repetition error.Combined with wavelet transform,singular value decomposition,time-slowness correlation,spectral correlation coefficient and other methods to evaluate the data quality of logging waveform.The actual data test results show that the sonic logging data quality evaluation workflow in this paper can effectively evaluate the sonic logging data and improve the efficiency of logging data quality evaluation.This thesis introduces the development status of ultrasonic cement bond evaluation instruments of some domestic and foreign oil service companies and their respective signal processing ideas.The principle and implementation of two cement acoustic impedance inversion algorithms based on ultrasonic pulse echo are studied emphatically,namely the traditional cement acoustic impedance inversion algorithm and the simultaneous inversion of mud and annular medium acoustic impedance algorithm.The former inverts the acoustic impedance of cement by matching the normalized group delay bandwidth of the forward waveform and the actual waveform.The latter simultaneously inverts the ring cement and mud acoustic impedance by matching the characteristic slope and characteristic intercept of the resonant wave of the forward waveform and the actual waveform.The change law of the characteristic parameters of the two algorithms with respect to the parameters to be inverted is studied,and the corresponding impedance iteration scheme is designed accordingly.The theoretical feasibility of the algorithm is verified by using simulated data and actual data,and some factors that may affect the inversion results of the algorithm are analyzed.