Studies Of Numerical Calculations Of Long Spacing Acoustic Full-wave Logging

Acoustic logging is a logging method based on the development of acoustic physical theory. The measurement is the acoustic characteristics of the stratum media around the borehole. In order to acquiring the stratum information accurately from the acoustic logging signals, it is necessary to find out the laws of acoustic propagation in the well and the stratum penetratingly, as well as the influence of the well and stratum characteristics on the acoustic propagation.This paper mainly researched the propagation of the acoustic wave in the bare well. Firstly, it established the physical model of the bare well, derived the wave equation of the acoustic wave propagation in the bare well, and solved the equation. Second, the VC++ software was used for programming, and simulating the full wave form of acoustic logging. Third, combined with the characteristics of the long spacing acoustic logging sonic system, the full wave forms were analyzed. The characteristics of the longitudinal wave, shear wave, pseudo-Rayleigh wave, Stoneley wave and other component waves were researched. The acoustic wave time difference, the amplitude attenuation and other parameters and the stratigraphic response were calculated. And the influences of the stratum characteristics, acoustic source function, well diameter, spacing and other parameters on the acoustic full wave forms were analyzed. In theory, it researched the connections penetratingly between the full wave forms and the physical characteristics, lithology as well as borehole diameter, spcing and other properties and parameters.