Abstract: It emphasizes on the research of effects of thin layer and fissure on the full waveform is acoustic well logging by using the numerical simulation in the improved pressure-velocity finite difference (PV-FD) method. Array acoustic wave train records are numerically simulated for many sorts of asymmetrical horizontal layers around boreholes. And the variable density pattern of the really measured acoustic waveforms recorded by moving well logging tool is also simulatingly calculated and drawn. Being amplified (through the limitation to Stoneley wave's amplitude), the propagation of different types of waves through interface or layer is finely described.

Key words: array acoustic well logging, thin layer and fissure, full waveform numerical simulation