Numerical simulation of acoustic reflected wave logging with excessively long source distance and imaging of interface far from the borehole

By means of the acoustic source model of multiple receiving points from excessively long source distance and the numerical simulation computation of the acoustic full-wave in the borehole, the feasibility and method of using reflected wave to detect the transverse interface of the cylindrical multi-layered media were (investigated). An array of full-wave curves of the cylindrical triple-layered fluid-solid-solid borehole system that is 30 m away was calculated, and the reflected wave from the interface far from the borehole was clearly shown, which agrees fairly well with the time-distance curve calculated by virtue of the theoretically derived (equations) of source distance-arrival time of reflected wave. Finally, a cross-section chart of the interface (time(depth)) records after adjustment (without the influence of tube wave) was drawn, and the information of interface far away from the borehole (of in-phase axis) was clearly presented.