Well cementation quality evaluation method based on array acoustic logging

The invention discloses a well cementation quality evaluation method based on array acoustic logging. An array acoustic logging instrument comprises a long-spacing transmitting probe, a short-spacing transmitting probe and array receiving probes, wherein the long-spacing transmitting probe and the short-spacing transmitting probe are arranged along a coaxial line and have different frequencies, and the array receiving probes are arranged at equal intervals; the transmitting probe excites vibration, the array receiving probe receives array logging waveforms with different source distances, casing wave parts in the eight array logging waveforms are taken out and processed, and a time difference frequency-varying curve and an attenuation coefficient frequency-varying curve of casing waves are obtained; and the well cementation quality is evaluated by using the time difference frequency-varying curve and the attenuation coefficient frequency-varying curve. The method is also suitable for old stratums such as lime