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本文研究了井间地震勘探中单界面和低速层导波的速度特征。理论分析说明，单界面可能会存在一种不均匀衰减但不频散的漏能振型波，而不存在Stoneley波。本文推导了低速层导波的频散关系。数值模型计算表明，低速层导波是频散的，其频散关系和相速度大小是与地层速度结构、厚度密切相关的。在相同频率处，可能存在具有不同截频的多阶振型。
This paper studies the velocity characteristics of single-wave and low-velocity waveguides in crosswell seismic exploration. The theoretical analysis shows that there may exist a non-uniform attenuation but non-dispersion leakage energy mode wave in the single interface without Stoneley wave. In this paper, we derive the dispersion relation of low-speed guided waves. The numerical model shows that the guided waves in low velocity are dispersive, and their dispersion relation and phase velocity are closely related to the velocity structure and thickness of the formation. At the same frequency there may be multi-order modes with different cutoff frequencies.