Abstract: The leakage acoustic signal of oil and gas pipeline contains large amount of noise. The common denoising algorithms such as wavelet transform, empirical mode decomposition and variable mode decomposition are studied. According to the characteristics of the leakage acoustic signal, referring to the idea of Wavelet-EMD(Wavelet-Empirical Mode Decomposition) algorithm, combining the improved wavelet threshold denoising and variable mode decomposition, a VMD-Wavelet (Variable Mode Decomposition-Wavelet) algorithm is proposed.Four typical signals with noise are used to verify that VMD-wavelet joint denoising algorithm is superior to other common denoising algorithms in output SNR (Signal Noise Ratio) and minimum mean square error. Finally, the VMD-Wavelet algorithm is applied to the actual pipeline leakage acoustic signal denoising. It is found that the VMD-Wavelet algorithm can achieve a high signal-to-noise ratio and a small mean square error for the pipeline leakage acoustic signal under strong background noise.

Key words: wavelet threshold denoising')">wavelet threshold denoising, empirical mode decomposition, leakage acoustic signal')">variable mode decom-posetion;leakage acoustic signal