The precise location of CO₂ pipeline leakage based on wavelet noise reduction

Negative pressure wave method is suitable for CO₂ pipeline leakage location detection in CCUS technology, but the noise generated by the surrounding environment and the high pressure in the supercritical CO₂ pipeline affects the positioning accuracy. In this paper, the wavelet transform was applied to decompose and denoise the pressure signal with noise, and the CO₂ pipeline leakage model was established by TGNET simulation software, the feasibility of the leakage model was verified by comparing the shock tube discharge test of Botros. The leakage model was used to denoise the pressure signal with noise using wavelet denoising method, then, the denoised data was processed using the pressure difference conversion and cross-correlation analysis. Finally, the specific time difference of the pressure signal received by each group of pressure sensors was obtained. The leakage model was also applied to the 360000 t/a supercritical CO₂ pipeline transportation scheme in Yanchang Oilfield, and the wavelet noise reduction and cross-correlation analysis of artificially set leakage port pressure noise were carried out. The research shows that the pressure signal after wavelet denoising is more stable and accurate, and the accurate time difference can be obtained, which provides a basis for the subsequent negative pressure wave method to accurately locate the leakage point.