关键词: 多测井曲线, 去噪处理, 小波分析, 正交分析, 曲线重构

Abstract: Using well-log acoustic travel time,natural potential and GR data,the paper reconstructs the travel time of acoustic waves,analyzes the mechanism difference of response of geological body to the three curves,provides correction method for relative depth shift of these curves,and studies the covariance matrix eigenvector filtering approach for de-noising of multiple log curves.On the basis of the above researches,we reconstruct the acoustic travel-time curves based on wavelet multi-scale decomposition.After analyzing the characters of useful signal and noise of wavelet decomposition under various scales with the three curves,we filtered the high frequency part of multi-scale decomposition results of the three curves using correlation filtering technique at adjacent decomposition scales.To ensure the trueness of the reconstructed log curve,we analyzed thoroughly the redundancy(correlativity)and the incorrelativity of the multi-curve multi-scale decomposition results with eigenvalue techniques,and eventually realized the curve reconstruction.Comparison between the reconstructed curve with the drill-hole core log shows an obviously higher resolution of the former in distinguishing sandstone and mudstone.

Key words: multiple log curve, denoising, wavelet analyses, orthogonal analyses, curve reconstruction