Research on microseismic signal denoising based on variational mode decomposition and wavelet energy entropy

Microseismicmonitoringtechnologyiswidelyusedinsuchfieldsasminingengineering,petroleumandgasexploitation,andsafetymonitoring.Inordertosolvetheproblemofrandomnoiseinmicroseismicsignalscollectedbymicroseismicmonitoring,adenoisingalgorithmbasedonvariationalmode decomposition(VMD)combinedwithwaveletenergyentropy(WEE) andimprovedthresholdfunction isproposed.Wavelettransformationisperformedoneachintrinsicmodefunction(IMF)componentafter VMDdecompositionoftheoriginalmicroseismicsignals.Thenoisestateofeachscalesignalischaracterizedbywaveletenergyentropy.Thethresholdofeachscalelayeriscalculatedbywaveletcoefficients ofthemaximumsubintervalofwaveletenergyentropyandthenthemicroseismicsignalsarereconstructedbythenewIMFsdenoisedthroughtheimprovedthresholdfunction.Theresultsfromnumericalsimulationsignalandrealsignalshowthattheproposedalgorithmissuperiortoempiricalmodedecomposi
tion(EMD),ensembleEMD(EEMD)andVMDcombinedwithwaveletenergyentropyhardthreshold functionandsoftthresholdfunction.Thesignal-to-noiseratioofmicroseismicsignalsareimproved.