Abstract:Substratum correlation is basic work in oil-field development,its precision and accuracy determines if the missed reservoirs can be found or not.For raising the precision of substratum correlation,application of Hilbert-Huang transform in extraction of "three instantaneous" parameters to conduct isochrone substratum classification as well as the correlation methods were introduced in this paper as below:at first using empirical mode decomposition method to process well logging data and obtaining intrinsic mode function with different scales,then according to the requirement for regional isochrone substratum boundary calibration,conducting Hilbert transform to intrinsic mode function with different scales and extracting "three instantaneous" parameters (instantaneous frequency,instantaneous amplitude and instantaneous phase) which reflect the characteristics of isochrone substratum boundary,at last applying high resolution section reconstruction technique in reconstructing instantaneous frequency and obtaining Hilbert spectrum.The cyclic changes for "three instantaneous" parameters and the Hilbert spectrum characteristics can be used to conduct calibration of substratum boundary and correlation of isochrone substratum under the control of the cycle.The method has being utilized in Changqing oil-field,it is proved that the method is effective.