Abstract：Generally,the methods of seismic wavelet pick-up can be divided into two categories: determinate wavelet pickup and statistic wavelet pickup.The determinate wavelet pickup does not need any hypothesis about the distribution of reflection coefficient sequence and obtains more accurate wavelet,but is easily affected by various logging errors,especially the velocity errors resulted from inaccurate sonic logging data can lead to distortion of amplitude and phase spectrum in wavelet; the statistic wavelet pickup does not require the logging information and also can obtain wavelet estimation,but needs to make hypothesis about seismic data and distribution of subsurface reflection coefficient sequence,and the resulted precision of wavelet is relative to the satisfied level of hypothetic conditions.The paper made detail commentary abut the methods of determinate wavelet pickup and statistic wavelet pickup,and considered that it can use the idea of subspace decomposition in communication engineering for mixed-phase wavelet pickup,which is based on the orthogonal principle of signal with noise in subspace,creates quadratic form of objective function and does not need to make any hypothesis about the reflection coefficient of strata,therefore,the wavelet pickup is characteristics of high accuracy and good stability.
