1�� College of Earth Sciences��Jilin University��Changchun 130061��China; 2�� Jilin Province Key Laboratory of Oil Shale and Symbiotic Mineral��Changchun 130061��China; 3�� Geological Science Research Institute of Shengli Oilfield��SinoPEC��Dongying 257015��Shandong��China

The sedimentary strata are obvious in cyclicity in the basin��which can be used to distinguish the sequence stratigraphy��responsing to different characters of the logging date�� In order to avoid the subjectivity of division of strata in a visual level��and make the division of sequence stratigraphic units more scientificly��we use the wavelet transform technique to expand 1-D level logging curves to 2-D time-frequency domain��which would show the sedimentary cycles clearly in different times or depth scales�� Based on the logging date of the Meihe Basin��by taking the value rang 0. 25 to 0. 5 amax ��the third to fifth scale sequence sedimentary units have distinctive characteristics in wavelet time-frequency power imaging�� In the wavelet power imaging��the high power site with the characteristics of power reduced upwardly and downwardly��which helps to define the third sequence boundary�� In thethird sequence��from the bottom to the top��the features of power imaging is changed from large scale to small scale then to the stability and finally��to the reversal of large scale��and this four states correspond to the system tracts vertical evolution of LST��TST��HST and RST�� The smaller power imaging could also be recognized as a parasequence�� The model of sequence stratigraphic division based on the wavelet transform technique offers a new method for identifying sequence��