Study on Sequence Stratigraphic Division by Using Milankovitch Cycles as Constraints

On the basis of the sequence stratigraphic theory and cyclic stratigraphic theory,the data of GR well logging curve from Well Panxian 3 were processed through db5 wavelet analysis and fast fourier transformation. According to Milankovitch cycles best matching method and the corresponding relations between the ratio of Milankovitch cycles,the wavelet scales of Milankovitch cycles which have been determined by rejecting and selecting the dominant periods in the strata were d3,d5,d6 and d8. Based on the control action for the high frequency sequence and combined the recognition of Milankovitch cycles with the division and correlation of sequence stratigraphy,the stratigraphy division and correlation of the wells were carried out by using Milankovitch cycles as rulers. The results show that the features of Milankovitch curves were made clear,four third-order sequences and two system tracts were classified,the divided sequence stratigraphy basically tallied with the actual geological situation.