The Establishment of Sequence Stratigraphic Framework and Its Models of Deep Formation in Northern Songliao Basin:Taking the Shahezi Formation of Gulong-Changjiaweizi Fault Depression as an example

The deep exploration of Northern Songliao Basin has got a series of breakthrough,such as Xujiaweizi,and so on.For the recognition of deep geology of Gulong-Changjiaweizi Fault Depression is lower,it is still at the early stage of deep exploration.The Shahezi Formation of the fault depression of Gulong-Changjiaweizi was filled by a suite of fan delta and lacustrine deposits,is the important reservoir bed and source bed.We utilized multipurposely the data of logging,drilling,seismic and so on,applied the theory of sequence stratigraphy to continental fault depression of lake basin deposit,identified the top and bottom surfaces of the third-order sequences of Shahezi Formation,devided it into 2 the third-order sequences,and distinguished from highland systems tract,transgression systems tracts,lowstand systems tracts,established the high precision isochronous sequence stratigraphic framework.Based on the geologic configuration of Shahezi Formation and the tectonic background of the strata development,author established the sequence stratigraphic modes of Shehezi Formation: two-way multistage fault terrace sequence stratigraphic model,double half-graben asymmetric sequence stratigraphic model.