Study On High-resolution Stratigraphy Framework To Yanchang Formation Of Southern Ordos Basin

Ordos basin is stable craton basin, developed large lake, delta deposition in YanChang formation of Triassic system. Based on the theory of high-resolution sequencestratigraphy as the guiding ideology, to do further study about the Extended longitudinalrock group in superimposed style, sequence stratigraphic classification and the causes ofhigh frequency cycle, and the horizontal sequence stratigraphy distribution of the southernOrdos basin.According to the fieldwork of Rui Shui He of southern Ordos basin，Identifying theinternal development of lithologic conversion surface and large sequence interface.Combining previous research data tracking Chang9, at the bottom of the Chang7, Chang4+5large lake flooding surface and Chang2,1fine grained sediment condensationsection. According to the Superposition of lithology combination and large floodingsurface of Rui Shui He profile, Divided into five second-order sequence,18third-ordersequence and hundreds of fourth-order sequence.By using gamma curve to identify the maximum flooding surfaces, large sequencetransformation. According to the characteristics of single well logging curves and thelithology superimposed style, To extend18Wells in southwest Ordos basin group ofsequence stratigraphic classification. And using the drilling location set up between thenorth and the south section sequence stratigraphic framework. The north and the southsection at the top are subjected to different degree of denudation extended set of the Chang1,2section.Because of the complexity of the continental strata, Milankovitch cycles is difficult tobe observed in the continental sedimentation. Continental high frequency cycle the maincontrolling factors of sequence stratigraphy is still controversial. In establishing a groupon the basis of sequence stratigraphic framework, this article through to Wu58well, Dan46Wells, Yan52, Hua300Wells, natural gamma ray spectrum curve analysis, get thecorresponding frequency correlation with meters upper cycle, the error is less than10%,and by time-depth domain transformation estimate the deposition rate. For large typedepression lake basin of Ordos basin Yan Chang formation deposition, the combination ofhigh resolution sequence stratigraphy theory meters upper astronomical orbit cycle controland affect the formation of the high-frequency cycle, deposition and was recorded. makingpeople for Ordos basin sequence stratigraphy research is further extended group.