The Character Of Cretaceous Sequence Stratigraphy And Depositionalsystem At East Of The Sandaoqiao Area In The Tarim Basin, Xinjiang

The research region is called East of the Sandaoqiao, which located in the central.of theYakela broken convex in the Tarim Basin. The development of the serial of Yakela, Tiergen,Yaha oil field was proved that this region has a very strong capacity of exploration。Accordingto the need of exploration，more accurate research results of sedimentary facies, depositionalsystem distribution and the evolution and feature of lithofacies paleography are neededurgently.Based on sequence stratigraphy,sedimentology, seismic stratigraphy and lithofacies-paleogeographyfor theoretical guidance, synthetically analysis geologic, logging and seismicdata in the east of the Sandaoqiao area, and establish the isochronal framework of sequencestratigraphy.Analysis the types and the feature of distribution about the depositional systems.Clear the antiquities source direction and sand body macro exhibition cloth law and establishthe depositional model Compiled the lithofacies-paleogeographic map, studypaleogeographic evolution characteristics and evolution.Based on original scheme of the cretaceous stratum division, System analysis thesequence boundary of the Yageliemu Formation, Sushanhe Formation, Baxigai Formation andBashijiqike Formation by using geologic, logging and seismic methods. We divided theCretaceous Formation into two super long-term, six long-term and seventeen medium-termsequences cycle; Through sequence stratigraphic subdivision and correlation of key wells andseismic sections，the sequence stratigraphic framework.This paper divided the sedimentary system of lower Cretaceous at study area into fourtypes mainly including alluvial fan,meandering delta, braided delta,lacustrine facies byanalysing rock components, tectonic setting, logging characteristics, seismic profiles andvertical sedimentary sequences.They can be subdivided into11subfaciers,31microfacies,and the relevant sedimentary models have been set up. Alluvial fan mainlydistributed in Bashijiqike Formation, braided delta mainly distributed in Yageliemu Formation,meandering delta mainly distributed in Baxigai Formation, Sushanhe Formation is consistedof delta front and shallow lacustrine facies.Combined with analysis of provenance, sedimentary facies,sequence division andseismic inversion, adopting super long-term sequence cycle as basic mapping unit.based on single factor analysis and Many factors into figure. this paper have finished the sedimentaryfacies maps of every systems tract within the sequence straigraphic framework of the east ofthe Sandaoqiao area, and described characteristics and evolution of every sequence cycle indetail.