The Characteristic Of Sediment And Sequence Stratigraphy Of The Queerqueke,in Eastern Tarim Basin

Tarim basin, locates in western China, went through a long geological evolution from Sinian to Neogene. Upper Ordovician Queerqueke in eastern Tarim wide distributes with clastic turbidity sediment, and it is a consensus that it forms by gravity flow sediments. While the sedimentary type, sedimentary formation character, source rock direction and basin setting of the gravity flow system are still un-touched. The isochroneity sequence stratigraphic framework is established by combing knowledge of sedimentary, basin analysis and stratigraphic sedimentary, and the technologies of seismic, well logging, core plug and outcrop observations. The sedimentary type and favorable reservoir of Queerqueke sedimentary system are reveled by analyses the lithology, depositional characterization and sedimentary facies.Research on sequence stratigraphy in Queerqueke was carried out and we divided Queerqueke sedimentary into four sequences, then the sedimentary filling sequence stratigraphic framework was established based on the proposed four sequences. The seismic section, core plug, well logging and outcrop were integrated used to analysis the sedimentary rock type and further investigate the characterization of sedimentary system type, which we divided it into three different type, outer fan fine grain turbidite deposit, middle fan braided channel、middle fan front lobate deposit, respectively.Then the controlling role of source system and see level changes of gravity flow system on deep water gravity flow system evolution was examined. Based on the flute cast direction of Kuruktag outcrop section and palaeocurrent rose diagram, two gravity source system from south and north are identified, which relate to Altyn and Kuruktag, respectively. The four indentified sequence interfaces in Queerqueke sedimentary rock are accordance with the four significant see level changes in middle and late Ordovician.The developing model of deep water gravity system in Eastern Tarim is established and the advantaged reservoirs are further predicted. Turbidite fan front, median grain size sand, is found in Eastern Tarim well1, and relative larger grain size turbidites may be found along the source rock directions. Eastern Tarim well2contains several combination of reservoir and cap rocks. The porosity of core plugs in Eastern Ying well2reaches to24%and the permeability is relative high, which could be ideal reservoir rocks. These turbidite fan sandstones insert into the marine phase source rock, which form advantaged condition for reservoir.