Seismic Sedimentology Study Of Akshabulak Formation In 1057 Area,South Turgay Basin

South Turgay Basin is located in south central Kazakhstan.It is a typical Meszoic rift basin,which is composed of graben and horst.1057 area lies in the south of Aryskum Graben,which is in the west of the basin.Guided by the theories of sequence stratigraphy,high-resolution sequence stratigraphy,sedimentary petrology and seismic sedimentology,mainly making use of seismic,log and core data,the study was aimed to establish a sequence framework,make certain the characteristics of sequence stratigraphy,identify the four-rank sequence and analyze the sedimentary features of the Akshabulak Formation.According to the dissection of the known hydrocarbon reservoirs,it figured out the trap styles and the reservoir control factors.And on the basis,lithologic-stratigraphic traps were predicted and evaluated.The Jurassic and early cretaceous strata was divided into 7 third order sequences and 8 sequence boundaries were recognized.The boundaries include 2 primary sequence inerfaces,2 second-order sequence and 4 third order sequence inerfaces.There were 5 interface types,which were consists of basement top surface,river rejuvenation surface,top surface of coal bed,sedimentary transformation and mutation of lithology and log.Akshabulake Formation was subdivided into 3 fourth order sequences.Based on the seismic sedimentology study,1057 area mainly developed delta and lake systems.Distribute channel was clearly depicted,extending in northwest-southeast,swinging from southwest to northeast,widening in a way from bottom to top.Based on the analysis of typical reservoirs in the region,it summed up 3 subtle types of Akshabulake Formation in 1057 area,namely lens trap,sandstone up pinchout trap and statigraphic trap.Distributary channel and mouth bar were taken as favorable facies belt for lithological traps.10 exploration targets were put forward and evaluated to optimize exploration targets.