Sedimentary evolution and favorable hydrocarbon zone prediction in Neogene of Hongsanhanyihao and Niubiziliang region in western Qaidam basin

One super long-term stratigraphic base level circle(the 2nd sequence)Ssql and the corresponding 4 long-term stratigraphic base level circles(the 3rd sequence)Sq1、 Sq2、 Sq3 and Sq4 could be distinguished in Neogene in Hongsan-hanyihao and Niubiziliang area,Qaidam basin by using the ways and principles of the high resolution sequence stratigraphy.Within the correlation framework,two main type depositional systems are identified,namely fan delta and lake depositional systems and it analyzed the composition of the depositional system and facies development in the cycles.The paper points out that Sq1 cycles is the most favorable reservoir rock,and the rock of the fan delta front is the target of the oil exploration.It also points out such area as be-tween the third high point of the Hongsanhanyihao area and the area of unconformity surface structure is the most favorable region for oil and gas exploration now.