The Ordovician reservoir types of Qianmiqiao buried hill could be divided into 4 types:1.pore cave reservoir;2.fracture reservoir;3.pore cave fracture complex reservoir;4.pore reservoir.The pore cave fracture complex reservoir type is the major reservoir space type and most favourable for hydrocarbon migration and accumulation.The reservoirs are characterized by zonal distribution both vertically and horizentally.In vertical of the 4 zones

the 2nd and 3rd zones are favourable for hydrocarbon accumulation;in horizontal

residual dome is more favourable for reservoir development.The corroded pores and caves formed in Caledomian-earhy Hercynian and their formation was controlled by the characteristics of rock and water

tectonic movement

palaeoclamite and fractures;the formation of the fractures in Indo Chinese and early Yenshan epoches was controlled by tectonic movement

rock characteristics and burial depth.The Indosimian movement early Yenshan movement resulted in large amounts of fractures and recorroded pores in Ordovician reservoirs;the middle late Yenshan movement resulted in serious filling;the Himalayan movement reduced the pore spaces.