Oil and gas fields such as Tahe 3

4

5 and Lunnan buried hill were found in the Ordovician carbonate rocks in Akekule region

Tarim Basin.The oil and gas are mainly distributed in the weathered crust and leaching zones of buried hill

vados and underflow karst with the thickness of 250 m;in paleo karst highland and slopes

the convergent places of fualts and fractures.The carbonate rock reservoirs are fracture

cave and hole types;the Carboniferous mudstone is the cover of the lower Ordovician

the Lower Ordovician dense limestone is impermeable sealing bed

and Late Hercynian is the main pool-forming stage.