The multilayer source rocks in southern Junggar depression are characterized by their extremely high abundance of hydrocarbon generation.The Permian and Trassic have been buried very deeply in the depression

so they would not have any exploration significance anymore except transporting hydrocarbons upward along faults to shallow reservoirs.Although the Jurassic is a good source of hydrocarbons

conventional accumulations would not be formed in later stage

because it has been deeply buried

as deep as 10000m in the center of the depression

and has become tight and ultra-tight strata.The Jurassic had experienced early formation of deep basin gas and later destruction

modification and adjustment of deep basin gas.Gas accumulations may exist in the following areas. (1) Some deep basin gas reservoirs might have been preserved in Beidapo (Northern Big Slope) area; (2) The 3 rows of structures formed in foothill belt by compressive and shear tectonic movement.Hydrocarbons might have migrated along faults to the shallow structures

resulting in formation of secondary gas reservoirs; (3) Although the Jurassic has very large burial depth

it might become prolific gas reservoir with large reserves again

as a result of the fractures formed in Later stage

thus it would still have large exploration potential; (4) In the deep basin gas area

large attention should be paid to the gas potential in the "sweet points"

such as thick and large sandbodies and ancient traps in the favorable facies zone.