Abstract: There are four kinds of Fault block models in Dongxin shallow layer, ie. parallel, circular-radial, pinnate, and fastigiate fault block. The migration performance of faults is affected byfault level , cycle of fault activity , and fault attitude. The second and third class faults linking shallow layer with source rock controts the migration of oil and gas. The periodic activity of fault controls the periodic vertical migration of petroleum along the fault. There are five kinds of fault attitude, ie. synthetic，antithetic , graben , horst , and”y" type fault attitude. The sealing performance of fault is affected by fault nature, fault displace-
ment, fault attitude, the contact between hanging wall and foot wall, etc. The sealing performance of fault can be judged by fill-ings in fault zone, the sand-mud ratio of the fractured layer, the dip of the fractured surface, pore fluid pressure, the vertical variance of pressure coefficient and geothermal gradient, etc.

Key words: Dongxin shallow layer, fault, migrate, seal, petroleum accumulation