China’s largest complex fault-block oil and gas fields-Dongxin oil and gas fields possess sufficient oil and gas sources and well developed reservoir rocks.The inherited uplift helts developed there are favourable for hydrocarbon accumulation.Multi stage faultings resulted in active vertical migration of oil and gas.During bady faulting

hydrocarbons were injected upward along the faults;during stable stage

faults closed gradually

and hydrocarbon that entered shallow strata migrated along the faults to form secondary oil and gas pools

thus forming vertical multi layer hydrocarbon assemblayes.The pools imbricated and formed oil pool

→

oil-gas pool

→

gas pool sequences in ascending order.