In recent years

a breakthrough has been achieved in the exploration of the Silurian strata in the north slope of the Tazhong Uplift.However

it also reveals the complexity of the hydrocarbon accumulation process

owing to the multistage tectonic movement.In this paper

fluid inclusions analysis is performed on 23 samples of the Silurian strata in the north slope of the Tazhong Uplift

and also faulting activities characteristics were studied.The results indicate that there are four events of oil charging and one event of gas charging.The oil originated from the Cambrian to the Lower Ordovician source rock charged during the Late Hercynian (318-245 Ma)

while oil and gas originated from the Cambrian-Lower Ordovician source rock and Middle-Upper Ordovician source rock charged during the Yanshanian to Middle-Late Himalayan (124-25 Ma).Due to the NE extensional strike-slip faulting

the early stage charged accumulations were destroyed and only residual bitumen remains

even though oil charging was active during the Late Hercynian.The oil and gas recharged during the Middle-Late Himalayan determined the hydrocarbon characteristics in the reservoirs.In all

the major targets for hydrocarbon exploration in the north slope of the Tazhong Uplift shall be accumulations formed during the Yanshanian to Middle-Late Hercynian.