Abstract: The migration of oil and gas generated from Jurassic source rocks in Bohu depression of Yanqi basin mainly depends on two modes of layered migration and reticulated migration. The hydrocarbon accumulation process follows the "differential accumulation" principle, and the oil-gas adjustment modes appear in "vertical adjustment" and "horizontal adjustment". Also, the accumulated oil and gas are lost by "exposure condition" and "buried condition". This paper suggests that the key area for further petroleum exploration in Bohu depressions should turn to the lithological reservoirs with "less tectonic movement effects and better oil-gas preservation conditions in the late stage".

Key words: Yanqi basin, Bohu depression, hydrocarbon accumulation mode, Jurassic