Based on the petroleum-geological data of the Y1 well that is located in the southwestern margin of Maichen Sag of the Beibuwan Basin

in this study

the petroleum-geological and geochemical numerical simulation has been conducted using the PetroMod software.The results show that only the dark mudstones in the second section of Eocene Liushagang Group meet the standard of sufficient organic matter abundance to be defined as hydrocarbon source rock

but they have not reached the hydrocarbon generation threshold because of their low maturity.In addition

the geothermal field of the Maichen depression is generally low

and the mature hydrocarbon generation threshold depth

by comprehensive judgment

has been determined as 2 600 m

which is obviously deeper than that of Eocene hydrocarbon source rocks of the Weixinan and Wushi Sags.As Y1 well is out of drainage range of effective hydrocarbon generation

its structure may not have received sufficient hydrocarbon charge

to become a hydrocarbon accumulation in local structures and trap.Thus

this should result in an empty trap where the Y1 well is targeted.Therefore

favorable zones and traps within the effective hydrocarbon drainage zone of Eocene hydrocarbon source rocks should be focused on

in order to achieve a breakthrough of the commercial hydrocarbon exploration.