Abstract: Many stratigraphic reservoirs with unconformity have been found in Wuxia area of the northwestern edge
of Junggar Basin. It is important to study the role of the unconformity in the process of hydrocarbon accumulation.
On the basis of 3D geological model and analysis of Erosion Thickness， the formation of unconformity and burial
history of this area were studied， and the 3D dynamic system was simulated. Simulations show that the three sets of
source rock reach maturity and expulse hydrocarbon at different ages in Wuxia area. The source rocks in Jiamuhe
formation reach maturity at middle Permian and Late Permian Epoch. The source rocks in Fengcheng formation
reachmaturityatLateTraissicEpoch. ThesourcerocksinLowerWu’erheFormationbegintogeneratehydrocarbon
at Jurassic Period. The unconformity conduit simulation shows that the role of unconformity near the source rock
is more important than that far from the source rock in the process of hydrocarbon accumulation， and that oil and
gas migrate along the ridge in the weathering-cracked loess horizon and basal conglomerate. It is the predominant
pathways for oil and gas migration. The lateral migration distance in along the ridge in the weathering-cracked loess
horizon is shorter than that in basal conglomerate. Oil and gas mostly break through thin clay area and migrate to
near horizon in the same unconformity. Unconformity is not only the hydrocarbon passage systems but also the oil
and gas accumulation place. The distribution of Oil and gas pool is relevant to the block of the unconformity. The
Oil and gas pool distribute at the block of unconformity.

Key words: hydrocarbon accumulation simulation, unconformity structure, dynamic system, migration and accu-mulation history, Junggar Basin4