The Controlling Effect of Unconformity Structure on Hydrocarbon Accumulation

Based on lots of previous studies, the unconformity structure characteristics were studied and the controlling effect of unconformity structure on hydrocarbon reservoir, migration path and oil-gas reservoir type were analyzed. The result shows that the unconformity structure is composed of upper basal conglomerate layer, lower weathering clay layer and semi-weathering rock; the interlocking pores in basal conglomerate layer and pore-cave-fracture system in semi-weathering rock are the main storage space of hydrocarbon reservoir; And hydrocarbon migrates laterally through capillary “channeling effect” in interlocking pores, and the pore-cave-fracture system in semi-weathering rock is an important path for hydrocarbon migration laterally and vertically; stratigraphic overlap hydrocarbon reservoir and stratigraphic unconformity reservoir are the two type of reservoirs related to unconformity, and buried hill reservoir is an important type of the latter.