Abstract: Sequence stratigraphy research in Biyang depression indicates, the subtle reservoirs are related to system tracts of sequence stratigraphy, the updip pinchout reservoirs in south steep slope zone are mainly within the lowstand and highstand system tracts(LST and HST), the lithologic lens in the central depression are mainly abnormal geobody of LST and dolomite fracture reservoirs, the reservoirs in the north gentle slope are mainly stratigraphic unconformity, fault unconformity, fault-lithology, fault-nose reservoirs of HST, there also exist delta of LST, stratigraphic overlap of expanding system tracts(EST) and slump lithology of HST. Based on the sequence stratigraphy characteristics and the distribution of various types of reservoirs, the model for reservoir formation within the sequrence stratigraphic framework in the Biyang depression is established. The model indicates that the area around the salt lake zone is the keystone domains of subtle reservoirs exploration such as lithological/stratigraphic reservoirs, which include the geobody of LST, delta of LST, stratigraphic overlap of EST, dolomite fractures of HST, turbidite of HST and fault-lithology of HST.

Key words: Biyang depression, sequence stratigraphy, reservoir types, reservoir formation model, subtle taps