关键词: 济阳坳陷, 断陷湖盆, 三级层序, 扩展体系域, 断裂坡折带, 低位扇, 砂岩, 隐蔽油气藏群

Abstract: The voilently faulted Eocene-to-Oligocene terrestrial Jiyang Basin has an area of 26000 square kilometers,and its proved geological reserves has reached 60 percent of the total hydrocarbon resource.The basin had entered the conceived deposit exploration stage taking the lithological reservoirs of sandstones as the sort of the chief targets by the time of the mid 1990s.In terms of the sequence stratigraphical principles,the Tertiary Shahejie Formation and Dongying Formation can be divided into six third-band sequences with integral system tract construction and can be further sorted into two categories of deep-faulted and shallow-faulted sequences.The oilshale within the expansion system tract in the deep-faulted third-band sequence is the excellent source rock,because it is rich in organic matter with high hydrocarbon conversion ratio.The sandstone complexes,so-called lower-stand fan,within the lower system tract in deep-faulted third-band sequences mainly include turbidite fan and fan-delta.Due to ideal collocation with the oilshale of the expansion system tract,90 percent of fans are oil-bearing system.These lower-stand fans exist along the faulted slope break,in the appearance of groups and belts,forming conceived lithological sandstone deposits with the prospective reserves over 7000 million barrels.In recent years,based on the theory of "the exploration of the lithological lower-stand fan deposit group along the fault slope break",1640 million barrels of geological crude oil reserves have been proved in the faulted lacustrine of the Jiyang Basin,and 20 million barrels of oil production have been achieved.

Key words: Jiyang Depression, faulted lacustrine basin, third-band sequence, expansion system tract, fault slope break, lower-stand fan, sandstone, conceived deposit group